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The simplest inlet to a centrifugal compressor is typically a simple pipe. Depending upon its use/application inlets can be very complex. They may include other components such as an inlet throttle valve, a shrouded port, an annular duct (see Figure 1.1), a bifurcated duct, stationary guide vanes/airfoils used to straight or swirl flow (see Figure 1.1), movable guide vanes (used to vary pre ...
A typical, single-stage, centrifugal compressor can increase the pressure by a factor of 4. A similar single stage axial compressors can only increase the pressure by a factor of 1.2 but axial compressors have an advantage over centrifugal compressors because of their ability to have multiple stages.
Compressor characteristic is a mathematical curve that shows the behaviour of a fluid going through a dynamic compressor.It shows changes in fluid pressure, temperature, entropy, flow rate etc.) with the compressor operating at different speeds.
For example, if the static compression ratio is 10:1, and the dynamic compression ratio is 7.5:1, a useful value for cylinder pressure would be 7.5 1.3 × atmospheric pressure, or 13.7 bar (relative to atmospheric pressure). The two corrections for dynamic compression ratio affect cylinder pressure in opposite directions, but not in equal strength.
The compressor pressure ratio is the ratio of the stagnation pressures at the front and rear of the compressor of a gas turbine. Overall pressure ratio in a high-bypass turbofan is a function of inlet pressure ratio and compressor pressure ratio: = The terms compression ratio and pressure ratio are used interchangeably. [1]
A low pressure ratio fan (such as that used on a high bypass ratio turbofan) has a range of working lines. At high flight speeds, the ram pressure ratio factors up the cold nozzle pressure ratio, causing the nozzle to choke. Above the choking condition, the working lines tend to coalesce into a unique steep straight line.
In turbomachinery, degree of reaction or reaction ratio (denoted R) is defined as the ratio of the change in static pressure in the rotating blades of a compressor or turbine, to the static pressure change in the compressor or turbine stage. Alternatively it is the ratio of static enthalpy change in the rotor to the static enthalpy change in ...
with T 1 and T 2 in degrees Rankine or kelvins, p 2 and p 1 being absolute pressures and = ratio of specific heats (approximately 1.4 for air). The rise in air and temperature ratio means compression does not follow a simple pressure to volume ratio.