Validation of a Thermal Management Concept for the Avionics Compartment of a Stratosphere HALE

Abstract

This Paper presents several parts of thermal testing activities around the High AltitudePlatform (HAP). HAP is classified as an unmanned air vehicle and is intended to carry out research flights in the stratosphere. To this end, HAP has several measuring systems that are capable of conducting ground and environmental research. Special models and methods are being developed at the German Aerospace Centre (DLR). The German Aerospace Centre is actively developing specialized simulation-based models of the HAP that support its development. One of the challenges here is to predict thermal effects for the components used in order to improve HAP's reliability during test flights. Simplified test setups of the individual avionic components are carried out on the ground to better assess its thermal models. Previously carried parameter studies are validated and failures in extreme situations are ruled out. In order to generate preliminary study results for the flight at an altitude of 20 kilometers, a series of tests were carried out in a specially designed vacuum chamber. These are carried out in different environmental conditions and should be able to make certain statements for both day and night flights. In addition, the boundary conditions are given by the minimum and maximum temperatures. Ultimately, the outcome of the thermal analysis will serve as the basis for the subsequent development of the HAP and its first flight.