//Chapter-5, Illustration 16, Page 265 //Title: Air Compressors //============================================================================= clc clear //INPUT DATA N=220;//Speed of compressor in rpm P1=1;//Pressure entering LP cylinder in bar T1=300;//Temperature at point 1 in K Dlp=0.36;//Bore of LP cylinder in m Llp=0.4;//Stroke of LP cylinder in m Lhp=0.4;//Stoke of HP cylinder in m C=0.04;//Ratio of clearance volumes of both cylinders P2=4;//Pressure leaving LP cylinder in bar P5=3.8;//Pressure entering HP cylinder in bar T3=300;//Temperature entering HP cylinder in K P6=15.2;//Dicharge pressure in bar n=1.3;//Adiabatic gas constant Cp=1.0035;//Specific heat at constant pressure in kJ/kg-K R=0.287;//Universal gas constant in kJ/kg-K T5=T1;//Temperature at point 5 in K //CALCULATIONS x=(n-1)/n;//Ratio Vslp=(3.147*(Dlp^2)*Llp*N*2)/4;//Swept volume of LP cylinder in m^3/min nv=1+C-(C*((P2/P1)^(1/n)));//Volumetric efficiency V1=nv*Vslp;//Volume of air drawn at point 1 in (m^3)/min m=(P1*100*V1)/(R*T1);//Mass of air in kg/min T2=T1*((P2/P1)^x);//Temperature at point 2 in K QR=m*Cp*(T2-T5);//Heat rejected in kJ/min V5=(m*R*T5)/(P5*100);//Volume of air drawn in HP cylinder M^3/min Plp=P2/P1;//Pressure ratio of LP cylinder Php=P6/P5;//Pressure ratio of HP cylinder Vshp=V5/nv;//Swept volume of HP cylinder in m^3/min Dhp=sqrt((Vshp*4)/(3.147*Lhp*N*2));//Bore of HP cylinder in m P=(m*R*(T2-T1))/(x*60);//Power required for HP cylinder in kW //OUTPUT mprintf('Heat rejected in intercooler is %3.1f kJ/min \n Diameter of HP cylinder is %3.4f m \n Power required for HP cylinder is %3.0f kW',QR,Dhp,P) //==============================END OF PROGRAM=================================