Study Of Parking Ventilation Cooling Characteristics Of Cars And Optimization Of Thermal Environment

In the typical summer climate of southern China,the car is parked in the open parking lot,and the thermal environment inside the passenger compartment is very bad after the sun exposure.At the time,turning the car air conditioning system immediately will not only cause damage to the engine,but also stop the release of the harmful substances in the passenger compartment.It will be harmful to the passenger.Thus,it is meaningful to study on the thermal environment of the passenger compartment under parking.The main work of this paper is as follows:At the beginning,by analyzing the computational fluid dynamics and occupant compartment heat transfer theories,simplified the geometric model of the occupant compartment and established a mesh model,and had a mesh irrelevance check.Then we set the corresponding boundary conditions with the influence of solar radiation.we selected six monitoring points to analyze the transient temperature changes,which had influence on occupant thermal comfort.Then,By comparing the ventilation areas under natural ventilation cooling condition,we proposed a method about the forced ventilation scheme for the top of the passenger compartment.Fourteen operating conditions consisting of three different ventilation parameters for top forced ventilation were numerically simulated.The simulation tests included the ventilation arrangements,air inlet angle and air inlet speed to verify their influence on cooling effects of monitoring points.Finally,the study optimized the combination of air delivery parameters based on the analysis of the air delivery parameters.The air inlet angle and air inlet speed were selected as the variables,the temperature values of key measurement point were the optimization objectives,and established corresponding functional relationships based on multi-objective genetic algorithm.The study calculated the objective value of the sample points based on the Latin hypercube method,and designed a functional equation and improved the fitted equations accuracy as to attain the optimal combination of parameters.The simulation results with optimized values had a contrast to the real value,the effectiveness of method is verified.The research results show that the ventilation area,air outlet arrangement,air inlet angle and air inlet speed have a greater influence on the cooling rate;The cooling rate and cooling effect in the passenger compartment are better when the return air outlet is symmetrically distributed on the left and right sides of the air inlet;The different thermal comfort requirements can be met by reasonably changing the air inlet angle;When the cooling rate and cooling effect are similar,the optimized inlet air speed is reduced by 0.9 m/s compared with that before optimization,which effectively reduces the energy consumption of the ventilation system and improves the efficiency of the forced ventilation system,providing an idea for the design of ventilation systems that take into account cooling efficiency and energy-saving type.