Theory Of Compressors Performace

Theory of Compressors Performace

by

josephperez7080

The thermodynamic cycle for a compressor is represented on the pressure-volume is a suction phase at constant supply pressure (Ps); 2-3 is a compression phase following the gas law pvn= C, 3-4 is a discharge phase at constant delivery pressure (Pd). The area of this cycle diagram represents the theoretical work required to drive the compressor.

When the process of compression is carried out at a constant temperature, it is knows as isothermal and the air follows the law pv = C. and when the air is compressed rapidly or in a perfectly insulated cylinder. Without any heat losses, the process is known as adiabatic and air follows the law pvk = C, where k = 1.406 for air.

In practice n is between 1 and k. The higher the value of n, the steeper the compression curves and the greater is the power requirement. Thus if isothermal compression is attained, there would be substantial power savings, as shown by the cross-hatched area.

Multi-stage Compression: To meet the requirement of pneumatic construction equipments, air compressors employ multistage compression; with inter cooling between the stages. This multistage compression with inter cooling result in,

(I) a saving in power; and (II) improved volumetric efficiency. Perfect cooling for two stage compression requires that the air be cooled back to the original temperature. Point 5\’ is located in the isothermal compression line 2-3\’. The power saving, over single stage adiabatic compression is shown by the cross-hatched area. The figure also indicates that the extent of saving of power is determined by the degree of inter cooling and also by the pressure at which the inter cooling effected.

TYPES OF AIR COMPRESSORS

As explained above air-compressors are of positive displacement type and non positive displacement type of compressor. Positive displacement compressors are mainly Reciprocating Air Compressors, Rotary Air Compressor and Screw Air Compressors. Whereas non-positive displacement type of compressors are centrifugal compressors and Axial-flow compressors.

The positive displacement compressors deliver air at high pressure, where as non-positive displacement compressors give large volume of air at low pressure and are used in various industrials as blowers. Since construction Equipments require air at high pressure (generally at or above 7 kg/cm2), positive displacement compressors are used for their operation. In this chapter we shall confine ourselves to positive displacement compressors only.

Looking for leading manufacturers and exporters of Thermowell from India we manufacturer Thermowells, Flanged Thermowell, Socket Thermowells, Sanitary Wells, Van Stone Wells, Weld in Wells in Stainless Steel 304, 316, 304L, 316L, 310, 321 and 446?

Looking for leading manufacturers and exporters of

Thermowells

from India we manufacturer

Thermowell

, Flanged Thermowell, Socket Thermowells, Sanitary Wells, Van Stone Wells, Weld in Wells in Stainless Steel 304, 316, 304L, 316L, 310, 321 and 446?

Article Source:

ArticleRich.com