Category: Advance Concept Mechanical Eng
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Isothermal Compression
In isothermal compression work done is minimum and it is maximum for adiabatic compression.
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Polytropic Compression
Area 0−1−2−3 in Figure 10.4 represents the net work done, when the compression follows the polytropic law. Net work on air per cycle = Area 0−1−2−3 = Work done during compression (1−2) + Work done during air delivery (2−3) − Work done during suction (0−1). Similarly, for isentropic compression
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RECIPROCATING COMPRESSORS
In these compressors, the gas volume decreases and pressure increases due to the action of one or more reciprocating piston moving axially in one or more cylinders. It may be single acting or double acting, single cylinder or multicylinder and single stage or multistage compressors. Figure 10.2 shows the schematic of a reciprocating compressor. Reciprocating compressors…
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CLASSIFICATION OF COMPRESSORS
Compressors can be classified on the basis of range of pressures, capacity, pressure ratio and design, and principle of operations. Figure 10.1 Classification of Compressors Positive Displacement Compressor: In this compressor, pressure is raised by decreasing the volume of gas, i.e., positive displacement of gas. Dynamic Compressor: In this compressor, the kinetic energy imparted to the gas by…
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INTRODUCTION
The function of compressor is to compress the gases and vapours from low pressure to high pressure. According to second law of thermodynamics this is only possible when work is done on the system, i.e., on the gas or vapour. Compressors have wide industrial and domestic applications such as compression of refrigerants in refrigerators and…
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HYDRAULIC TORQUE CONVERTER
In this case, torque on the driver and driven shafts are equal. The application is for direct drives of machines. But in some cases, the torque required at the driven shaft could be more than the torque on the driver shaft. In this case, speed will be in the reverse ratio. Such an application is…
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HYDRAULIC COUPLING
This device is used to transmit the power from one shaft to another. The driver shaft carries a pump with radial vanes and the driven shaft carries runners (Figure 9.30). Both of these are enclosed in a casing filled with oil of required viscosity. The pump accelerates the oil by imparting energy to it. The…
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Three-screw, High-pitch, Screw Pump
The three-screw, high-pitch, screw pump has many of the same elements as the two-screw, low-pitch, screw pump, and their operations are similar as shown in Figure 9.29. Three screws, oppositely threaded on each end, are employed. They rotate in a triple cylinder, the two outer bores of which overlap the centre bore. The pitch of the…
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Two-screw, Low-pitch, Screw Pump
The two-screw, low-pitch, screw pump consists of two screws of right-handed and left-handed threads mesh with close clearances, mounted on two parallel shafts. The driving shaft drives the other shaft through a set of herringbone timing gears. The gears maintain the clearances between the screws as they rotate and to promote quiet operation. The screws…