Preliminary Experimental Validation of a Car Cabin Model for Climate Control 970530

This paper is dedicated to a complete car cabin model for climate control and the expected experimental validation based on a comparison between wind tunnel tests and calculation results. Climate control system developments have to be improved in terms of time and quality by introducing calculation tools during project phases. This approach is related to some others presented the last two years (SAE papers Nos. 950019, 960813, 960961). SAE papers No. 960961 specifically presented a new meshing tool for car cabin geometry and its place in HVAC system development. In addition to this unusual, but powerful method of meshing, a new calculation tool «ACOZ» (flow, convection, conduction and radiations) has to be validated before being used in a real project. This validation is composed of three major parts.

The first part is the meshing work based on a CAD-CATIA file treated with «Maille» through IGES transfert, with its major functionality (anamorphic stretching). The boundary conditions used for calculation are also explained. Then the different phases of methods are described to handle stationary and transient analysis, and are illustrated by some representative results related to winter conditions.

The second part is dedicated to experimental work based on measurements done in the climatic wind tunnel tests. Measurement methods and conditions applied to the car are described after a short description of the wind tunnel. Experimental results are presented in respect with two major conditions summer (tests for AC unit) and winter (tests for heating unit).

The third part establishes comparison between experimental and calculation results in order to validate the model. It also discusses the main assumptions done for the calculations and criticizes the method of measurements.

The conclusion will explain the next step to be performed and how these methods of simulation could help in estimating performance of a climate control system within a development program. Some relevant links with additional existing models acting in complementary fields are also quoted.