without inlet guide vanes and with a shroudlessbacksuept impeller, a vaned The complete design of a high-performance centrifugal compressor involves. Figure Flow lines for optimised compressor design (recirculation removed). Figure Pressure coefficient distribution over diffuser vane at varying spans . of the centripetal-flow fan at design operating conditions can reach % and , respectively, of the centripetal compressor from the point of view.
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Bernoulli’s fluid dynamic principle plays an important role in understanding diffuser performance. From the very start of the aero-thermodynamic design process,the aerodynamic considerations and optimizations [29,30] are critical to have a successful design. Propeller governor Propeller speed reduction unit. Full similitude is achieved when each of the 5 Pi-parameters are equivalent. System resistance or adverse pressure is proven mathematically to be the critical contributor to compressor surge.
The surge-line shown in Figure 5. The high back pressure, downstream of the impeller, pushes flow back over the tips of the rotor blades towards the impeller eye inlet. Hybrid versions of vaned diffusers include: The fourth parameter, specific speed, is very well known and useful in that it removes diameter.
The inlet to a centrifugal compressor is typically a simple pipe. For this reason it is only necessary to summarize that in the ideal case, the lowest specific fuel consumption would occur when the centrifugal compressors peak efficiency curve coincides with the gas turbine’s required operation line. Wikimedia Commons has media related to Centrifugal compressors. The Wikipedia entry for equations of state is very thorough.
Questions remaining would involve inlet or outlet which might involve leakage from the vsne or moisture condensation.
Most modern high efficiency impellers use “backsweep” in the blade shape. Generally, for vqne compressors, the velocity coefficient is of secondary importance while the Reynolds coefficient is of tertiary importance. Historically, centrifugal compressors applied to industrial applications were needed to achieve performance at a specific flow and pressure.
Compared to estimating performance which is very cost effective thus useful in designtesting, while costly, is still the most precise method.
Lines of constant power could just as easily be substituted.
An “End User” would be very happy with the performance requirements of 2. The first law of thermodynamics is the statement of the conservation of energy. Modern industrial compressors are often needed to achieve specific performance goals across a range of flows and pressures; thus taking a significant step toward the sophistication seen in compressof turbine applications.
The fifth parameter, specific diameter, is a less often discussed dimensionless parameter found useful by Balje. This of course would mean the two turbomachines being compared are geometrically similar and running at the same operating point. This is because it is nearly impossible to change one of these parameters independently.
In many cases the engineering methods used to design a centrifugal fan are the same as those to design a centrifugal compressor, so they can look very similar. This relationship is the reason advances in turbines and axial compressors often find their way into other turbomachinery including centrifugal compressors.
The next feature to be discussed is the oval shaped curves representing islands of constant efficiency. Centrifugal compressors are similar to axial compressors in that they are rotating airfoil-based compressors. Either the collector or the pipe may also contain valves and instrumentation to control the compressor.
For atmospheric air, the mass flow may be wet or dry including or excluding humidity. Centrifugal compressors are similar in many ways to other turbomachinery and are compared desihn contrasted as follows:. This creates a practical problem centripeta trying to experimentally determine the effect of any one parameter.