Model results of optimized convex shapes for a solar thermal rocket thruster
- Sparta Inc., Edwards AFB, CA (United States). Phillips Lab.
A computational, 3-D model for evaluating the performance of solar thermal thrusters is under development. The model combines Monte-Carlo and ray-tracing techniques to follow the ray paths of concentrated solar radiation through an axially symmetric heat-exchanger surface for both convex and concave cavity shapes. The enthalpy of a propellant, typically hydrogen gas, increases as it flows over the outer surface of the absorber/exchanger cavity. Surface temperatures are determined by the requirement that the input radiant power to surface elements balance with the reradiated power and heat conducted to the propellant. The model uses tabulated forms of surface emissivity and gas enthalpy. Temperature profiles result by iteratively calculating surface and propellant temperatures until the solutions converge to stable values. The model provides a means to determine the effectiveness of incorporating a secondary concentrator into the heat-exchanger cavity. A secondary concentrator increases the amount of radiant energy entering the cavity. The model will be used to evaluate the data obtained from upcoming experiments. Characteristics of some absorber/exchanger cavity shapes combined with optionally attached conical secondary concentrators for various propellant flow rates are presented. In addition, shapes that recover some of the diffuse radiant energy which would otherwise not enter the secondary concentrator are considered.
- OSTI ID:
- 116230
- Report Number(s):
- CONF-950336-; ISBN 0-7918-1300-2; TRN: IM9545%%197
- Resource Relation:
- Conference: American Society of Mechanical Engineers/Japanese Society of Mechanical Engineers/Japan Solar Energy Society international solar energy conference, Lahaina, HI (United States), 19-24 Mar 1995; Other Information: PBD: 1995; Related Information: Is Part Of Solar engineering 1995: Proceedings. Volume 2; Stine, W.B. [ed.] [California Polytechnic Univ., Pomona, CA (United States)]; Tanaka, Tadayoshi [ed.] [Electrotechnical Lab., Ibaraki (Japan)]; Claridge, D.E. [ed.] [Texas A and M Univ., College Station, TX (United States)]; PB: 582 p.
- Country of Publication:
- United States
- Language:
- English
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