Date of Award


Document Type

Master's report

Degree Name

Master of Science in Mechanical Engineering (MS)

College, School or Department Name

Department of Mechanical Engineering-Engineering Mechanics


Jeremy J. Worm


Accurately predicting component temperatures, and the influence various subsystems have on each other prior to hardware development and testing is an important aspect of the vehicle development process. In this report, a 1-D thermal model is used for predicting the behavior of the exhaust system and underbody area of prototype Hybrid Electric HMMWV XM1124. This prototype vehicle is designed to be capable of exporting up to 15 kW of electrical power to a micro-grid or similar operation. However, in this project instead of exporting power to a micro-grid, 6.5 kW of power was used to charge the batteries and increase the SOC of the battery in standstill condition. This usage scenario results in moderately high engine loads with zero air velocity under the vehicle, leading to potentially extreme underbody temperatures. The thermal modeling of the exhaust system and the vehicle underbody is done using the RadTherm software by ThermoAnalytics Inc.

The 1-D thermal modeling tool was used to predict the surface temperature of the exhaust system, underbody surface temperature, and in-cabin floor temperature. The model was calibrated with experimental data providing the appropriate boundary conditions. Validation of the RadTherm model is done by instrumenting the vehicle with thermocouples and measuring temperatures at various points along the exhaust system and vehicle underbody sheet metal. These experimental values are then compared with the values predicted by RadTherm. The calibrated and validated model can be used as a tool to identify potential hot spots in the system to strategically design and place heat shields. This report will describe the details around the development, calibration, and experimental validation of the model.