having trouble with calculating the efficiency of internal heat ex changer. The results which i got are far from the actual testing results. is there any way i can do my simulations which could be almost the same as actual results. the current boundary conditions which i am using are inlets with  flow rate of 0.02833 kg/s T= 15 deg/cent and outlet with 350 Kpa ( static pressure) on low pressure side and  and  0.02833 kg/s T= 50deg/cent and outlet with 1600 Kpa ( static pressure) on high pressure side. ​