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기술보고서

기술보고서 게시판 내용
타이틀	Liquid Acquisition Device Design Sensitivity Study
저자	VanDyke, M. K.;; Hastings, L. J.
Keyword	GRID GENERATION (MATHEMATICS); INTERFACIAL TENSION;; LIQUID ROCKET PROPELLANTS;; MATHEMATICAL MODELS;; MECHANICAL DEVICES;; MICROGRAVITY;; PRESSURE DROP;; PROPULSION SYSTEM CONFIGURATIONS;; REGRESSION ANALYSIS;; SENSITIVITY ANALYSIS;; STORABLE PROPELLANTS;; VANES;; WIRE
URL	http://hdl.handle.net/2060/20130000453
보고서번호	NASA/TM-2012-217473
발행년도	2012
출처	NTRS (NASA Technical Report Server)
ABSTRACT	In-space propulsion often necessitates the use of a capillary liquid acquisition device (LAD) to assure that gas-free liquid propellant is available to support engine restarts in microgravity. If a capillary screen-channel device is chosen, then the designer must determine the appropriate combination screen mesh and channel geometry. A screen mesh selection which results in the smallest LAD width when compared to any other screen candidate (for a constant length) is desirable;; however, no best screen exists for all LAD design requirements. Flow rate, percent fill, and acceleration are the most influential drivers for determining screen widths. Increased flow rates and reduced percent fills increase the through-the-screen flow pressure losses, which drive the LAD to increased widths regardless of screen choice. Similarly, increased acceleration levels and corresponding liquid head pressures drive the screen mesh selection toward a higher bubble point (liquid retention capability). After ruling out some screens on the basis of acceleration requirements alone, candidates can be identified by examining screens with small flow-loss-to-bubble point ratios for a given condition (i.e., comparing screens at certain flow rates and fill levels). Within the same flow rate and fill level, the screen constants inertia resistance coefficient, void fraction, screen pore or opening diameter, and bubble point can become the driving forces in identifying the smaller flow-loss-to-bubble point ratios.