Selection and Thermal Modeling of an Automotive Blower Motor by Using CFD and Its Experimental Validation 2018-01-0073

The present paper outlines the selection and numerical modeling of a high performance and efficient blower motor fitted in an automotive Heating ventilation and air conditioning (HVAC) system. In today’s scenario blower motor is present in almost every car whether fitted with AC system or only blower system. The selection of a blower motor is very important in terms of delivering right amount of airflow with minimum consumption of electric power. As the power consumption goes up it may impacts in indirect green house gas (GHG) emission from a vehicle. While it does so e.g. fulfills HVACs’ airflow need, it generates some amount of heat which is very detrimental for its life and overall performance as well. Also the generated heat may lead to increase in temperature of the main stream air flow causing reduction in the cabin cooling and eventually hampers the comfort level.

The present study describes the methodology of selecting an automotive blower motor and its thermal modeling by using computational fluid dynamics (CFD). It involved the two different alternative methods of selecting the motor with the help of motor characteristics, fan characteristics and system resistance. The later method was adopted in selecting the motor in current study while the system resistance was evaluated numerically. Motor torque was estimated and electric power consumption was derived. Further to this the motor was modeled in CFD in detailed with its internal components like brush, commutator, armature etc. and then airflow and thermal analysis were carried out by conjugate heat transfer. Heat generated by the motor was modeled by source term. A detailed investigation in terms of airflow and temperature distribution was carried out to figure out the motor temperature rise. The simulation results was validated with that of experimental results and found a good correlation. Thus a methodology is developed with which designer can select and package the motor in order to have minimum power consumption and maximum life.