# Chapter 1 : Fundamentals Concepts and Definitions of Thermodynamics¶

## Example 1.2 Page No : 16¶

In :
# Variables
Pvacc = 700.;			# mm of hg
Patm = 760.; 			# mm of hg

# Calculations
Pabs = Patm - Pvacc;			# mm of hg

# Results
print "Absolute pressure in in = %.4f kg/cm**2"%(Pabs/760)
print "Absolute pressure in = %.4f bar"%(Pabs*1.01325/760)
print "Absolute pressure in in = %.3f kPa"%(Pabs*1.01325/760*10**2)

Absolute pressure in in = 0.0789 kg/cm**2
Absolute pressure in = 0.0800 bar
Absolute pressure in in = 7.999 kPa


## Example 1.3 Page No : 16¶

In :
# Variables
Patm = 101;			# kpa
Rho = 13.6 * 10**3;			# in kg per m**3
h = 250;			# in cm
h = h*10**-2;			# in m
g = 9.806;

# Calculations
p = Rho * g * h;			# in N/m**2
p= p*10**-3;			# in kPa
# Total pressure in tank
p = p + Patm;			# in kpa
p = p*10**-3;			# in Mpa

# Results
print "Total pressure in tank in = %.3f Mpa"%p

Total pressure in tank in = 0.434 Mpa


## Example 1.4 Page No : 21¶

In :
import math

# Variables
m = 1.5;			    # in kg
pi = 0.1;			    # in MPa
pi= pi*10**6;			# in Pa
pf = 0.7;			    # in MPa
pf= pf*10**6;			# in Pa
rho_i = 1.16;			# kg per m**3

# Calculations and Results
vi = m/rho_i                    			# in m**3
WorkDone= pi*vi*math.log(pi/pf);			# in J
print "Work done in kJ is : %.2f"%(WorkDone*10**-3)

if WorkDone<0:
print ("The -ve sign indicates work is done on the system, hence");
print "The work done by the piston in kJ is : %.2f"%abs(WorkDone*10**-3)


Work done in kJ is : -251.63
The work done by the piston in kJ is : 251.63


## Example 1.5 Page No : 25¶

In :
# Variables
p = 1.0;    			# in Mpa
p = p*10**6;			# in N per m**2
del_v = 1.5;			#m**3 per min

# Calculations
del_v = del_v*60;			# m**3 per h
W = p * del_v;  			# W standard for work done in J
W = W*10**-6;	    		# in MJ

# Results
print "Work done by the pump upon the water in an hour in MJ is : ",W

Work done by the pump upon the water in an hour in MJ is :  90.0


## Example 1.6 Page No : 25¶

In :
# Variables
g = 9.81;
J = 4.1868*10**3;

# Calculations
# W = 2*g*h
# due to stirring of water

m = (0.2+10*10**-3)*10**3;			# in gm
s= 1;                   			# in cal per gm°C
del_T = 2;			                # in ° C
H = m * s * del_T       			# in cal
H = H*10**-3;			            # in kcal
# W = JH and W= 2*g*h
h = J*H/(2 * g);			        # in m

# Results
print "The height from the mass should be fall in meter is : %.2f"%h

The height from the mass should be fall in meter is : 89.63


## Example 1.7 Page No : 26¶

In :
# Variables
# mass of 1 litr of water is 1 kg. so
m = 5000;			# in kg
h = 10-1;			# in m
g= 9.81;			#

# Calculations
PE = m * g * h;			# in N m
PE = PE*10**-3;			# in kj
Eta = 0.85;
# Eta = energy output/energy input
E_input = PE/Eta;			# in Kj
E_input = E_input*10**3;			# in J
t = 45;			# time in min
t = t*60;			# in sec
P = E_input/t;			# in J/s
P = P*10**-3;			# in kW

# Results
print "Power required for the feed pump in kW is : %.3f"%P

Power required for the feed pump in kW is : 0.192


## Example 1.11 Page No : 29¶

In :
# Variables
V =  50.;			# km per hr
V = V * (1000./3600);			# in m per sec
F = 900.;			# in N

# Calculations and Results
P = F * V   			# in watt
P = P *10**-3;			# in kW
print "Power of the engine of a car in kW is : ",P

H = P * 60  			# in kJ
print "Heat equivalent of work per minute in kJ is",H

Power of the engine of a car in kW is :  12.5
Heat equivalent of work per minute in kJ is 750.0


## Example 1.12 Page No : 29¶

In :
# Variables
E_air = 200-100;			# in kJ/kg
E_lost = 40;    			# in kJ/kg

# Calculations
E_total = E_air + E_lost;			# in kJ per kg
M = 0.5;			# mass flow rate in kg per s
P = M * E_total;			# in kJ/s

# Results
print "Power required for an air mass flowin kJ/s is :",P

Power required for an air mass flowin kJ/s is : 70.0


## Example 1.13 Page No : 30¶

In :
# Variables
m_b = 1.;			# in kg
t_ib = 80;			#in degree c
m_w = 10.;			# in kg
t_iw = 25;			# in degree c
del_t = 5.;			# in degree c
S_w = 4.18;			#  in kJ/kg

# Calculations
t_equ = (t_iw + del_t);			# in degree c
# Heat loss by metal = Heat gained by water
S_b = m_w * S_w * (t_equ - t_iw)/(m_b * (t_ib - t_equ));			# in kJ/kg-K

# Results
print "Specific heat of metal block in kJ/kg-K is",S_b

Specific heat of metal block in kJ/kg-K is 4.18


## Example 1.15 Page No : 31¶

In :
# Variables
P_gauge = 90;			# in cm of hg
P_atm = 760;			# in mm of hg
P_atm = 76;			# in cm of hg

# Calculations and Results
P_abs = P_gauge + P_atm;			# in cm of hg
P_abs = P_abs * (101.32/76);			# in kPa
print "Reading of pressure in kPa is %.3f"%P_abs

# Part (b)
P_vacuum = 40;			# in cm of hg
P_abs = P_atm - P_vacuum;			# in cm of hg
P_abs = P_abs * (101.32/76);			# in kpa
print "Reading of pressure in Kpa %.2f "%P_abs

# Part (c)
Rho = 1000;			# in kg per m**3
g = 9.81;			#
h = 1.2;			# in m
P_gauge = Rho * g * h;			# in N m**2
P_gauge= P_gauge*10**-3;			# in kPa
P_atm = 101.32;			# in kPa
P_abs = P_gauge + P_atm;			# in kpa
print "Reading of pressure in kPa",P_abs

Reading of pressure in kPa is 221.304
Reading of pressure in Kpa 47.99
Reading of pressure in kPa 113.092


## Example 1.16 Page No : 32¶

In :
import math

g=9.81; 			# in m/s**2
P=1.0332*10**5;			# in kN/m**2

def f4(p):
return (1./p)**(1/1.4)


The value of H in km is : 12.61