大型拖拉机驾驶室热舒适性评价

With the dramatically growing use of agricultural high-power tractors, comfort of cab is an important problem in China. Because of the indirect impact with low comfort of the cab, the productivity is restricted. Health of tractor drivers was also undermined by low comfort of the cab. According to the least energy principle, the factors of comfort cab were defined. One of them was the thermal comfort. The simulation and dynamic assessment of comfort tractor cab were studied. The results showed that during the whole period of cooling process, the wind speed was 0.2 m/s which was accorded with the comfort demands and the minimum of temperature in the cab was 18℃. Firstly, the governing equations that contained CFD and thermal comfort assessment equations were deduced. The equation temperature and the monitor temperature were less different so that comfort zone theory could be used in cab thermal comfort design. In order to get the best value of parameters, the orthogonal simulation test was used. The speed and temperature of wind were significant to the cooling effects and the angel was not significant to the cooling effects according to the simulation results. The temperature of head zone began to decline at 41 s initially and went into the comfort zone firstly. At 10 min during the cooling period, each limb of tractor driver felt comfort and the most comfortable was at 21 min. This cooling result could be set default value in intelligent control system. After 50 min, the temperature of tractor cab would be into the uncomfortable cold zone if cooling was continued. Then the dynamic comfort process was calculated by predicted mean vote and predicted percentage dissatisfied. Because the predicted mean vote was declined rapidly, the feeling of drivers became better rapidly. Predicted percentage dissatisfied declined firstly and ascended after 50 min. It was showed that the comfort feeling was in a time segment if cooling was continued. The assessment results also confirmed the correctness of the simulation results. The simulation results also provided certain reference basis for intelligent temperature control and air cleaning design of high-power tractor cab.