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In fluid dynamics, an isentropic flow is a fluid flow that is both adiabatic and reversible. That is, no heat is added to the flow, and no energy transformations occur due to friction or dissipative effects. For an isentropic flow of a perfect gas, several relations can be derived to define the pressure, density and temperature along a streamline.
The isentropic stagnation state is the state a flowing fluid would attain if it underwent a reversible adiabatic deceleration to zero velocity. There are both actual and the isentropic stagnation states for a typical gas or vapor. Sometimes it is advantageous to make a distinction between the actual and the isentropic stagnation states.
The affinity laws are useful as they allow the prediction of the head discharge characteristic of a pump or fan from a known characteristic measured at a different speed or impeller diameter. The only requirement is that the two pumps or fans are dynamically similar, that is, the ratios of the fluid forced are the same.
A fan may have two maps, one for the bypass (i.e. outer) section and one for the inner section which typically has longer, flatter, speed lines. Military turbofans tend to have a much higher design fan pressure ratio than civil engines. Consequently, the final (mixed) nozzle is choked at all flight speeds, over most of the throttle range.
An axial fan is a type of fan that causes gas to flow through it in an axial direction, parallel to the shaft about which the blades rotate. The flow is axial at entry and exit. The fan is designed to produce a pressure difference, and hence force, to cause a flow through the fan. Factors which determine the performance of the fan include the ...
Sound speed is defined as the wavespeed of an isentropic transformation: (,) (), by the definition of the isoentropic compressibility: (,) (), the soundspeed results always the square root of ratio between the isentropic compressibility and the density: .
In fluid dynamics, the pressure coefficient is a dimensionless number which describes the relative pressures throughout a flow field.The pressure coefficient is used in aerodynamics and hydrodynamics.
Y th : theoretical specific supply; H t : theoretical head pressure; g: gravitational acceleration For the case of a Pelton turbine the static component of the head is zero, hence the equation reduces to: = ().