‫كتاب ميور المنهجي في علم الأمراض‬

Abstract

Heat exchangers are frequently used in industry especially in steam and gas turbines power plants, as air pre – heaters or economizers and the like. These are mainly used to recover part of the thermal energy in exhaust and flue gases. The measure of performance of these equipments is usually given as a heat recovered from the exhaust. Heat exchangers output depends on value heat ratio during hours of the operation. The high heat ratio is main, a good performance and useful work output. In this research the investigation concentrates on the thermal ratio and the number of transfer unit in heat exchangers in existing power stations. Three power stations in Sudan are examined: namely: 1. Khartoum North Thermal Power Station. 2. Garrey Power Station. 3. Kenana Sugar Factory. Temperatures and mass rate were measured and calculations were carried out and the results were presented, and discussed. For K.N.P.S heat ratio is calculated were examined using data obtained from unit one phase two in The results obtained revealed that: • The thermal ratio of the heat exchangers, in addition to their dependence on the thermal properties of the material from which they are made, was affected by the method of design and inlet conditions. The results of the tests showed that the shell and tube type of heat exchanger used I nKenana Sugar Factory, the thermal ratio was 0.73 it was about 0.749 for rotary heat exchanger used in Khartoum North Thermal Power Station, phase one unit two. • The greatest heat ratio are above 0.80 in block one phase one Garrey Power Station.