Research On The Influence Of The Setting Of Car Skylight On The Cabin Comfort

With the continuous development of science and technology,consumers’ requirements for the comfort and safety of cars have been continuously improved.Drivers who drive in high temperature and confined space for a long time are prone to be mentally depressed,sleepy and inattentive,which is also the root cause of traffic accidents and will greatly reduce the experience of passengers.The car sunroof has become one of the necessary configurations for consumers when purchasing cars.This configuration can greatly improve the air flow performance in the cabin and optimize the internal environment of the car.A reasonable skylight structure can improve the airflow field in the cabin,improve the ventilation effect,reduce noise and wind resistance,and improve driving comfort and safety.This paper mainly studies the influence of skylight design on the flow field in the cabin,and improves the air flow performance in the cabin by changing the size,position and structure design of the skylight.In this paper,the three-dimensional model is established by referring to the design dimensions of the real vehicle,and the numerical simulation analysis of the flow field in the vehicle when the sunroof is opened is carried out by using the fluid simulation software.Combined with the method verified by the real vehicle road experiment,the feasible and effective optimization and improvement measures are output.The main research contents are as follows:(1)Based on the design parameters of a vehicle model,the 3D model of the vehicle is established by using CATIA software.The model is modified and simplified through simulation analysis and model verification.(2)The 3D model is imported into the ANSYS workbench for grid division and fluid domain setting,and the flow field in the cabin is simulated and analyzed under the clear boundary conditions when the sunroof is open.Four monitoring points are set in the model to detect the collected air velocity and sound pressure level value and analyze the existing improvement points.(3)Based on the analysis of simulation results,the skylight structure is optimized and three optimization schemes are output: 1)optimize the skylight size;2)Add deflector;3)Optimize the sunroof layout.(4)The models of three different optimization schemes are simulated and analyzed respectively to study the influence of the flow field in these three optimization schemes under vehicle driving conditions.(5)Based on the simulation results,the pressure,flow velocity and wind vibration sound pressure level of each monitoring point inside the vehicle after adding the deflector are verified through the actual vehicle road test.The optimization scheme with obvious output effect is to add the deflector design.Through the above analysis and optimization comparison,when adding a deflector with parameter values of H=105mm and L=550mm,and an inclination angle of 45 °,the flow velocity of the drainage basin at point B of the air flow area in the car cabin is0.33493m/s,and the pressure value is-637.393 Pa,which is 20% higher than the air flow velocity of 0.279293m/s before the sunroof is not optimized,and the pressure increase change is not significant;The flow velocity and pressure values of the watershed at point D are 0.30362m/s and-739.432 Pa,respectively.Through observation,it was found that the flow velocity of the second row of air inside the cabin is relatively uniform,and the flow velocity values in the upper and lower areas are similar.This indicates that the area has high flowability and stable temperature control.Through experimental analysis,it can be seen that the optimized noise amplitude has decreased by about 5.5d B compared to the initial state,and the wind vibration phenomenon of the sunroof has basically disappeared.The addition of a deflector has a significant impact on the air flow and noise improvement inside the cabin.