| Popis: |
High energy pulsed power systems involve components that generate varied degrees of heat loads, from as low as a few kW (power generator) to as high as a few MW (pulsed power source). When there is a restriction on the payload mass and volume, it becomes imperative to look for a Thermal Management System (TMS) that would suitably accommodate the wide spectrum of heat loads. This problem becomes even more acute when the power system is aircraft-related. Localized, very high-flux heat loads (as in a pulsed power source) necessitate the use of specialized cooling methods such as sub-cooled boiling that combines the benefits of high heat flux with single phase forced convection. A general thermodynamic, analytical investigation was conducted to determine the impact of thermal management related conceptual improvements on the overall performance of an aircraft-based high pulsed power system. In earlier investigations of cooling schemes for pulsed power as well as high power laser systems, two arrangements were considered: (i) a “no” tank model with a ram air heat exchanger (RAHX) operating only when the heat load was on (peak load); and (ii) a “two” tank model with the RAHX operating either intermittently, only when the heat load was turned off, or continuously at an average heat load. In the current study, a cooling scheme based on the “no” tank model aims to achieve complete cooling at the end of the duty cycle (DC) by continuously circulating the coolant in the plumbing through the RAHX, thus: when the heat source is active, the coolant acquires the waste heat, and rejects only a part of it in the RAHX to the ambient air, resulting in a rise in the coolant temperature; when the heat source is turned off, the relatively hot coolant continues to cycle through the RAHX to cool it back to the starting condition, so that it would be ready for the next duty cycle. Necessary flow and geometric conditions to achieve this goal have been derived, and the corresponding results are presented here. |
