The transient performance of a twophase fluid reservoir
Abstract
Thermal control of future large, high power spacecraft will require a twophase fluid central bus. The twophase fluid reservoir is a critical component in the twophase fluid bus. It both controls the saturation temperature and provides a space for volumetric changes. A dynamic reservoir simulation model does not currently exist, but it is needed to expedite efforts and reduce risk. During 1989 an effort was made to develop a simulation model of the transient performance of a twophase fluid reservoir. As a beginning, a preliminary model was developed. It is based upon component mathematical models in lumped parametric form and build upon five component mathematical models for calculating dynamic responses of twophase fluid reservoirs, primary feedback elements, controller commands, heater actuators, and reservoir heaters. As much as possible, the model took advantage of the available SINDA'85/FLUINT thermal/fluid integrator. Additional calculation logic and computer subroutines were developed to complete implementation of the model. The model is capable of simulating dynamic response of an equilibrium twophase fluid reservoir. Modification of the model to include the liquid/vapor nonequilibrium is required for applications of the model to simulate performance of reservoir in which the liquid and vapor phases of the reservoir fluid are not in equilibrium. In addition, the model in its present form, needs to be refined in several respects. More empirical data are needed to guide the model development. The model may then be used to conduct a full parametric study of twophase fluid reservoirs. More complexities in twophaes flow regions in laboratory and flight conditions may have to be considered eventually if empirical data cannot be simulated satisfactorily. System with other components arrangement also need to be simulated if optimization is ever to be attained. The present model does, however, preliminarily demonstrates that such analyses are quite possible and offers a far less expensive method to understand the transient of a twophase fluid reservoir system than a totally headware approach.
 Publication:

1989 NASAASEE Summer Faculty Fellowship Program in Aeronautics and Research
 Pub Date:
 September 1989
 Bibcode:
 1989asee.nasa...30C
 Keywords:

 Aerospace Vehicles;
 Computerized Simulation;
 Dynamic Response;
 Large Space Structures;
 LiquidVapor Equilibrium;
 LiquidVapor Interfaces;
 Mathematical Models;
 Reservoirs;
 Temperature Control;
 Actuators;
 Controllers;
 Feedback;
 Flight Conditions;
 Heaters;
 Integrators;
 Optimization;
 Risk;
 Fluid Mechanics and Heat Transfer