The simulation on an evaporator of an R134a air-conditioning unit was conducted with a steady state distribution parameter model.Using the update Kattan model

R134a flow patterns inside smooth tubes were divided

and then the flow pattern map was obtained.Based on the flow pattern map

local boiling heat transfer coefficients were calculated with different correlations.The surface heat transfer coefficient and the pressure drop of louver fin evaporators were calculated with C C Wang's model.The moisture separation coefficient was determined from the database established with test data.During simulation

implicit cubic polynomial curve-fitting model was used to calculate R134a thermodynamic properties.The results show that the simulation values are in agreement with the experiment data.The average relative error of refrigeration capacity

dry bulb temperature of outlet air

and R134a outlet temperature is 1.12%

1.25%

and 4.0%

respectively.Moreover

the maximum relative error of outlet-air enthalpy is 0.88%.