Why is the Rankine cycle modified?

The exhaust from the turbine is converted to liquid in the condenser and is pumped back to the boiler for heating up again. A modified Rankine cycle is used to increase the efficiency of the same Rankine cycle by either reheat or using regenerative cycle. This in turn increases the efficiency of the cycle.

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Just so, what is the use of Rankine Cycle?

The Rankine cycle is a model that is used to predict the performance of steam turbine systems. The Rankine cycle is an idealized thermodynamic cycle of a heat engine that converts heat into mechanical work. The heat is supplied externally to a closed loop, which usually uses water as the working fluid.

Similarly, is Rankine cycle reversible? In a real power-plant cycle (the name "Rankine" cycle is used only for the ideal cycle), the compression by the pump and the expansion in the turbine are not isentropic. In other words, these processes are non-reversible, and entropy is increased during the two processes.

what are the four process of Rankine Cycle?

The ideal Rankine cycle consists of the following four processes, as shown on the T-s diagram on the left: 1-2: Isentropic compression in a pump. 2-3: Constant pressure heat addition in a boiler. 3-4: Isentropic expansion in a turbine.

What are the advantages of reheat cycle?

The advantages of using a reheat cycle are higher thermal efficiency, reduced feed water pump power, smaller condenser, smaller boiler, long life of the turbine and less handling of the fuel and firing requirement.

Related Question Answers

How do you define enthalpy?

Enthalpy is a thermodynamic property of a system. It is the sum of the internal energy added to the product of the pressure and volume of the system. It reflects the capacity to do non-mechanical work and the capacity to release heat. Enthalpy is denoted as H; specific enthalpy denoted as h.

Where is Brayton cycle used?

In general, the Brayton cycle describes the workings of a constant-pressure heat engine. It is one of most common thermodynamic cycles that can be found in gas turbine power plants or in airplanes.

How can we increase the efficiency of Rankine Cycle?

There are three ways to increase the efficiency of the simple ideal Rankine cycle.

1. Decreasing the condenser pressure. The effect of lowering the condenser pressure on the Rankine cycle efficiency is illustrated on a T-s diagram on the left.
2. Superheating the steam to a high temperature.
3. Increasing the boiler pressure.

How many cycles are there in thermodynamics?

four

What is Rankine used for?

Rankine is commonly used in the aerospace industry in the United States. Rankine is to Fahrenheit what Kelvin is for Celsius. So when people in the United States were creating programs and using equations that needed an absolute temperature, they used Rankine before Celsius became dominate for scientific calculations.

What is the efficiency of Rankine Cycle?

Thermal Efficiency of Rankine Cycle: The thermal efficiency of the Rankine cycle is the ratio between the work produced by the steam turbine that has been reduced by the pump work, with the incoming heat energy from the boiler.

What is back work ratio?

Back Work Ratio : The fraction of the work produced by the turbine that is consumed by the compressor.

Is Carnot cycle reversible?

The Carnot cycle is reversible representing the upper limit on the efficiency of an engine cycle. Practical engine cycles are irreversible and thus have inherently lower efficiency than the Carnot efficiency when operating at the same temperatures.

What is the difference between Rankine cycle and Brayton cycle?

Difference : Brayton cycle consists of two reversible isobaric processes and Rankine cycle consist of two reversible adiabatic processes. Brayton cycle operates between a higher pressure ratio than the Rankine cycle for the same capacity.

What is the difference between Carnot cycle and Rankine Cycle?

Carnot cycle is an ideal cycle for heat engine which gives highest efficiency between given temperature difference but it is a theoretical cycle and actually no engine works on it. Rankine cycle is an ideal cycle of vapor or steam power generation. Carnot cycle has two isothermal processes and two isentropic processes.

Why Carnot cycle is not possible?

Carnot cycles are not encountered in reality since achieving isothermal heat transfer is very difficult (needs very large heat exchangers and long time). Also process 3-4 requires a pump or compressor that can handle two phase mixture (liquid and vapor) which is impractical.

Why pump is used in Rankine Cycle?

Originally Answered: Why is a condenser used in a Rankin cycle? A condenser is used to convert the steam from the exit of the turbine to saturated liquid. This is done so that we can use a pump to pressurize the liquid. There is no mechanical device till date which can work on steam+liquid mixture.

Who invented Rankine?

William John Macquorn Rankine

What is the law of entropy tell us?

Entropy is one of the consequences of the second law of thermodynamics. The most popular concept related to entropy is the idea of disorder. Entropy is the measure of disorder: the higher the disorder, the higher the entropy of the system. This means that the entropy of the universe is constantly increasing.

What is a Rankine cycle process?

Rankine cycle. The Rankine cycle or Rankine Vapor Cycle is the process widely used by power plants such as coal-fired power plants or nuclear reactors. In this mechanism, a fuel is used to produce heat within a boiler, converting water into steam which then expands through a turbine producing useful work.

What is reverse Rankine Cycle?

An ideal thermodynamic cycle consisting of heat addition at constant pressure, isentropic expansion, heat rejection at constant pressure, and isentropic compression; used as an ideal standard for the performance of heat-engine and heat-pump installations operating with a condensable vapor as the working fluid, such as

What is Carnot efficiency?

The Carnot Efficiency is the theoretical maximum efficiency one can get when the heat engine is operating between two temperatures: The temperature at which the high temperature reservoir operates ( T_Hot ).

How do you increase the efficiency of a condenser?

Reducing cooling water temperatures is a sure-fire way to improve condenser performance: A decrease in cooling water temperature of 10 degrees F can improve the overall heat rate of a power plant by 1%.

What is work ratio in Rankine Cycle?

Practical Rankine cycle Pump and Turbine do not operate isentropically in practice. The practical Rankine cycle is shown as 1-2 -3-4 -1. Isentropic efficiency of turbine (h_T) is defined as the ratio of Work delivered by actual turbine to Work delivered by an isentropic turbine .