WORK AND HEAT TRANSFER
ΔV=0, ΔP=0, ΔT=0, ΔU=0, Δh=0
Work done in various reversible processes
Process Work done
(i) Constant pressure (isobaric) w1-2 = p(v2 – v1) = mR (T2 – T1)
(ii) Constant volume (isochoric) w1–2 = 0
(iii) Constant Temperature (isothermal)
(iv) Adiabatic (isentropic)
n = polytropic const.
m = no. of moles
g = Adiabatic constant
Id — length of the p–v diagram along v–axis
ad — area of the p–v diagram
k — Spring constant
Brake power (BP) =
Mechanical efficiency
L — stroke of the piston
A — cross sectional area of the cylinder(πD2/4)
N — r.p.m of the crank shaft
n — number of cylinders
T — Torque on the crank shaft
Flow work : The flow work in an open system represents the energy transfered across the system boundary as a result of the energy imparted to the fluid by a pump, blower or compressor to make the fluid across the control volume. It is analogous to
displacement work. Flow work per unit mass Wflow = PV
P — pressure
v — specific volume
Specific heat c =
Heat capacity C = m.c
FQ = mlF
lF = Latent heat of fusion
• The latent heat of vaporisation is the amount of heat transferred to vaporize unit mass of liquid into vapour or condense unit mass of vapour into liquid at a constant pressure and temperature.
5 videos|103 docs|59 tests
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1. What is work transfer in the context of mechanical engineering? |
2. How does heat transfer differ from work transfer? |
3. What are the different types of heat transfer? |
4. How is work calculated in mechanical engineering? |
5. What are some examples of work and heat transfer in mechanical engineering? |
5 videos|103 docs|59 tests
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