The suction state of a compressor is among the most important indicators of its safety and efficiency

but the suction state cannot be measured accurately

particularly for a system with a large refrigerating capacity and high refrigerant flow rate. Based on a certain number of measured parameters

such as temperature

pressure

and other parameters

asuctionstate prediction model is established to determine whether the suction state is in the superheated or two-phase region and calculate the superheating degree and vapor quality of suction

respectively. The results show that the compressor exhaust

condensation

and evaporation temperatures have a linear effect on the vapor quality of suction. The model works in a wide range

with the evaporation temperature﹣35–12 ℃

the condensation temperature 35–68 ℃

and the minimum vapor quality 0.76.