In order to the problem of short life of air filter in intake system due to the harsh working conditions of commercial vehicles(CV), the computational fluid dynamics (CFD) method was used to simulate the velocity flow field of the three high inlet pipe assemblies, and the velocity cloud of different vortex fan angle were obtained. These velocity cloud diagram proves that the velocity gradient is caused by the angle of the vortex fan, and the velocity gradient can coarsely separate the dust, droplet and gas. The rack experiment method was adopted for the three high inlet pipe assemblies to evaluate its the pre-filter performance. The test results show that the vortex fan at the front end of the tube plays a good role in the pre-filtration of dusts and droplets. And the pre-filtration efficiency reaches over 87%. Effectively extend the life of the air filter element.
The outside rear-view mirror (OSRVM) is installed on the vehicle’s surface, which causes unwanted aerodynamic noise and wind drag during driving. It is important to use simulation methods to predict the performance of aerodynamic noise and wind drag of commercial vehicles due to the OSRVM. Considering the wind drag of the OSRVM, a combinational simulation strategy is employed to calculate external flow and interior acoustic fields of commercial vehicles, respectively. The flow field is computed a priori with an incompressible flow solver. The acoustic field was then computed based on the information extracted from the CFD solver. To obtain the interior noise level at the driver’s ears, a vibroacoustic model is used to calculate the response of the window glass structure and interior cavities, where the unsteady aerodynamic pressure loading on the two side windows’ surface is treated as the acoustic source field. The paper provides flow field and acoustic simulations for three OSRVM configuration models. The results are compared to data obtained in road sliding test measurement on the commercial vehicle. The accuracy of the hybrid simulation method is proved, and the comparative analyses verify that the OSRVM B model dramatically reduces the interior noise and wind drag of commercial vehicles.
In order to mitigate the adverse effects of cathode gas pressure fluctuations on the lifetime of a proton exchange membrane fuel cell (PEMFC), a model of a cathode supply system with a bypass valve structure was developed, and a pressure cooperative control strategy was established based on this structure. Bench tests have verified that the proposed structure and control strategy has a good control effect on the sudden pressure change. Pressure fluctuations can be controlled to around 50Pa under the step conditions used in the test, and the absolute value of the pressure inside the pipeline can be controlled to the preset target, which helps to improve the life of the stack.
Aiming at the problem of matching fan noise and heat dissipation in a commercial vehicle cooling system, it is proposed to reduce noise by changing the fan structure and to increase the windshield to block the hot air reflux. By changing the number of blades, wheel hub ratio, blade bending angle fan performance parameters, and the cooling fan mass flow rate and aerodynamic noise were simulated by CFD, the fan performance parameters were optimized. Then, the flow field and temperature field of engine cabin are analyzed. According to the analysis, the hot air reflux exists in the radiator, and the baffle is added to the upper part of the radiator and to the left and right sides of the radiator to block the reflux. The results show that the fan noise is reduced by 2.7 dB and the maximum temperature in the engine cabin is reduced from 417k to 392k.
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