A Predictive Bubble Point Pressure Model for Porous Liquid Acquisition Device Screens

Hartwig, Jason; Mann, J. Adin

doi:10.1615/jpormedia.v17.i7.30

Cited by 35 publications

(25 citation statements)

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“…The second finest 450x2750 mesh produced the highest bubble points, for both GHe and GH 2 . The 510x3600 mesh outperformed the 325x2300 mesh at LH 2 temperatures, but the 325x2300 yielded higher pressures in room temperature liquids [11,12]. The reason for this crossover in performance is due to the temperature dependence of the screen pore diameter, as mentioned previously.…”

Section: Liquid Hydrogen Testsmentioning

confidence: 57%

“…The bubble point is defined as the differential pressure across a LAD screen pore that overcomes the surface tension forces at that pore. Bubble point pressure is proportional to the surface tension of the liquid and inversely proportional to the effective screen pore diameter, as derived in Hartwig and Mann [11,12] and shown in Eq. 1:…”

Section: The Bubble Point Pressurementioning

confidence: 88%

“…Pore sizes for 325x2300 (12795 warp and 90551 shute wires per meter), 450x2750 (17716 warp and 108268 shute wires per m), and 510x3600 (20079 warp and 141732 shute wires per meter) Dutch Twill were determined in room temperature tests [11,12]. The exact same samples were used here for heated pressurant gas tests in cryogenic liquids.…”

Section: Experimental Designmentioning

confidence: 99%

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Warm Pressurant Gas Effects on the Static Bubble Point Pressure for Cryogenic LADs

Hartwig

McQuillen²,

Chato³

2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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This paper presents experimental results for the liquid hydrogen and nitrogen bubble point tests using warm pressurant gases conducted at the NASA Glenn Research Center. The purpose of the test series was to determine the effect of elevating the temperature of the pressurant gas on the performance of a liquid acquisition device (LAD). Three fine mesh screen samples (325x2300, 450x2750, 510x3600) were tested in liquid hydrogen and liquid nitrogen using cold and warm non-condensable (gaseous helium) and condensable (gaseous hydrogen or nitrogen) pressurization schemes. Gases were conditioned from 0K -90K above the liquid temperature. Results clearly indicate degradation in bubble point pressure using warm gas, with a greater reduction in performance using condensable over non-condensable pressurization. Degradation in the bubble point pressure is inversely proportional to screen porosity, as the coarsest mesh demonstrated the highest degradation. Results here have implication on both pressurization and LAD system design for all future cryogenic propulsion systems. A detailed review of historical heated gas tests is also presented for comparison to current results. Nomenclatured shute = Diameter of the shute wire [μm] d warp = Diameter of the wap wire [μm] D p = Effective pore diameter [μm] g = Gravitational acceleration [m/s 2 ] HEX = Heat exchanger LL = Liquid Level above LAD screen [m] l s = Distance between consecutive shute wires [μm] n shute = Number of shute wires per inch of screen [1/m] n warp = Number of warp wires per inch of screen [1/m] PCA = Pressure control assembly t = Screen thickness [μm] ΔP BP = Bubble point pressure [Pa] ΔT = Temperature difference between liquid and pressurant gas [K] ε = Porosity γ = Surface tension [mN/m] ρ LH2 = Liquid hydrogen density [kg/m 3 ] θ c = Contact angle [degrees]

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Section: Liquid Hydrogen Testsmentioning

confidence: 57%

Section: The Bubble Point Pressurementioning

confidence: 88%

Section: Experimental Designmentioning

confidence: 99%

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Warm Pressurant Gas Effects on the Static Bubble Point Pressure for Cryogenic LADs

Hartwig

McQuillen²,

Chato³

2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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“…Hartwig and Mann outlined a simplified bubble point model from the general Young–LaPlace equation for the pressure drop across a three‐dimensional (3‐D) curved interface

Δ P_{BP} = \frac{4 γ_{LV} \cos θ_{C}}{D_{normalp}}

where

Δ P_{BP}

is the measured bubble point pressure, which is then taken as the differential pressure across the screen the moment when vapor penetrates a liquid laden porous screen,

γ_{LV}

is the liquid/vapor (L/V) surface tension,

θ_{C}

is the advancing contact angle between screen pore and liquid, and D p is the effective pore diameter, which is fit to

\frac{1}{D_{normalp}} = \frac{1}{R_{max}} + \frac{1}{R_{min}}

where

R_{\max}

and

R_{\min}

are the principle radii of curvature at the L/V surface.…”

Section: Bubble Point Modelmentioning

confidence: 99%

“…The effective pore diameter can be estimated through reference fluid bubble point tests (method 1), through historical bubble point data (method 2), or through scanning electron microscopy (SEM) analysis (method 3). Method 2 may be best despite added uncertainty in summing over all reported values, as summing over historical data takes into account sample to sample variations during screen manufacturing (Hartwig and Mann) . To make pretest predictions for a given LAD sample, obviously the best predictive tool is to conduct a reference fluid bubble point test for that exact sample, as in method 1.…”

Section: Bubble Point Modelmentioning

confidence: 99%

Bubble point pressures of binary methanol/water mixtures in fine‐mesh screens

Hartwig

Mann

2013

AIChE Journal

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Binary methanol/water mixture bubble point tests involving three samples of fine-mesh, stainless steel screens as porous liquid acquisition devices are presented in this article. Contact angles are measured as a function of methanol mass fraction using the Sessile Drop technique. Pretest predictions are based on a Langmuir isotherm fit. Predictions and data match for methanol mole fractions greater than 50% when pore diameters are based on pure liquid tests. For all three screens, bubble point is shown to be a maximum at a methanol mole fraction of 50%. Model and data are in disagreement for mole fractions less than 50%, which is attributed to variations between surface and bulk fluid properties. A critical Zisman surface tension value of 23.2 mN/m is estimated, below which contact angles can be assumed to be zero. Solid/vapor and solid/liquid interfacial tensions are also estimated using the equation of state analysis from Neumann and Good.

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Investigation on Wicking Performance of Cryogenic Propellants Within Woven Screens Under Different Thermal and Gravity Conditions

Xie

et al. 2020

J Low Temp Phys

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A Predictive Bubble Point Pressure Model for Porous Liquid Acquisition Device Screens

Cited by 35 publications

References 0 publications

Warm Pressurant Gas Effects on the Static Bubble Point Pressure for Cryogenic LADs

Warm Pressurant Gas Effects on the Static Bubble Point Pressure for Cryogenic LADs

Bubble point pressures of binary methanol/water mixtures in fine‐mesh screens

Investigation on Wicking Performance of Cryogenic Propellants Within Woven Screens Under Different Thermal and Gravity Conditions

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