Investigation on the Effects of Intake Grill in the Performance of Cooling Module Under Vehicle Working Conditions

Air path model of cabin for cooling module simulation for vehicle has been constructed according to the test, and the simulation results were compared with the test data to verify the authenticity of the module. This simulation model provides an effective platform for vehicle thermal management analysis. The module is used to simulate the different intake grills and to find how different grills affect the performances of the cooling module. The intake grill effect significantly influences the performance of airflow into the cabin. Keywords: Cooling module, Intake grill, Simulation, Vehicle. 1. INTRODUCTION The shape of the front car on one hand, determines the airflow of cabin and pressure effective for the frontal area, and on the other hand, it is the starting point for interior flow field of the cabin. Therefore, it affects the aero-dynamics of the cabin. As it is known, the internal flow situation of the cabin is extremely complex, and subtle changes in structural characteristics of the entire flow field have a great impact on the cooling module. However, the cooling module of the cabin makes the work environment complex [1-3]. 2. SIMULATION 2.1. Engine Input Dates The parameter of engine is used as shown in Table 1. It is determined by the heat balance test and the drag test in vehicle working for the energy distribution of combustion to measure the temperature of coolant as shown in Fig. (1). Fig. (1). The engine heat map for cooling system. *Address correspondence to this author at the FAW CAR Co. Ltd. Chang Chun, China; Tel: 0431-13944836786; Fax: 0431-81504449; E-mail: [email protected] Table 1. The engine main date. Engine Main Date Displacement: 2.0T Power: 120kW Cylinder: 4 Rated: 6000r/min Cooling module input dates are shown in Table 2. Table 2. Cooling module input date. Cooling Module Input Date 1 Coolant: Water / glycol 2 The pump curve 3 Fan characteristic curve 4 Condenser heat transfer curve 5 Cooling system pressure 6 Radiator heat transfer curve 7 Radiator air resistance curve 8 Condenser resistance curve 9 CAC resistance curve 10 CAC heat transfer curve 2.2. Cabin Air Path Model Input Dates By the CFD instead of the wind tunnel, air characteristic parameters are obtained, which help in building the KULI as shown in Figs. (2, 3) [4, 5]. 122 The Open Mechanical Engineering Journal, 2014, Volume 8 Chang et al. Fig. (2). The cabin CFD result. Fig. (3). Air path model of cabin for cooling module. The model of cooling module for heat balance test is shown in Fig. (4). Steady simulation is maintained at a temperature of 35°C, with the cooling fan running at full rotation, and the vehicle being at a speed of 40km/h. 3. VERIFICATION AND ANALYSIS The simulation results are compared with the test data, as shown in Figs. (5, 6) and the error of 5% within, is caused by the very complex flow field in the cabin. There is heat reflux in a part of the cooling module making simulation difficult. The model for cooling system can predict and analyze the performance of the cooling system. 3.1. Analysis Intake Boost Coefficient CP According to the Bernoulli's equation of fluid mechanics, when the air flows through the grill, suddenly the crosssection becomes smaller [6, 7]. There is a high-pressure zone near the cabin outside. So, the outside pressure of cabin is higher than the inside pressure. It is much easier for air to flow smoothly into the cabin. This phenomenon is defined as the intake inertia, which expresses an intake boost coefficient CP. The grill surface of measured pressure value is converted to the form of the pressure coefficient Cp. CP = P / (0.5 * ρ * V) (1) where P is the pressure near the intake grill, ρ is the air density and V is the vehicle speed. Fig. (12) shows the fan load of 100% signifying the relationship between the boost coefficient CP and vehicle speed. Fig. (4). Cooling module heat transfer model. Investigation on the Effects of Intake Grill The Open Mechanical Engineering Journal, 2014, Volume 8 123 Fig. (8). The intake boost coefficient CP. This paper focuses on the typical operating conditions of the vehicle at low speed and high torque engine under load on the cooling module performance analysis and calculation of 3 cases of intake grills as shown in Fig. (7). Fig. (9). The intake boost coefficient CP. By the CFD, the CP is obtained as shown in Fig. (8). CASE 1: the upper grill to modify the angle of the wind guide. CASE 2: at lower opening, the upper grill styling changes. 0.5965