Joule-Brayton cycle

Temperature - entropy diagram Fig. 1.4. Joule-Brayton cycle (after Ref. [1]). 

The reversible simple (Joule-Brayton) cycle, [CHTJn... 

The Joule-Brayton (JB) constant pressure closed cycle is the basis of the cyclic gas turbine power plant, with steady flow of air (or gas) through a compressor, heater, turbine, cooler within a closed circuit (Fig. 1.4). The turbine drives the compressor and a generator delivering the electrical power, heat is supplied at a constant pressure and is also rejected at constant pressure. The temperature-entropy diagram for this cycle is also... 

For an irreversible gas turbine cycle (the irreversible Joule-Brayton (UB) cycle of Fig. 1.9), less than unity) and < 1 so that the thermal efficiency is... 

We next consider the application of the exergy flux equation to a closed cycle plant based on the Joule-Brayton (JB) cycle (see Fig. 1.4), but with irreversible compression and expansion processes—an irreversible Joule-Brayton (IJB) cycle. The T,.s diagram is as shown in Fig. 2.6. 

This cycle also uses continuous counterflow heat exchanger and is closely related to the Joule-Thomson and Claude cycles as shown in Fig. 5.15(a) [60], The cryocooling or reverse Brayton cycle derives from a reciprocating gas engine patented by G. B. Brayton in... 

The ideal Brayton gas turbine cycle (sometimes called Joule cycle) is named after an American engineer, George Brayton, who proposed the cycle in the 1870s. The gas turbine cycle consists of four processes an isentropic compression process 1-2, a constant-pressure combustion process 2-3, an isentropic expansion process 3-4, and a constant-pressure cooling process 4-1. The p-v and T-s diagrams for an ideal Brayton cycle are illustrated in Fig. 4.1. 

If, in the heat pumps, the energy of compression is not recovered but is wasted in letdown valves (as the pressure of the working fluid is reduced to the low pressure of the evaporator (Joule-Thomson cycle), the liquefaction efficiency will be low (35-60%). This range of efficiencies is a function of the liquefier size and refrigerant used. If the letdown valves are replaced by turbo expanders (Brayton cycle), which recover some of the compression energy during pressure letdown, and if helium or neon refrigerants are used, the efficiency can theoretically reach 80-90%. 

Refrigeration down to 80°K is therefore provided by LN2. The next step of refrigeration from 80 to 30°K is carried out using the Brayton cycle, in which high-pressure H2 is expanded in a number of turbo expanders in series. From 30°K to liquefaction, the Joule-Thomson cycle is used, where high-pressure gas is throttled to low pressure to provide further cooling. 

The Claude cycle is shown in Figure 6. This is a compound cycle which is actually a combination of the simple Joule-Thompson cycle and Brayton cycle. Most modern air separation plants utilize a variation of the Claude cycle to provide the refrigeration needed to liquefy air for distillation. 

BRAYTON CYCLE (also referred to as the Joule Cycle) - A rotating machine in which compression and expansion take place. Gas turbine are such an example. 

Brayton Cycle. The Brayton, or Joule, cycle consists of isentropic compression, constant pressure heat addition, isentropic expansion, and constant-pressure heat rejection. 

Fig. 5.15. Schematic diagram of Joule-Thomson (a) and Brayton (b) cooling cycles [60].

Brayton (or Joule) Cycle Efficiency, itip. Percent ... 

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