top of page
MECHNOZ
Engineer's World
Welcome to Mechnoz, a unique site here for you to explore Mechanical Engineering. We love having the opportunity to share our passions and thoughts with our loyal readers. Read on, and enjoy.
Home: Welcome
Search
Entropy change for various process
Entropy change for constant pressure process
We know that
dS = ʃ δQ/T
for P = C, Q = mCpdT
dS = mCp ʃ dT/T
dS = mCp ln (T₂/T₁)
(V₁/V₂) = (T
General gas Equation for entropy change
Consider a certain quantity of perfect gas being heated by any thermodynamic process.
Let m = mass of gas
P₁ = initial pressure of gas
V₁ =
Entropy
It is degree of randomness or disorganized form of energy is called entropy.
Equivalence of Kelvin Plank’s and Clausius statement
Although both the definitions of 2nd Law Thermodynamics seems to be different, one working for reversible heat engines and other working for
Relation between (COP)refrigerator and (COP)HP
Let us consider a reverse device which may work as refrigerator as well as heat pump if both the devices are taking and rejecting some amoun
Heat Pump
It is a device which is used to maintain the temperature of body higher than that of atmosphere while working in a cyclic process.
Refrigerator
It is a device which is used to maintain the temperature of body at a temperature lower than the atmospheric temperature while working in a
Second Law of Thermodynamics
It may be defined by two statements
1. Kelvin Plank’s statement
2. Clausius statement
Thermal Energy Reservoir
It is the body of infinite heat capacity which can absorbed or reject infinite amount of heat without any change in its thermodynamic proper
Limitations of First Law of Thermodynamics
this definition does not specify the direction in which the energy interaction takes place.
Throttling Process
Whenever a fluid flows through a constricted path like partially opened valves, there is decrease in pressure and the process is called
Steady Flow Energy Equation
The flow of fluid in which the properties of the fluid does not vary with time but can be varied w.r.t. space co-ordinates.
Free Expansion
The expansion of a gas against the vacuum is called free expansion.
Various close system processes
1. Constant Volume process ( isochoric process)
2. Constant Pressure process ( isobaric process )
3. Constant temperature process
Enthalpy
It is the sum of internal energy and product of pressure and volume. It is denoted by H.
Mathematically, H = U + PV
Corollaries (conclusion) of 1st Law of Thermodynamics
1. Internal energy is the property of the system.
2. Heat is a path function.
3. Internal energy of an isolated system remains constant.
Specific Heat, Specific Heat at constant Volume and specific Heat at constant Pressure
Specific Heat
It is the amount of heat required to raise the temperature of unit mass of substance through unit degree. It is denoted by C.
First Law of Thermodynamics
First Law of Thermodynamics can be stated as;
Heat and work are mutually convertible to each other during any change of state.
Zeroth Law of Thermodynamics
As per this law if a body A is in thermal equilibrium with body C and another body B is in thermal equilibrium with body C
Universal Gas Constant
Universal gas constant may be defined as the product of molecular weight and simple gas constant of a particular gas.
It is denoted by Ru
MECHNOZ
bottom of page