A Fluid Flow Analysis for Convective Thermal Control of Flight Experiments

A method for thermally analyzing convectively cooled flight experiments is presented in this paper. A three-dimensional fluid flow analysis code was used to optimize air circulation patterns and predict air velocities in thermally critical areas. A comparison between a fan flow analysis using this code and the performance characteristics of a typical isothermal free jet was made. The velocity profiles and radial distribution agree well for downstream mixing of the flow. Predicted air velocities from the fluid analysis were used to calculate forced convection coefficients for the flight experiment. These convection coefficients were used in a finite difference thermal analysis code to describe the response of air temperature and heat loss for the LIDAR Atmospheric Sensing Experiment (LASE) during transient flight profiles. The performance of the existing thermal design is described and the analytical techniques used to arrive at this design are presented. Based on experience gained from LASE, several recommendations are made for the future design of convectively cooled flight experiments.