DOI: 10.5061/dryad.6djh9w1ff
title: Dataset to accompany: Heat flux in low mass flux horizontal cryogenic flow

description: Current two-phase cryogenic heat transfer models are used to predict flow
 behavior of cryogenic fluids during transfer, as a heat sink, and when
 used in specialized heat exchange applications. To address errors in
 current predictions for horizontal flow at low mass flux with large tubes,
 this dataset presents thermodynamic data and high-speed imaging for liquid
 nitrogen flow in a tube of inner diameter of 34.8 mm at mass fluxes
 smaller than 10 kg/(m^2 ^s). A description of the test apparatus, further
 details on test conditions, and comparison with existing models are given
 in the thesis, "Heat flux in low mass flux horizontal cryogenic
 flow". Included in this dataset are a table of steady and unsteady
 datapoints, time traces from each test, the most relevant images from each
 test, and Python files to plot data.
description: # LAICA Data Repository - August 2024 - July 2025 --- 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/(A*dT) -
 Propagation of heater error for heat transfer coefficient * *del h / del
 T5 = -Q/(A*dT^2) - Propagation of *T5* error for heat transfer coefficient
 * *del h / del T7 = -Q/(A*dT^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](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](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](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/](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/](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: | **Test** | **Video Number** | **Camera Position** | **Note** | | :------- | :--------------- | :------------------ | :---------------------------------------------------------- | | 9 | 3 | Above | Droplets from above | | 9 | 13 | Above | Caustics from above | | 10 | 2 | Above | Droplet flow | | 10 | 3 | Above | Droplet annihilation | | 15 | 7 | Side | Data Point 16 | | 15 | 9 | Side | Data Point 21 | | 15 | 12 | Side | Data Point 22 | | 15 | 16 | Side | Data Point 29 | | 17 | 3 | Side | Data Point 32 | | 17 | 4 | Side | Data Point 33 | | 17 | 5 | Side | Slug and Plug | | 17 | 9 | Side | Slug and Plug, higher flow rate so bubbles follow flow more | | 17 | 24 | Side | Post-CHF at high flow rate | | 19 | 1 | Side | IAFB-&gt;NB | | 19 | 16 | Side | | | 19 | 44 | Side | Data Point 44 | | 19 | 45 | Side | Data Point 46 | 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](https://en.wikipedia.org/wiki/LZMA)) * Dictionary size: 1536 MB * Word size: 273 It is recommended to use 7-zip ([https://7-zip.org/](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/](https://www.videolan.org/vlc/)) **Test08.zip** through **Test19_Part2.zip** decompression: 7-zip is recommended ([https://7-zip.org/](https://7-zip.org/)) Image re-export: StreamPix10 can be used to open .seq files ([https://www.norpix.com/products/streampix/streampix.php](https://www.norpix.com/products/streampix/streampix.php)) ## Author Info Author: Ian Wells Point of Contact: Professor Jacob Leachman, [jacob.leachman@wsu.edu](mailto: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).