Contents
What is the difference between a nozzle flow and a throttle device?
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.
What happens in a throttling valve?
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. An example of a throttling process is an ideal gas flowing through a valve in mid position.
What happens to pressure in a throttling valve?
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. The head difference between the two curves’ operating points shown is the head (pressure) drop across the throttling valve.
What is the purpose 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.
Where is nozzle control governing is used?
Nozzle Control Governing Of Steam Turbine:- Nozzle control governing of steam turbine is basically used for part load condition. Some set of nozzles are grouped together (may be two, three or more groups) and each group of the nozzle is supplied steam controlled by valves.
What is nozzle governing?
In nozzle governing the flow rate of steam is regulated by opening and shutting of sets of nozzles rather than regulating its pressure. In this method groups of two, three or more nozzles form a set and each set is controlled by a separate valve.
Is throttling always Isenthalpic?
Since throttling process is isenthalpic, and for an ideal gas enthalpy is a function of temperature only, the temperature of an ideal gas does not change during a throttling process.
Which valve is best used for throttling?
butterfly valve
Among the most common valves, the butterfly valve is the most suitable for throttling. A full quarter turn can open or close the valve.
Does throttling increase pressure?
The pressure drop in a throttling device is caused by the increase in velocity. The velocity is increased due to the decrease in area of the device that the fluid is flowing into and then out of (e.g. throttling valve, porous plug, capillary tube).
Where is throttling process used?
An application of the throttling process occurs in vapor-compression refrigerators, where a throttling valve is used to reduce the pressure and reduce the temperature of the refrigerant from the pressure at the exit of the condenser to the lower pressure existing in the evaporator.
What is minimum governor speed?
Minimum speed: The Minimum speed is nothing but the speeds at the minimum radius of rotation of the balls without tending to move either way is called as minimum speed. 8. Governor effort: The mean force working on the sleeve for a given change of speed is termed as the governor effort. 9.