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International Journal of Automotive Technology, Vol. 10, No. 5, pp. 561566 (2009) DOI 10.1007/s1223900900656
2) Department of Mechanical Engineering, Pohang University of Science and Technology, Gyeongbuk 790-784, Korea (Current Address; Pusan National University)
Department of Mechanical Engineering, Pohang University of Science and Technology, Gyeongbuk 790-784, Korea
(Received 31 October 2008; Revised 2 March 2009)
ABSTRACTAir flow inside an automotive HVAC module was visualized using a high-resolution PIV technique with varying temperature control modes. The PIV (particle image velocimetry) system used for the experiment consisted of a 2-head Nd:YAG laser (125 mJ), a high-resolution CCD camera (2 K 2 K), optics and a synchronizer. A real automotive HVAC module was used as a test model, and some of its casing parts were replaced with transparent windows to capture the flow images of the laser-light-sheet illumination. In addition, instant velocity fields were measured for three different temperature control modes by adjusting the temperature baffle. Characteristics of the air flow inside the automotive HVAC were then evaluated based on the time-averaged PIV data. Results from the experiment showed that flow for the warm mode loses more momentum due to its complicated flow path. Thus, the present PIV data can be used to validate numerical prediction and to improve the performance of HVAC modules.
KEY WORDS : HVAC, PIV, Temperature baffle, Bi-level mode, Flow visualization
1. INTRODUCTION
An automotive HVAC (heating ventilating and air conditioning) system is an indispensable device for controlling temperature, humidity and air ventilation inside the passenger area. To improve the performance of an HVAC system as well as thermal comfort, a deeper understanding of the characteristics of the air flow inside the HVAC system is required. Recent advancements in computational fluid dynamics and experimental diagnostic techniques make it easy to analyze the climatic environment inside a vehicle.In an automotive HVAC module, the temperature baffle controls the temperature in the passenger area by changing the direction of air flow.
The high-speed air coming from a sirocco-fan does not easily pass through the HVAC module because of the temperature control baffles, which curve the flow pathway, and the heat exchanger. Because the air flow inside anHVAC module has three-dimensional characteristics, it is therefore not easy to measure it experimentally. Hence, most previous studies for HVAC modules were...