Accession Number : ADA303215

Title :   Vehicle Thermal Control with a Variable Area Inlet.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING

Personal Author(s) : Layne, Thomas R.

PDF Url : ADA303215

Report Date : DEC 1995

Pagination or Media Count : 109

Abstract : This study developed a variable area inlet and controller that regulated the temperature of an electrical component with ram air. The intent of the variable area inlet was to reduce vehicle drag by eliminating inefficiencies associated with component cooling and fixed area inlets. These inefficiencies arise from vehicles moving at varying speeds through varying air temperatures. The hardware model consisted of an electrical component mounted inside a right-circular cylindrical duct. The variable area inlet, mounted in the front of the duct, consisted of a butterfly valve that was actuated by a stepper controller acted on the feedback signal of a thermocouple that was mounted on the electrical component. The system was successful in regulating the component temperature. A nonlinear simulation model was built and the thermal plant in the simulation was based on the electrical components empirically derived Nusselt number. Proportional, Proportional-Derivative (PD), and Proportional-Integral-Derivative (PID) controllers were built and tested. The PD and PID controllers did not appear to need any gain scheduling for the varying speed and temperature conditions. Lastly, a general design process was detailed. (AN)

Descriptors :   *TEMPERATURE CONTROL, *CONVECTION(HEAT TRANSFER), *AIR COOLED, VELOCITY, MATHEMATICAL MODELS, COMPUTERIZED SIMULATION, OPTIMIZATION, COMPUTER AIDED DESIGN, AIR FLOW, THESES, RADIATIVE TRANSFER, VARIATIONS, NONLINEAR SYSTEMS, TEMPERATURE GRADIENTS, THERMAL ANALYSIS, FEEDBACK, AIRSPEED, CONTROL THEORY, DRAG, FREE STREAM, SURFACE TEMPERATURE, CONDUCTION(HEAT TRANSFER), INLETS, THERMOCOUPLES, HEAT SINKS, CLOSED LOOP SYSTEMS, HEAT LOSS, HEAT TRANSFER COEFFICIENTS, LAPLACE TRANSFORMATION, VENTILATION DUCTS.

Subject Categories : Air Condition, Heating, Lighting & Ventilating
      Thermodynamics
      Jet and Gas Turbine Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE