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The isentropic efficiency is . The variation of fluid density for compressible flows requires attention to density and other fluid property relationships. The fluid equation of state, often unimportant for incompressible flows, is vital in the analysis of compressible flows. Also, temperature variations for compressible flows are usually ...
Furthermore, stage efficiency is the product of blade efficiency and nozzle efficiency, or =. Nozzle efficiency is given by η N = V 2 2 2 ( h 1 − h 2 ) {\displaystyle \eta _{N}={\frac {{V_{2}}^{2}}{2\left(h_{1}-h_{2}\right)}}} , where the enthalpy (in J/Kg) of steam at the entrance of the nozzle is h 1 {\displaystyle h_{1}} and the enthalpy ...
Most steady-flow devices operate under adiabatic conditions, and the ideal process for these devices is the isentropic process. The parameter that describes how efficiently a device approximates a corresponding isentropic device is called isentropic or adiabatic efficiency. [12] Isentropic efficiency of turbines:
In the classical regime, expansions are smooth isentropic processes, while compressions occur through shock waves, which are discontinuities in the flow. If gas-dynamics is inverted, the opposite occurs, namely rarefaction shock waves are physically admissible and compressions occur through smooth isentropic processes. [24]
In practice, the flow of steam through a nozzle is not isentropic, but accompanied with losses which decrease the kinetic energy of steam coming out of the nozzle. The decrease in kinetic energy is due to: viscous forces between steam particles, heat loss from steam before entering the nozzle, deflection of flow in the nozzle,
Where 1 to 3ss in Figure 1 represents the isentropic process beginning from stator inlet at 1 to rotor outlet at 3. And 2 to 3s is the isentropic process from rotor inlet at 2 to rotor outlet at 3. The velocity triangle [ 2 ] (Figure 2.) for the flow process within the stage represents the change in fluid velocity as it flows first in the ...
A sub-plot shows the variation of isentropic (i.e. adiabatic) efficiency with flow, at constant speed. Some maps use polytropic efficiency. Alternatively, for illustrative purposes, efficiency contours are sometimes cross-plotted onto the main map. Note that the locus of peak efficiency exhibits a slight kink in its upward trend.
In a nozzle or other constriction, the discharge coefficient (also known as coefficient of discharge or efflux coefficient) is the ratio of the actual discharge to the ideal discharge, [1] i.e., the ratio of the mass flow rate at the discharge end of the nozzle to that of an ideal nozzle which expands an identical working fluid from the same initial conditions to the same exit pressures.