From b1f5c3f8d6671b4331cef1dcebdf63b7a43a3a2b Mon Sep 17 00:00:00 2001
From: priyanka
Date: Wed, 24 Jun 2015 15:03:17 +0530
Subject: initial commit / add all books

---
 2657/CH18/EX18.2/Ex18_2.sce | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100755 2657/CH18/EX18.2/Ex18_2.sce

(limited to '2657/CH18/EX18.2')

diff --git a/2657/CH18/EX18.2/Ex18_2.sce b/2657/CH18/EX18.2/Ex18_2.sce
new file mode 100755
index 000000000..102499e18
--- /dev/null
+++ b/2657/CH18/EX18.2/Ex18_2.sce
@@ -0,0 +1,39 @@
+//Calculations on Gas engine
+clc,clear
+//Given:
+d=24,l=48 //Bore and stroke in cm
+D_b=1.25 //Effective diameter of the brake wheel in m
+P=1236 //Net load on brake in N
+N=77 //Average engine explosions in min
+N1=226.7 //Average speed at output shaft in rpm
+imep=7.5 //Indicated mean effective pressure in bar
+Vg1=13 //Gas used in m^3/hr
+T1=15+273,P1=771 //Temperature and pressure of the gas in K and mm of mercury
+T2=0+273,P2=760 //Normal temperature and pressure (N.T.P.) in K and mm of mercury
+CV=22000 //Calorific value of the gas in kJ/m^3
+m_w=625 //Mass of cooling water used in kg/hr
+T1_w=25+273,T2_w=60+273 //Inlet and outlet temperature of cooling water in K
+//Solution:
+//(a)
+T=P*D_b/2 //Brake torque delivered in Nm
+bp=2*%pi*N1/60*T //Brake power in W
+ip=imep*10^5*l*%pi/4*d^2*N/60*10^-6 //Indicated power in W
+eta_m=bp/ip //Mechanical efficiency
+//(b)
+Vg2=(P1/P2)*(T2/T1)*Vg1 //Gas consumption at N.T.P. in m^3/hr
+//(c)
+eta_it=ip/1000*3600/(Vg1*CV) //Indicated thermal efficiency
+//Heat balance sheet
+Q1=Vg2/60*CV //Heat supplied in kJ/min
+Q_bp=bp/1000*60 //Heat equivalent to brake power in kJ/min
+cp=4.1868 //Specfic heat of water in kJ/kgK
+Q_w=m_w/60*cp*(T2_w-T1_w) //Heat in cooling water in kJ/min
+Q_r=Q1-Q_bp-Q_w //Heat to exhaust, radiation in kJ/min
+//Results:
+printf("\n (a)The mechanical efficiency of the engine, eta_m = %.1f percent",eta_m*100)
+printf("\n (b)The gas consumption at N.T.P. = %.1f m^3/hr",Vg2)
+printf("\n (c)The indicated thermal efficiency, eta_it = %.1f percent",eta_it*100)
+printf("\n\n   Heat balance sheet\n\t Heat supplied by the gas = %.1f kJ/min, %d percent",Q1,Q1/Q1*100)
+printf("\n\t Heat equivalent to b.p. = %.1f kJ/min, %.1f percent",Q_bp,Q_bp/Q1*100)
+printf("\n\t Heat in cooling water = %.1f kJ/min, %.1f percent",Q_w,Q_w/Q1*100)
+printf("\n\t Heat to exhaust, radiation = %.1f kJ/min, %.1f percent",Q_r,Q_r/Q1*100)
-- 
cgit