Defrosting And Demisting Analysis Of Automobile Front Windshield

With automobile developed into intelligent era, study of vehicle active safety in order to improve driving safety has always been a timeless research. The frost outside the surface of vehicle windshield and the mist inside the surface of the vehicle windshield will reduce visibility to the driver, affecting the driver’s field of vision. Severe cases can even lead to a major accident. So defrosting and demisting, has a very important practical significance.Firstly, five parameters on defrosting were selected, namely intake air temperature and air flow rate, plane angle, impact angle and number of openings. They are very important factors affecting defrosting. In each factor, two or three specific parameters was chosen to study. Temperature and liquid fraction contours of different parameters contrasted at the same time and temperature and liquid fraction contours of same parameters contrasted at different time, and in additional average liquid fraction of the three selected points changing with time in the text contrasted, the conclusion is:the plane angle of 15 degrees,60 degrees of collision angle and two inlets are most favorable factors of defrosting,, which are all cleaning the fros within time. In case of the inlet temperature and velocity, although the higher inlet gas temperature and velocity, the faster defrosting, but the higher the inlet gas temperature and velocity, the more energy is consumed, and the more discomfort of the body, so 288K stream temperature and 15m / s air velocity was chosen for defrostingNext, three factors were chosen for demisting, respectively intake airflow temperature, intake air flow relative humidity, as well as the intake airflow rate. Cold air-flow parameter for demisting is advantageous because the air temperature inside and outside the car will reach a similarity within a short period of time, thus preventing condensation of water vapor, and also accelerating the fog volatilizing on the glass. The lower the relative humidity, the faster the demisting, because with the other parameters constant, lowering the relative humidity of the air can reduce the water vapor concentration in the body air layer, so that the mass concentration near the surface of the glass becomes large difference, thus speeding up the rate of droplet evaporation.So choosing 25% relative humidity as demisting parameter. As for the gas flow rate, the faster the flow, the faster the evaporation of the droplet, so 300m3/h was chosen for demisting.Finally, the paper also studies the impact of simulation on intake air temperature on the driver’s. Because the temperature is relatively low, while demisting, cold air blowing in the summer, hot air blowing in the winter.