Research On Heat Transfer Characteristics Of Condensers Under Various Gravity Condition

With the rapid development of the aerotechnics, high-power onboard electronics equipments are widely used. In order to meet the higher cooling requirements of aircraft environmental control systems and aerospace thermal manage and life support systems, the research of airborne vapor cycle cooling systems and condensing systems is of great interest. In this paper, theoretical research and simulation on heat transfer characteristic of condensing heat transfer and condenser design under various gravity is conducted.In this work, condensation in tube heat transfer characteristics and flow pattern under various gravity is reviewed, the calculation formula of R134a's thermophysical properties are collected, condensation heat transfer mathematical models under microgravity, reduced gravity, and high gravity are established. Based on the mathematical models, a computer program for the condenser design is developed. Comparing the calculated data to the experimental data, the mathematical model is proved to be reliable.The mathematical model calculation results show that gravity has remarkable effects on heat transfer and pressure drops in condensers. With the vertical gravity force, the condenser performances become better in some extent. If gravity is opposite to the flow direction, the pressure drop increases with the gravity increasing, and the heat transfer depends.