Table of Contents
Are all processes Polytropic?
1 Answer. No, all thermodynamic processes are not polytropic. That is, if the gas is ideal and the temperature is constant, the (polytropic) isothermal process is a good model.
Is a polytropic process reversible?
Polytropic processes are internally reversible. Some examples are vapors and perfect gases in many non-flow processes, such as: n=0, results in P=constant i.e. isobaric process.
How do you know if a process is Polytropic?
A polytropic process is one where the pressure and volume of a system are related by the equation PVn= C. Where P represents the pressure, V represents the volume, n represents the polytropic index, and C is a constant.
Which of the following is true for Polytropic process?
7. Which of the following is true for a polytropic process? Explanation: These are the properties of an adiabatic process. Explanation: It comes from the p1*(v1^n) = p2*(v2^n).
In which process work done is zero?
Is work done zero in isobaric process?
In an isobaric process, when the heat is transferred to the system some work is done. However, there is also a change in the internal energy of the system. This further means that no quantities as in the first law of thermodynamics become zero.
In which process work done is maximum?
The maximum work is done when the external pressure Pext of the surroundings on the system is equal to P, the pressure of the system. If V is the volume of the system, the work performed as the system moves from state 1 to 2 during an isobaric thermodynamic process, W12, is the maximum work as given by Eq.
Why is no work done in free expansion?
The gas expands on its own without external pressure acting on it. So according to the equation of work in thermodynamics W=Pext Δ V. Since external pressure is zero, the work done during the free expansion is zero.
What is work done in free expansion process?
In free expansion process as there is no work done as there is no external pressure so work done is 0.
Is free expansion reversible?
The Joule expansion (also called free expansion) is an irreversible process in thermodynamics in which a volume of gas is kept in one side of a thermally isolated container (via a small partition), with the other side of the container being evacuated.
What is a throttling process?
Throttling is a process where a high-pressure fluid is converted into low-pressure by using a throttle valve. In a throttling process, the enthalpy remains constant and the work done is zero.
Does throttling reduce pressure?
A throttling valve restricts the cross sectional area through which the fluid flows increasing supply or upstream pressure and reducing flow resulting in a decrease in pressure and flow on the unrestricted or down stream branch of the system.
Why Does entropy increase in throttling?
Therefore the condition becomes the effect of pressure on entropy at constant enthalpy. Because of the viscous heat generation in the throttling operation, the temperature change is small, and so the decrease in pressure (increase in volume) causes viscous dissipation within the fluid, which generates entropy.
What is the purpose of throttling?
A: Throttling valves are a type of valve that can be used to start, stop and regulate the flow of fluid through a rotodynamic pump. When the flow of a pump is regulated using a throttling valve, the system curve is changed. The operating point moves to the left on the Pump curve when the flow is decreased.
Is throttling isothermal?
Throttling is an isenthalpic process, as you have stated. For an ideal gas, it is also a constant temperature process, which means that the internal energy does NOT change. For an ideal gas, it is also a constant temperature process, which means that the internal energy does NOT change.
Are throttles Isenthalpic?
A throttling process is a thermodynamic process, in which the enthalpy of the gas or medium remains constant (h = const). In fact, the throttling process is one of isenthalpic processes.
Which if any of the following is an example of throttling process?
Throttling process is a thermodynamic process which is used to reduce or decrease the pressure of a fluid. In this process a liquid having high pressure is converted into low pressure fluid. Next the best example is the knob of deodorants, there the pressure is reduced by the method of flow through a small opening.
What is another name of adiabatic process?
Reversible adiabatic process is also called an Isentropic Process. It is an idealized thermodynamic process that is adiabatic and in which the work transfers of the system are frictionless; there is no transfer of heat or of matter and the process is reversible.
How much heat transfer occurs in adiabatic process?
In an adiabatic process, no transfer of heat takes place between system and surroundings.
Is throttling adiabatic?
A throttling process is defined as a process in which there is no change in enthalpy from state one to state two, h1 = h2; no work is done, W = 0; and the process is adiabatic, Q = 0. Finally, the theory states that an ideal throttling process is adiabatic.
What is the difference between nozzle flow and throttling process?
In both processes a flow moves from a higher to a lower pressure. In the nozzle the pressure drop generates kinetic energy whereas that does not take place in the throttle process. The pressure drop in the throttle is due to a flow restriction and represents a loss.
Is throttling reversible?
Throttling is a fundamentally irreversible process. The throttling due to the flow resistance in supply lines, heat exchangers, regenerators, and other components of (thermal) machines is a source of losses that limits the performance.
How does a throttling calorimeter work?
Principle: The principle of the throttling calorimeter is to throttle the wet steam so that it becomes superheated. The pressure gauge attached to the outer casing and thermometer in inner chamber gives the pressure and temperature of steam after throttling, respectively.
What is the difference between separating and throttling calorimeter?
Separating calorimeter does not give an accurate result and the throttling calorimeter fails if the steam is not superheated after throttling. A combination of separating and throttling calorimeter is therefore found most suitable for accurate measurement of dryness of steam.
What is dryness factor?
The steam dryness fraction is used to quantify the amount of water within steam. If steam contains 10% water by mass, it’s said to be 90% dry, or have a dryness fraction of 0.9. For example, saturated steam (100% dry) contains 100% of the latent heat available at that pressure.
What is a throttling calorimeter?
A throttling calorimeter isokinetically removes a steam sample out of the main steam pipeline and drops its pressure adiabatically, typically down to atmospheric pressure. The enthalpy, and main steam line pressure, is then used to calculate the quality of the steam in the main steam line.