HokieSat Thermal System Michael Belcher Thermal Lead December 11, 2002.

Presentation on theme: "HokieSat Thermal System Michael Belcher Thermal Lead December 11, 2002."— Presentation transcript:

HokieSat Thermal System Michael Belcher Thermal Lead December 11, 2002

Introduction Thermal modeling Software Calculations Results from analysis Conclusions Future plans

Heat Transfer Fundamentals Convection Q = h convection A(  T) Conduction Q = G(  T) Radiation Q =  A  (T 2 4 -T 1 4 ) Heat transfer in space occurs through conduction and radiation only

Thermal Model Predicts temperatures of spacecraft components Identifies problem areas Useful in analyzing existing design Usually software based TSS, SINDA, TRAYSIS, SSPTA, I-DEAS

SSPTA Simplified Space Payload Thermal Analyzer Evaluation/ Educational Software from Swales Aerospace Consists of several smaller programs, which calculate view factors, radiation couplings, absorbed heat loads Used in conjunction with SINDA

SINDA Systems Integrated Numerical Differential Analyzer Freeware Calculates temperatures based on a network of thermal nodes Solves network using finite difference method

SSPTA Models

Conduction Couplings Calculated in Excel Q = G(  T) G = hA Value of h dependant upon: Interface type Conduction coefficient

Conduction Couplings

Thermal Models Created separately for independent verification and ease of use Stand-alone models Battery box CEE External Integrated model Internal, external, battery box, CEE

Hot and Cold Case Parameters

Model Results: CEE Preliminary results showed need for a thermal filler around bolted interfaces

Overall Model: Cold Case

Overall Model: Hot Case

Parametric Study: Battery Box Assumed thermal filler (h = 14000 W/m 2 °C) used at bolted interface between battery box frame and nadir panel

Parametric Study: Effect of h Assumed h = 1000 W/m 2 °C at all bolted interfaces Variance of less than ±2 °C in most component temperatures In general, the variance indicated that a lower value of h is conservative

Plans Verify G’s with CEE, battery box testing Study effects of MLI Procure interface materials (indium tape) Examine possibility of heater control for cold components Study survival and shuttle bay environments

Recap Thermal models Results from models Parametric studies Future plans

Conclusions Detailed thermal model of HokieSat has been generated and tested Additional analyses are necessary Verification of model with test data desired Some changes to the thermal design are required

Download ppt "HokieSat Thermal System Michael Belcher Thermal Lead December 11, 2002."

Similar presentations