Application Fundamental Study On Aircraft Ground Air Conditioning Unit

At present,civil airliners use the aircraft ground air conditioning unit(PCA unit)instead of the aircraft's own environmental control system to provide a comfortable environment for the cabin.China's research on aircraft ground-mounted air-conditioning units started relatively late.At this stage,both national standards and manufacturers are mainly referring to and applying foreign selection models,which has also created a gap in the domestic technology area.Based on the current design of aircraft ground air conditioning air outlet air temperature,the key parameters such as the source is not clear and there is a big optimization space premise,this article embarks from the PCA unit service aircraft,by studying the load characteristics of the aircraft,cabin air distribution,etc.,combining with the characteristics of PCA optimal operation of the unit itself and get the key parameters affecting the aircraft ground air conditioning unit design,to provide PCA manufacturers design reference in the future.For aircraft manufacturers to provide aircraft ground when stop environmental parameters,by using a wide range of main parameters of a Boeing 737 as the basis,further study of structure of heat transfer and radiation heat transfer characteristics differ from conventional load calculation of the additional load,which was carried out on the aircraft cockpit wall block division,and then divided into cell structure respectively,using the numerical calculation for aircraft heat load,considering the temperature rise of the supply air fan and air duct load at the same time,determine the PCA unit actual demand.Based on this,in the range of-3?M4?at the outlet air temperature of the aircraft's ground-mounted air-conditioning unit,four air supply conditions that are different from the foreign aircraft manuals and domestic aviation industry standards under the same environmental parameters are calculated.There is an inverse relationship between the supply air temperature and air supply volume entering the cabin.Modeling,meshing and setting of boundary types in Gambit's software,and then using CFD(RNG k-? model)to simulate the combined effects of forced ventilation and body heat dissipation in the passenger cabin,six cabins The distribution of the velocity and temperature fields of the flowing air.Comparing the satisfaction of human comfort in the six operating conditions,the domestic air supply will make people feel a clear sense of air flow,under the air supply conditions where both the current temperature and the air supply volume of the two working conditions are relatively small.Can fully meet the requirements of the personnel comfort environment,the foreign operating conditions and the domestic standard operating conditions are greater than the actual use of demand.The results show that the parameters and the domestic line standard of foreign aircraft manual performance coefficient are less than ideal air supply parameters proposed in this paper,supply air temperature of 4?,send air volume is 43663m3/h),PC A unit with the parameters of air supply,satisfy the cabin comfort requirements.Compared with domestic line of the air supply parameters,supply air temperature increased 2?,air output fell by almost 25%;Compared with foreign aircraft manual air supply parameters,supply air temperature increased the 42?,air output fell by almost 3%,obvious energy saving.At the same time,the new three-stage compressor refrigeration system is superior to the commonly used two-stage compressor refrigeration system in terms of performance coefficient and refrigerating capacity.The research results can provide some references for the design,development and structural optimization of aircraft ground air conditioning in China.