5/30/2023 0 Comments Workdone rankine cycle by ethalpyThe Carnot cycle is the model of an ideal refrigeration cycle whereas, the Rankine cycle is the standard vapor power cycle. Power generation using steam involves the pressurization of steam using heat (Qa) followed by expansion in a turbine to produce power (Ws). Refrigeration implies the production of lower temperature by continually absorbing heat at a lower level and rejecting it at a higher level. For steam power generation rankine is the ideal cycle. In the refrigeration process, the temperature below than the surrounding is maintained Whereas Steam power generation involves the use of pressurized steam to drive turbines. Refrigeration is an essential process in the liquefaction of life-saving gases such as oxygen. Steam power is utilized in thermal power plants to produce electricity that powers our homes. This causes less fuel to be used because excess heat normally lost to the environment preheats the fluid.Steam power generation and refrigeration are some of the most important processes in Industries. This raises the average temperature across the cycle by using fractional steam to make the initial water hotter. Regeneration in the Rankine cycle is the process of mixing liquids at different stages of the cycle to induce direct contact heating. A reheat Rankine cycle also improves the efficiency of the cycle all around because it adds more ability to capture the remaining energy leftover from the first turbine. This process stops the vapor from condensing inside the turbine and prevents damage to the blades. The steam runs back through the boiler, reheats, and then goes through a second turbine. Reheating in the Rankine cycle happens after the first turbine. The mass transfer rate( ṁ) helps determine this information. There are different equations that show the transfer of heat to and from the system and the work performed by various components. Other Calculations of the Rankine Cycle Ideal Lastly finding the work across the turbine as the stage 1 values of the Rankine cycle have been previously found.įinally, take the efficiency of the turbine ( ηt) to determine actual turbine work. The pressure at stage 4 is equal to that of stage one( P4 = P1). Then using the quality to find the enthalpy ( h4). Use the entropy to find the quality of the vapor after the turbine. Since its isentropic, the entropy( s4) is equal to ( s3). Next, use the found quality to find the enthalpy( h4). Use this relationship to find the quality of the vapor at stage four. Given the temperature going into the turbine( T3) or the pressure into the turbine( P3), and then using those with the steam tables to find the enthalpy at state 4. This is done via steam tables and taking the quality of the steam to be (x3 = 1), which is a superheated vapor. Use the pressure and temperature to find the enthalpy ( h3) and entropy ( s3) at stage three of the cycle from the pressure and temperature. The pressure at stage 3 equals the pressure at stage 2 ( P3 = P2) and the given temperature after the boiler( T3). Next, the pump work determines the enthalpy( h2). These variables determine the actual work of the pump. Next the enthalpy( h1), entropy( s1), and specific volume( νf) are still equal to ( hf, sf, νf) at the given pressure( P1). In the actual cycle, the variable of pump efficiency( ηp) influences the amount of work placed into the cycle. Finally, the vapor is put into a condenser and made back into liquid water in an isobaric process. The steam then runs through a turbine and undergoes an isentropic expansion. After the water is turned into steam and sent to the next stage. Next, the water is heated in a boiler, traditionally via fossil fuel combustion and an isobaric process. The process starts with the pump bringing in water into the system and increasing pressure via an Isentropic compression process. The Rankine cycle consists of four main components: pump, boiler, turbine, and condenser. In this article, you will learn the principles of the Rankine cycle, calculation of values, and variations of the cycle. It can also have reheat or even regenerative components to increase efficiency. This contrasts with most thermodynamic cycles that use air or some sort of fuel. The Rankine cycle is a thermodynamic cycle that allows uses steam as the working fluid inside of a cycle.
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