The Laser-Aided Imager for Cryogenic Applications (LAICA) was developed at the Washington State University (WSU) Hydrogen Properties for Energy Research (HYPER) Center between 2023 and 2025 to investigate flow boiling of liquid cryogens. A detailed description of the system can be found in the conference Proceeding, "Development of a flow boiling visualization experiment for liquid hydrogen."

The data generated between August 2024 and July 2025 was funded through a NASA Space Technology Graduate Research Opportunity (NSTGRO) grant number 80NSSC24K1357 and thus is publicly available here.

Enclosed here are steady state thermodynamic data points (ReportableDataLog_LN2_Final_Cleaned.csv), images (Test08.zip through Test19_Part2.zip), videos (SampleVideos.zip and in TestXX.zip folders), and Python files for analysis (Python.zip), using liquid nitrogen. Raw data points are compiled in "ReportableDataLog_LN2_Final_Cleaned.csv" in chronological order of acquisition. These data points with derived parameters like equilibrium quality, velocity, and nondimensional numbers are compiled in "ReportableDataLog_LN2_Final.csv".

LAICA is a flow boiling cryostat. Due to the complexity of flow boiling phenomena, the specifics of the system are often necessary to properly analyze results. The key specifications are provided below. Further detail is available in associated publications noted at the bottom of this file.

LAICA System Specifications:

• Total length of heated section - 6 in
• Outer diameter of metal pipe - 1.50 in
• Outer diameter of glass pipe - 1.75 in
• Inner diameter of metal and glass pipe - 1.37 in
• Metal pipe material - 316 stainless steel
• Glass pipe material - borosilicate
• Lighting - 532 nm DPSS CW laser with 30 degree fan angle (cylindrical lens), up to 0.75 W
• Camera - 1920x1080 px camera, 899 or 2247 fps, 8-bit grayscale
• Heater - bifilar wound Nichrome wire encased in Stycast 2850-FT

The recommended use of this dataset is as follows:

• Use ReportableDataLog_LN2_Final.csv to access the bulk of the data at steady state and unsteady points of interest
• If a datapoint is of interest to investigate further, identify the test number, in the form "TESTXX"
• To view a time trace (for temperature, pressure, mass flux, or heating), select the .csv datafile from the folder TimeTraces.zip
• To view a video, first identify if it is present in the SampleVideos.zip folder via the list below.
  • If the video is in that folder, download that folder and view the video.
  • If the video is not in that folder, download the folder for the test (for example, Test08.zip) and view images and videos in the "Finals" folder. Images are in .bmp format for lossless data transmission.

File Descriptions

Python.zip

• Heat Transfer LAICA.ipynb is a Jupyter Notebook to plot time traces from LAICA_LN2_Test09_Final.csv – LAICA_LN2_Test19_Final.csv
• FlowRegimeContours.py is a Python file to plot and compare experiment data from ReportableDataLog_LN2_Final.csv with the Ganesan flow regime predictions
• ModelVsExperimentPlotting.py is a Python file to plot data from ReportableDataLog_LN2_Final.csv
• BMPtoAVI.py is a Python file to import images and export movies
• PIV_Processing.py is a Python file to perform PIV and segmentation on images to create time series
• PIV_PostProcessing.py is a Python file to plot and analyze time series of PIV and segmentation from PIV_Processing.py

ReportableDataLog_LN2_Final_Cleaned.csv

Processed thermodynamic and fluid data. "-" is equivalent to an empty space. Data is presented in the columns:

• Data Point - Notates data point
• Heat Flux Applied (kW/m^2) - Heat supplied by the heater divided by heating surface area
• Parasitic Correction (kW/m^2) - Parasitic heat flux determined by boiloff calorimetry, equivalent to heat leak divided by heating surface area
• Total Heat Flux (kW/m^2) - Heat supplied by the heater plus the heat leak determined by boiloff calorimetry
• Steady State? - Whether transient behavior has dampened out
  • "Yes" = no more than ± 0.5 K variation in all temperatures over the 1 minute sample time
  • "No (reason)" = more than ± 0.5 K variation in all temperatures over the 1 minute sample time
• Type (Pre-CHF, Post-CHF, at CHF - vapor layer forms and collapses) - Denotes whether the temperatures indicated pre-critical heat flux, post-critical heat flux or at critical heat flux behavior. Pre-critical heat flux flow is liquid dominated at the wall. Post-critical heat flux flow is vapor dominated at the wall.
  • "Post-CHF" = T5 (K) is greater than Saturation Temp @ P1
  • "at CHF" = T5 (K) oscillated between Saturation Temp @ P1 and a higher temperature
  • "Pre-CHF" = T5 (K) was less than or equal to Saturation Temp @ P1
• Flow Regime - Observed boiling mode from images
  • "Stratified" = at low mass flux, a layered flow where the liquid surface at the bottom of a pipe is calm and vapor is present at the top of the pipe
  • "Stratified-Wavy" = as mass flux increases, the surface of this flow becomes wavy but remains liquid at the bottom and vapor at the top
  • "Plug" = at lower gas velocity, plug flow occurs where liquid sometimes bridges the gap between a stratified liquid layer and the top of the pipe
  • "Slug" = at higher mass fluxes slug flow occurs in which gas bubbles are present in the liquid bridging the gap. Wave crests which bridge the pipe are common in slug flow
  • "Annular" = occurs at sufficiently high mass flux when a constant liquid layer is present at the pipe top wall and bottom wall
• Subcooling at inlet (K) - difference between Saturation Temp @ P1 and T7 (K)
• T1 (K) - temperature along a heated section, flush mounted with wall in flow, 1 in after start of heater, 1.5 in after start of section
• T2 (K) - temperature along a heated section, flush mounted with wall in flow, 2 in after start of heater, 2.5 in after start of section
• T3 (K) - temperature along a heated section, flush mounted with wall in flow, 3 in after start of heater, 3.5 in after start of section
• T4 (K) - temperature along a heated section, flush mounted with wall in flow, 4 in after start of heater, 4.5 in after start of section
• T5 (K) - temperature just after heated section, flush mounted with wall in flow, 5.5 in after start of section
• T6 (K) - temperature just after heated section, mounted on outside wall, 5.5 in after start of section
• T7 (K) - temperature upstream, mounted in thermowell in centerline of flow
• P1(kPa) (upstream) - pressure before T1
• P2 (kPa) (downstream) - pressure after T5 and T6
• Mass Flux (kg/m^2-s) - Mass flow rate divided by flow area
• ± - the greater of the sensor error and the 1 minute sampling time sensor standard deviation

ReportableDataLog_LN2_Final.csv

Processing and more detail for thermodynamic, fluid, and visual data. "-" is equivalent to an empty space. Data is presented in the following columns:

• TEST INFO
  • Data Point - Notates data point
  • Test # - Which test the data point is from
  • Date - When the data point was collected
  • Start Time - Test starting time
  • Time (min) - Start of 1 minute time frame over which the data point was collected. Presented values are the average over this 1 minute.
  • Video Number - If a video was collected which corresponds to this data point, it is noted here in the format "LN2_TestXX_Video#". These videos or video frames can be found in the zipped folder associated with each test.
  • Void Fraction Frames - If void fraction was calculated from the video, the frame numbers which were averaged are noted here. These frames can be found in the zipped folder associated with each test.
• HEATING
  • Heat Flux (W/m^2) (no correction) - Heat supplied by the heater divided by heating surface area
  • Heat Flux (W/m^2, w/ Correction) - Heat supplied by the heater plus the heat leak determined by boiloff calorimetry
  • Heat Flux (kW/m^2) - Corrected heat flux in more common units
  • Heater Power (W) - Heat supplied by the heater
  • Wattage Error (W) - Readability error on heater
  • Parasitic Correction (W) - Heat leak determined by boiloff calorimetry
  • Parasitic Correction (W/m^2) - Parasitic heat flux determined by boiloff calorimetry, equivalent to heat leak divided by heating surface area
  • Total Heating (W) - Heater power plus heat leak
• VACUUM
  • Vacuum Level (Pa) - LAICA vacuum level at time of data point
• STEADY?
  • Steady State? - Whether transient behavior has dampened out
    • "Yes" = no more than ± 0.5 K variation in all temperatures over the 1 minute starting at Time (min).
    • "No (reason)" = more than ± 0.5 K variation in all temperatures over the 1 minute starting at Time (min) with the reason why variation was greater than ± 0.5 K.
  • T1 - temperature along a heated section, flush mounted with wall in flow, 1 in after start of heater, 1.5 in after start of section
  • T2 - temperature along a heated section, flush mounted with wall in flow, 2 in after start of heater, 2.5 in after start of section
  • T3 - temperature along a heated section, flush mounted with wall in flow, 3 in after start of heater, 3.5 in after start of section
  • T4 - temperature along a heated section, flush mounted with wall in flow, 4 in after start of heater, 4.5 in after start of section
  • T5 - temperature just after heated section, flush mounted with wall in flow, 5.5 in after start of section
  • T6 - temperature just after heated section, mounted on outside wall, 5.5 in after start of section
  • T7 - temperature upstream, mounted in thermowell in centerline of flow
  • 1 minute sd - 1 minute standard deviation of value for each sensor. If any are greater than 0.5, the data point is not steady state.
  • Sensor Error T1-T6 (K) - Error for T1-T6
  • Sensor Error T7 (K) - Error for T7
• LABVIEW DATA
  • P1 (psig) - pressure before T1
  • P2 (psig) - pressure after T5 and T6
  • psia - P1 or P2 in psia
  • kPa - P1 or P2 in kPa
  • 1 minute standard deviation (psi) - P1 or P2 1 minute standard deviation in psi
  • 1 minute standard deviation (kPa) - P1 or P2 1 minute standard deviation in kPa
  • Sensor Error (kPa) - P1 and P2 error
  • Saturation Temp @ P1 (K) - Fluid saturation temperature calculated from P1 using REFPROP (E. W. Lemmon, I. H. Bell, M. L. Huber, and M. O. McLinden, REFPROP Reference Fluid Thermodynamic and Transport Properties. (2018). National Institutes for Standards and Technology.)
  • Mass Flow Rate (g/s) - Mass flow rate determined downstream at an Alicat orifice type mass flow meter
  • 1 minute variation (g/s) - 1 minute standard deviation of mass flow
  • Sensor Error (g/s) - Mass flow meter error
  • Mass Flux (kg/m^2-s) - Mass flow rate divided by flow area
  • 1 minute variation (kg/m^2-s) - 1 minute standard deviation of mass flux
  • Sensor Error (kg/m^2-s) - Mass flow meter error in mass flux units
  • Mass Flux Error (kg/m^2-s) - The greater of the values for Sensor Error (kg/m^2-s) and 1 minute variation (kg/m^2-s)
• HTC
  • Corrected Heat Transfer Coefficient (W/m^2) - Heat transfer coefficient, defined as Heat Flux (W/m^2, w/ Correction) multiplied by (T7 minus T5)
  • del h / del Q = 1/(AdT) - Propagation of heater error for heat transfer coefficient
  • del h / del T5 = -Q/(AdT^2) - Propagation of T5 error for heat transfer coefficient
  • del h / del T7 = -Q/(AdT^2) - Propagation of T7 error for heat transfer coefficient
  • bias error - Total bias error for heat transfer coefficient
  • uncertainty error - Total uncertainty error based on standard deviations for heat transfer coefficient
  • total error - Total measurement error for heat transfer coefficient
  • Error Percent - Measurement error as a fraction of the measurement
  • Model HTC [W * m^-2 * K^-1] - Heat transfer coefficient predicted for this heat flux and mass flux in this tube, predicted by the Ganesan cryogenic flow boiling correlations (V. Ganesan, “Development of universal databases and predictive tools for two-phase heat transfer and pressure drop in cryogenic flow boiling heated tube experiments,” Purdue University, 2023.)
  • HTC % Deviation - Predicted minus actual, divided by actual
  • HTC Model % Error - Predicted minus actual, divided by predicted
• BOILING MODE
  • Actual Type (Pre-CHF, Post-CHF, at CHF - vapor layer forms and collapses) - Denotes whether the temperatures indicated pre-critical heat flux, post-critical heat flux or at critical heat flux behavior. Pre-critical heat flux flow is liquid dominated at the wall. Post-critical heat flux flow is vapor dominated at the wall.
    • "Post-CHF" = T5 is greater than Saturation Temp @ P1 (K)
    • "at CHF" = T5 oscillated between Saturation Temp @ P1 (K) and a higher temperature
    • "Pre-CHF" = T5 was less than or equal to Saturation Temp @ P1 (K)
  • Actual Boiling Mode - Observed boiling mode from images
    • "Stratified" = at low mass flux, a layered flow where the liquid surface at the bottom of a pipe is calm and vapor is present at the top of the pipe
    • "Stratified-Wavy" = as mass flux increases, the surface of this flow becomes wavy but remains liquid at the bottom and vapor at the top
    • "Plug" = at lower gas velocity, plug flow occurs where liquid sometimes bridges the gap between a stratified liquid layer and the top of the pipe
    • "Slug" = at higher mass fluxes slug flow occurs in which gas bubbles are present in the liquid bridging the gap. Wave crests which bridge the pipe are common in slug flow
    • "Annular" = occurs at sufficiently high mass flux when a constant liquid layer is present at the pipe top wall and bottom wall
  • Model Type (Pre-CHF, Post-CHF) - Prediction from Ganesan model of pre-CHF or post-CHF boiling (V. Ganesan, “Development of universal databases and predictive tools for two-phase heat transfer and pressure drop in cryogenic flow boiling heated tube experiments,” Purdue University, 2023.)
  • Model Boiling Mode - Prediction from Ganesan model of boiling mode
    • "Nucleate Boiling" = heat addition to single phase liquid at saturated conditions causes bubbles to form and the fluid enters pre-CHF nucleate boiling (NB)
    • "Annular" = occurs at sufficiently high mass flux when a constant liquid layer is present at the pipe top wall and bottom wall
    • "IAFB" = a post-CHF boiling mode for high velocity flows and high heat flux. At CHF, local wall bubbles coalesce into a vapor layer at the pipe edge, suspending a liquid core in the pipe. This is known as inverted annular film boiling (IAFB) or inverted annular flow.
    • "DFFB" = a post-CHF boiling mode. With heat addition, the fluid gradually transitions from fully liquid to fully gas, sometimes developing into annular flow with liquid at the walls and a gas core. Further heating causes liquid filaments to break away from the bulk flow and then disintegrate into droplets. This is known as dispersed flow film boiling (DFFB).
• FORCING GANESAN TO ID PRE-CHF
  • Regime - Nucleate boiling or annular flow as IAFB and DFFB are prohibited
  • HTC [W * m^-2 * K^-1] - Heat transfer coefficient predicted for this heat flux and mass flux in this tube, predicted by the Ganesan cryogenic flow boiling correlations with only pre-CHF evaluated (V. Ganesan, “Development of universal databases and predictive tools for two-phase heat transfer and pressure drop in cryogenic flow boiling heated tube experiments,” Purdue University, 2023.)
  • HTC % Error - Predicted minus actual, divided by actual
  • HTC Model % Error - Predicted minus actual, divided by predicted
• HTC (Wojtan)
  • Vapor HTC [W m^-2 * K^-1] - Heat transfer coefficient predicted by Wojtan model (L. Wojtan, T. Ursenbacher, and J. R. Thome, “Investigation of flow boiling in horizontal tubes: Part II—Development of a new heat transfer model for stratified-wavy, dryout and mist flow regimes,” Int. J. Heat Mass Transf., vol. 48, no. 14, pp. 2970–2985, Jul. 2005, doi: 10.1016/j.ijheatmasstransfer.2004.12.013.)
• Integrated
  • Wojtan with Pre-CHF Ganesan using Wojtan patching, HTC [W m^-2 * K^-1] - Patching the Wojtan heat transfer coefficient for vapor with the Ganesan heat transfer coefficient for liquid (pre-CHF) based on void fraction using the integration method described in Wojtan
• Average
  • Average HTC between Wojtan and Pre-CHF Ganesan - Patching the Wojtan heat transfer coefficient for vapor with the Ganesan heat transfer coefficient for liquid (pre-CHF) by averaging
• HTC (Hendricks)
  • T_inside (from T6) - Inner wall temperature calculated from outer wall temperature using the method described by Hendricks (R. C. Hendricks, R. W. Graham, Y. Y. Hsu, and R. Friedman, “Experimental heat transfer and pressure drop of liquid hydrogen flowing through a heated tube.” NASA, May 1961. [Online]. Available: https://apps.dtic.mil/sti/tr/pdf/AD0255524.pdf)
  • HTC (T_inside vs T7) - Heat transfer coefficient, defined as Heat Flux (W/m^2, w/ Correction) multiplied by (T_inside (from T6) minus T5)
• HTC (Hendricks) vs Ganesan Full
  • HTC (Hendricks) vs Ganesan Full % Deviation - Ganesan minus Hendricks, divided by Hendricks
  • HTC (Hendricks) vs Ganesan Full Model % Error - Ganesan minus Hendricks, divided by Ganesan
• HTC (Hendricks) vs Pre-CHF Ganesan
  • HTC (Hendricks) vs Pre-CHF Ganesan % Deviation - Ganesan minus Hendricks, divided by Hendricks
  • HTC (Hendricks) vs Pre-CHF Ganesan Model % Error - Ganesan minus Hendricks, divided by Ganesan
• HTC (Hendricks) vs Wojtan
  • HTC (Hendricks) vs Wojtan % Deviation - Wojtan minus Hendricks, divided by Hendricks
  • HTC (Hendricks) vs Wojtan Model % Error - Wojtan minus Hendricks, divided by Wojtan
• HTC (average Hendricks with T5) vs Pre-CHF Ganesan
  • T_avg - Average T5 and T_inside (from T6) to get average inner wall temperature
  • HTC (T_avg vs T7) - Heat transfer coefficient, defined as Heat Flux (W/m^2, w/ Correction) multiplied by (T_avg minus T5)
  • HTC (average Hendricks with T5) vs Pre-CHF Ganesan % Deviation - Ganesan minus Average, divided by Average
  • HTC (average Hendricks with T5) vs Pre-CHF Ganesan Model % Error - Ganesan minus Average, divided by Ganesan
• HTC (average Hendricks with T5) vs Integrated
  • HTC (average Hendricks with T5) vs Integrated % Deviation - Integrated minus Average, divided by Average
  • HTC (average Hendricks with T5) vs Integrated Model % Error - Integrated minus Average, divided by Integrated
• HTC (Hendricks) vs Integrated
  • HTC (Hendricks) vs Integrated % Deviation - Integrated minus Hendricks, divided by Hendricks
  • HTC (Hendricks) vs Integrated Model % Error - Integrated minus Hendricks, divided by Integrated
• HTC (average Hendricks with T5) vs Average (Pre-CHF with Wojtan)
  • HTC (average Hendricks with T5) vs Average (Pre-CHF with Wojtan) % Deviation - Average HTC between Wojtan and Pre-CHF Ganesan minus HTC (T_avg vs T7), divided by HTC (T_avg vs T7)
  • HTC (average Hendricks with T5) vs Average (Pre-CHF with Wojtan) Model % Error - Average HTC between Wojtan and Pre-CHF Ganesan minus HTC (T_avg vs T7), divided by Average HTC between Wojtan and Pre-CHF Ganesan
• HTC (Hendricks) vs Average (Pre-CHF Ganesan with Wojtan)
  • HTC (Hendricks) vs Average (Pre-CHF Ganesan with Wojtan) % Deviation - Average HTC between Wojtan and Pre-CHF Ganesan minus Hendricks, divided by Hendricks
  • HTC (Hendricks) vs Average (Pre-CHF Ganesan with Wojtan) Model % Error - Average HTC between Wojtan and Pre-CHF Ganesan minus Hendricks, divided by Average HTC between Wojtan and Pre-CHF Ganesan
  • Reduction in Absolute Percent Error from Using Average Wojtan and Pre-CHF Ganesan - Reduction in % deviation from Pre-CHF Ganesan vs Hendricks to Pre-CHF Ganesan averaged with Wojtan vs Hendricks
• HTC Multiplier - Hendricks divided by Pre-CHF Ganesan
• LAICA SPECS - Surface area, inner diameter, flow cross-sectional area, gravitry, outer diameter, length of heater, shape factor defined by Hendricks, thermal conductivity of the pipe
• INLET PROPS (P1)
  • Inlet Quality - Model - set to zero based on optimum condition of saturated inlet conditions
  • Inlet Quality - Equil - equilibrium mass fraction based on temperatures, heat input, and mass flow rate
  • Inlet Enthalpy (kJ/kg) - Enthalpy of fluid in
  • Subcooling at inlet (K) - difference between Saturation Temp @ P1 (K) and T7
  • Inlet Heat of Vaporization (sat. P1, kJ/kg) - heat to vaporize fluid based on P1
  • Inlet Sat. Liquid Enthalpy (P1) - enthalpy of saturated liquid at inlet, based on REFPROP
  • Inlet Sat. Vapor Enthalpy (P1) - enthalpy of saturated vapor at inlet, based on REFPROP
  • L Thermal Conductivity (mW/m-K) - thermal conductivity of liquid at inlet, based on REFPROP
  • G Thermal Conductivity (mW/m-K) - thermal conductivity of vapor at inlet, based on REFPROP
  • L Viscosity (uPa-s) - viscosity of saturated liquid at inlet, based on REFPROP
  • G Viscosity (uPa-s) - viscosity of saturated vapor at inlet, based on REFPROP
  • L Density (kg/m^3) - density of saturated liquid at inlet, based on REFPROP
  • G Density (kg/m^3) - density of saturated vapor at inlet, based on REFPROP
  • Surface Tension (sat. P1, mN/m) - surface tension of saturated liquid at inlet, based on REFPROP
• OUTLET PROPS (P2)
  • Outlet Sat. Liquid Enthalpy (P2)
  • Outlet Sat. Vapor Enthalpy (P2)
  • Outlet liquid dynamic viscosity (sat. P, uPa-s)
  • Outlet vapor dynamic viscosity (sat. P, uPa-s)
  • Outlet liquid density (kg/m^3)
  • Outlet vapor density (kg/m^3)
  • Surface tension (mN/m)
• dP
  • actual - P1 minus P2
  • model (full) - Pressure drop predicted by Ganesan model
  • % error - model minus actual, divided by actual
  • model % error - model minus actual, divided by model
• QUALITY AND VOID FRACTION
  • Interface Height (m) - Height of liquid-vapor interface determined from images based on method described in Thesis (I. Wells, "Heat Flux in Low Mass Flux Horizontal Cryogenic Flow", Masters Thesis (2025).)
  • Chord Angle - Used in calculation of void fraction, given in Bowers and Hrnjak (C. Bowers and P. Hrnjak, “Determination of Void Fraction in Separated Two-Phase Flows Using Optical Techniques,” Int. Refrig. Air Cond. Conf., Jul. 2010, [Online]. Available: https://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=2082&context=iracc)
  • Area L (m^2) - Liquid area
  • Area V (m^2) - Vapor area
  • Outlet Void Fraction - Segmentation - Void fraction determined from Interface Height (m)
  • Outlet Quality - Segmentation - Quality from void fraction using Zivi's correlation (S. M. Zivi, “Estimation of Steady-State Steam Void-Fraction by Means of the Principle of Minimum Entropy Production,” J. Heat Transf., vol. 86, no. 2, pp. 247–251, May 1964, doi: 10.1115/1.3687113.)
  • Two-Phase Enthalpy (kJ/kg) - Enthalpy from Inlet Enthalpy (kJ/kg) plus (Total Heating (W) divided by Mass Flow Rate (g/s))
  • Outlet Quality - Equil - Quality based on *Two-Phase Enthalpy(kJ/kg)
  • Outlet Void Fraction - Equil - Void fraction based on Outlet Quality - Equil using Zivi's correlation
  • Outlet Quality - Model - Predicted outlet quality from Ganesan model
  • Void Fraction - Model - Predicted outlet void fraction from Ganesan model
  • Percent Error vs Equil - Equil minus Ganesan, divided by Equil
  • Model Percent Error vs Equil - Equil minus Ganesan, divided by Ganesan
• VELOCITY
  • Liquid superficial velocity (mm/s) - Model - volumetric flow rate of liquid per unit of cross-sectional area of the full channel, predicted using Ganesan model
  • Vapor superficial velocity (mm/s) - Model - volumetric flow rate of vapor per unit of cross-sectional area of the full channel, predicted using Ganesan model
  • Liquid phase velocity (mm/s) - Model - the superficial velocity of liquid divided by the fraction of the pipe volume occupied by the liquid, predicted using Ganesan model
  • Vapor phase velocity (mm/s) - Model - the superficial velocity of vapor divided by the fraction of the pipe volume occupied by the vapor, predicted using Ganesan model
  • Liquid superficial velocity (mm/s) - Equil - volumetric flow rate of liquid per unit of cross-sectional area of the full channel, based on equilibrium quality
  • Vapor superficial velocity (mm/s) - Equil - volumetric flow rate of vapor per unit of cross-sectional area of the full channel, based on equilibrium quality
  • Liquid phase velocity (mm/s) - Equil - the superficial velocity of liquid divided by the fraction of the pipe volume occupied by the liquid, based on equilibrium quality
  • Vapor phase velocity (mm/s) - Equil - the superficial velocity of vapor divided by the fraction of the pipe volume occupied by the vapor, based on equilibrium quality
  • Liquid superficial velocity (mm/s) - Segmentation - volumetric flow rate of liquid per unit of cross-sectional area of the full channel, based on images
  • Vapor superficial velocity (mm/s) - Segmentation - volumetric flow rate of vapor per unit of cross-sectional area of the full channel, based on images
  • Liquid phase velocity (mm/s) - Segmentation - the superficial velocity of liquid divided by the fraction of the pipe volume occupied by the liquid, based on images
  • Vapor phase velocity (mm/s) - Segmentation - the superficial velocity of vapor divided by the fraction of the pipe volume occupied by the vapor, based on images
  • Average velocity (mm/s) - PIV - average velocity in tube determined by a particle image velocimetry (PIV) algorithm based on OpenPIV (A. Liberzon et al., OpenPIV/openpiv-python: OpenPIV - Python (v0.22.2) with a new extended search PIV grid option. (Jul. 04, 2020). Python. [Online]. Available: http://www.openpiv.net/index.html)
  • Mixture velocity (mm/s) - Model - Velocity defined as mass flow rate divided by liquid density, times (1 plus (outletQuality times (liquid-vapor ratio minus 1))), with quality defined by the Ganesan model
  • Mixture velocity (mm/s) - Equil - Velocity defined as mass flow rate divided by liquid density, times (1 plus (outletQuality times (liquid-vapor ratio minus 1))), with quality defined by the equlibrium value
  • Mixture velocity (mm/s) - Segmentation - Velocity defined as mass flow rate divided by liquid density, times (1 plus (outletQuality times (liquid-vapor ratio minus 1))), with quality defined by images
  • All liquid velocity (mm/s) - Velocity based on mass flow rate and density of liquid
  • All vapor velocity (mm/s) - Velocity based on mass flow rate and density of vapor
  • % Error - Vapor Superficial Velocity - Model vs Segmentation
  • % Error - Vapor Superficial Velocity - Segmentation vs Model
  • Error - Vapor Superficial Velocity - Model vs PIV
  • Error - Vapor Superficial Velocity - PIV vs Model
• DIMENSIONLESS NUMBERS
  • Reynolds numbers, based on velocities
  • Boiling numbers defined in Ganesan, based on qualities
  • Bond numbers defined in Ganesan, based on qualities
  • Inlet liquid Capillary number defined in Ganesan
  • Inlet Confinement number defined in Ganesan
  • Inlet Galileo number defined in Ganesan
  • Inlet Liquid-Only Weber Number defined in Ganesan
  • Nusselt numbers defined in Ganesan, based on heat transfer coefficient
  • Froude number defined in Ganesan, based on qualities
  • Density ratio, liquid divided by vapor
  • Prandtl number, defined in Ganesan
  • Atwood number, defined in Ganesan
  • Largest Lyapunov Exponent (PIV) based on nolds algorithm applied to particle image velocimetry average velocities (https://cschoel.github.io/nolds/)
  • q''/G - Heat flux divided by mass flux
  • mass flow rate from PIV - PIV velocity times density at P1 times pipe flow area
  • Model Error vs mass flow rate - PIV mass flow rate minus actual mass flow rate, divided by actual mass flow rate
  • Error vs mass flow rate - PIV mass flow rate minus actual mass flow rate, divided by PIV mass flow rate
  • mass flow rate from segmentation - liquid phase velocity (g/s) - (Outlet Quality - Segmentation) times outlet vapor density plus outlet liquid density times (1-quality) times (Liquid phase velocity - Segmentation) times pipe flow area
  • Mass flow rate from PIV times void fraction - PIV mass flow rate times void fraction. The following two columns are the error and model error using the total mass flow rate from sensors as the true value. Some of the values in these columns are shown as "#VALUE!", in which case they should be considered an empty space.

TimeTraces.zip

Raw data time traces for thermodynamic and fluids sensors for Test 09 through Test 19. This includes mass flow, pressure, temperature, and heating. No time trace for Test 08 exists. Test 09 had temperature sensors mounted at the top and bottom of the pipe instead of at the centerline. Due to software errors, temperature sensor 7 was unable to directly output temperature. Instead, it output the sensor voltage, which was converted to temperature using the table to the right of the main data in each file. Both the original sensor voltage and the temperature are presented. In each file, the column format is:

• Time - Time in ms for temperature sensors
• Time (min) - Time in mins for temperature sensors
• Input 1 - T1 in K
• Input 2 - T2 in K
• Input 3 - T3 in K
• Input 4 - T4 in K
• Input 5 - T5 in K
• Input 6 - T6 in K
• Input 7 - T7 sensor output
• Input 7 Temp - T7 in K
• Notes
• Time(s) - Time in s for pressure sensors, mass flow meters, and external heating
• Time(min) - Time in mins for pressure sensors, mass flow meters, and external heating
• Upstream PT (PSIG) - P1 in psig
• Downstream PT (PSIG) - P2 in psig
• Mass Flow Rate (g/s) - Mass flow meter 1 in g/s
• Mass Flow Rate (g/s) 2 - Mass flow meter 2 in g/s
• Mass Flow (g/s) - Summed mass flow meters in g/s
• External Heating (W) - Heating applied in W

SampleVideos.zip

Some videos are collected here for a smaller download size. They are listed below. They are either .mp4 or .avi format. Due to the large file sizes, VLC media player is recommended for video playback (https://www.videolan.org/vlc/).

• LN2_Test08_4
• LN2_Test09_16
• LN2_Test10_2
• LN2_Test11_2
• LN2_Test13_11
• LN2_Test14_1
• LN2_Test14_4
• LN2_Test14_8
• LN2_Test15_15
• LN2_Test16_5
• LN2_Test17_3
• LN2_Test17_4
• LN2_Test18_2
• LN2_Test19_1
• LN2_Test19_19

Test08.zip through Test19_Part2.zip

A list of the videos of interest to the authors is provided here. Some are provided in the SampleVideos.zip folder:

Further detail on tests and zipped folders:

• Test 08-11 were commissioning tests to investigate chilldown with high heat leak due to improper vacuum. A camera viewed the flow from above. No time trace for Test 08 exists. Test 09 had temperature sensors mounted at the top and bottom of the pipe instead of at the centerline.
  • Test08.zip
    • Originals - Contains the .xml file with the timestamps for the videos
    • Finals - Videos for Test08_3, Test08_4, Test08_5, image capture properties, and images in zipped folders LN2_Test08_1.zip through LN2_Test08_15.zip. These zipped folders may need to be extracted with 7zip due to LZMA compression algorithm being used. Details are below. Images do not have time stamps.
  • Test09.zip
    • Originals - Contains the .csv files for temperature and time traces output by the computer as well as the .xml file with the timestamps for the videos and the .seq file for video playback in StreamPix10, if desired.
    • Finals - Videos for Test09_3, Test09_10, Test09_13, Test09_16, Test09_17, Test09_20, image capture properties, final time traces for thermal and fluid properties, and images in folders LN2_Test09_1 through LN2_Test09_26. Images have time stamps for correlation with time traces.
  • Test10.zip
    • Originals - Contains the .csv files for temperature and time traces output by the computer as well as the .xml file with the timestamps for the videos and the .seq file for video playback in StreamPix10, if desired.
    • Finals - Videos for Test10_1, Test10_2, Test10_3, and Test10_7, image capture properties, final time traces for thermal and fluid properties, and images in folders LN2_Test10_1 through LN2_Test10_7. Images have time stamps for correlation with time traces.
  • Test11.zip
    • Originals - Contains the .csv files for temperature and time traces output by the computer
    • Finals - Videos for Test11_2, Test11_3, Test11_8, Test11_15, and Test11_17, image capture properties, final time traces for thermal and fluid properties, and images in one folder Images. Images do not have time stamps.
• Test 12-13 were the first steady state tests, and had high heat leak due to improper vacuum. This has been compensated for in heat transfer coefficient calculations. A camera viewed the flow from above.
  • Test12.zip
    • Originals - Contains the .csv files for temperature and vacuum pressure output by the computer as well as the .xml file with the timestamps for the videos and the .seq file for video playback in StreamPix10, if desired.
    • Working - Contains the .csv files and an .mp4 file processing the originals
    • Finals - Videos for Test12_1, Test12_2, Test12_3n4, Test12_5n6, and Test12_7, Test12_8, Test12_9, Test12_10, Test12_11, Test12_12, image capture properties, final time traces for thermal properties and vacuum pressure, and images in one folder Images. Images have time stamps for correlation with time traces.
  • Test13.zip
    • Originals - Contains the .csv files for temperature and time traces output by the computer as well as the .xml file with the timestamps for the videos and the .seq file for video playback in StreamPix10, if desired.
    • Finals - Videos for Test13_4, Test13_6, Test13_7, Test13_8, Test13_11, Test13_13, image capture properties, final time traces for thermal and fluid properties, and images in folders LN2_Test13_1 through LN2_Test13_7. Images do not have time stamps.
• Test 14 chilled down with low heat leak due to a proper vacuum. A camera viewed the flow from the side, confirming stratified flow. The test was aborted after chilldown due to venting of liquid nitrogen followed by improper reseating of pressure relief device.
  • Test14.zip
    • Originals - Contains the .csv files for temperature and time traces output by the computer and the .seq file for video playback in StreamPix10, if desired.
    • Finals - Videos for Test14_1, Test14_3, Test14_4, Test14_7, Test14_8, Test14_11, image capture properties, final time traces for thermal and fluid properties, and all images in one folder Images with additional folders for LN2_Test14_3, LN2_Test14_4, and LN2_Test14_11. Images do not have time stamps.
• Test 15 chilled down with low heat leak. A camera viewed the flow from the side. Mass flow rates between 1.5 and 2.5 g/s were investigated at steady state.
  • Test15.zip
    • Originals - Contains the .csv files for temperature and time traces output by the computer as well as the .xml file with the timestamps for the videos and the .seq file for video playback in StreamPix10, if desired.
    • Finals - Videos for Test15_1, Test15_3, Test15_4, Test15_7, Test15_8, Test15_9, Test15_12, Test15_15, Test15_17, image capture properties, final time traces for thermal and fluid properties, and images in folders LN2_Test15_1 through LN2_Test15_19. Images have time stamps for correlation with time traces.
• Test 16 chilled down overnight, running out of liquid before steady state points could be investigated. A camera viewed the flow from the side.
  • Test16.zip
    • Originals - Contains the .csv files for temperature and time traces output by the computer as well as the .xml file with the timestamps for the videos and the .seq file for video playback in StreamPix10, if desired.
    • Finals - Videos for Test16_1 through Test16_8, image capture properties, final time traces for thermal and fluid properties, and images in folders LN2_Test16_1 through LN2_Test16_10. Images have time stamps for correlation with time traces.
• Test 17 chilled down overnight. Steady state points were investigated at lower pressure due to long chilldown. A camera viewed the flow from the side. Test 15 points were repeated, followed by an attempted Post-CHF steady state point at a flow rate of 4 g/s, resulting in heater burnout. A camera viewed the flow from the side.
  • Test17.zip
    • Originals - Contains the .csv files for temperature and time traces output by the computer as well as the .xml file with the timestamps for the videos and the .seq file for video playback in StreamPix10, if desired.
    • Finals - Videos for Test17_3 through Test17_25, image capture properties, final time traces for thermal and fluid properties, and images in folders LN2_Test17_1 through LN2_Test17_25. Images have time stamps for correlation with time traces.
• Test 18 chilled down over 4 hours. Test points were investigated at 0.2 g/s and 4.8 g/s again. The heater burnt out again. A camera viewed the flow from the side, but due to improper alignment of blackout fabric the bottom half of the pipe is obscured. For this reason, most Test 18 videos are omitted.
  • Test18.zip
    • Originals - Contains the .csv files for temperature and time traces output by the computer as well as the .xml file with the timestamps for the videos.
    • Finals - Videos for Test18_2 and Test18_3, image capture properties, final time traces for thermal and fluid properties, and images in one folder Images. Images have time stamps for correlation with time traces.
• Test 19 chilled down over 4 hours. Test points were investigated at low heater power with varied mass flow rate from 1.8 g/s to 8.8 g/s. At the highest mass flux, the heater burnt out again. A camera viewed the flow from the side and identified each intermittent and stratified flow regime. Test 19 has the most data, and therefore extensively uses compression to manage file size. Details on this compression are below. It is recommended to use 7zip to unzip all Test19 folders and subfolders.
  • Test19_Part1.zip
    • Originals - Contains the .csv files for temperature and time traces output by the computer as well as the .xml file with the timestamps for the videos.
    • Finals - Videos for Test19_1 and Test19_19, image capture properties, final time traces for thermal and fluid properties, and images in folders LN2_Test19_1 through LN2_Test19_16. Images have time stamps for correlation with time traces.
  • Test19_Part2.zip
    • Finals - Images in folders LN2_Test19_17 through LN2_Test19_21, LN2_Test19_23 through LN2_Test19_32, LN2_Test19_36, LN2_Test19_42, and LN2_Test19_44 through LN2_Test19_46. Images have time stamps for correlation with time traces. Some images are omitted here due to file size limits.

Compression details:

• Format: .zip
• Compression level: 9 - Ultra
• Compression method: LZMA (https://en.wikipedia.org/wiki/LZMA)
• Dictionary size: 1536 MB
• Word size: 273

It is recommended to use 7-zip (https://7-zip.org/) to uncompress these files, as the LZMA format is native to 7-zip and the program was used for compression.

Software

Video Playback: VLC Media Player is recommended (https://www.videolan.org/vlc/)
Test08.zip through Test19_Part2.zip decompression: 7-zip is recommended (https://7-zip.org/)
Image re-export: StreamPix10 can be used to open .seq files (https://www.norpix.com/products/streampix/streampix.php)

Author Info

Author: Ian Wells

Point of Contact: Professor Jacob Leachman, jacob.leachman@wsu.edu

Related Work

• I. Wells, "Heat Flux in Low Mass Flux Horizontal Cryogenic Flow", Masters Thesis (2025).
• I. Wells, Y. Gitter, J. Hartwig, J. Leachman, “Liquid nitrogen horizontal flow boiling measurements and visualization at low mass flux.” Cryogenics, (In Preparation).
• I. Wells, S. Abi-Saad, T. Sibilli, J. Hartwig, J. Leachman, “Development of a flow boiling visualization experiment for liquid hydrogen.” Advances in Cryogenic Engineering: Proceedings of the Cryogenic Engineering Conference (CEC) 2025, (In Review).