The reversible recuperative cycle

A reversible recuperative a/s cycle, with the maximum possible heat transfer from the exhaust gas, qj = Cp(74 — 7y), is illustrated in the T,s diagram of Fig. 3.2, where 7y = 72. This heat is transferred to the compressor delivery air, raising its temperature to 7x = 74, before entering the heater. The net specific work output is the same as that 

The internal thermal efficiency increases as 6 is increased, but unlike the CHT]r cycle efficiency, drops with increa.se in pre.ssure ratio r. This is because the heat transferred gj decreases as r is increased. 

Plots of thermal efficiency for the [CHTJr and [CHTXJr cycles against the isentropic temperature ratio x are shown in Fig. 3.3, for 6 = Ty/Tf = 4, 6.25. The efficiency of the [CHTJr cycle increases continuously with x independent of 6, but that of the [CHTXJr cycle increases with 6 for a given x. For a given 6 = Ty/T, the efficiency of the [CHTXJr cycle is equal to the Carnot efficiency at j = 1 and then decreases with x until it meets the 

The specific work of the two cycles is the same (Eq, (3.2)), and reaches a maximum at 

If reheat is introduced between a high pressure turbine and a low pressure turbine then examination of the T,s diagram (Fig. 3.4a) shows that the complete cycle is now made up 

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