Principle Components Of Rankine Cycle

Improved Essays
Principle components of Rankine cycle:

The four basic components of Rankine cycle are shown in figure 1 each component in the cycle is regarded as control volume, operating at steady state.
Pump: The liquid condensate leaving the condenser at the state 1 is pumped to the operating pressure of the boiler. The pump operation is considered isentropic.

Boiler: The heat is supplied in the working fluid (feed water) in the boiler and thus vapour is generated. The vapour leaving the boiler is wther saturated at the state 3 or superheated at the state 311, depending upon the amount of heat supplied in the boiler.

Steam power plant that operates on the Rankine cycle
Figure1: Simple steam power plant that operates on the Rankine cycle
Turbine: The
Rankine cycle
Figure 2: Rankine cycle
As mentioned earlier, the Rankine cycle also includes the possibility of superheating the vapor, as cycle 1–2–3–4–1.
If changes of kinetic and potential energy are neglected, heat transfer and work may be represented by various areas on the T–s diagram. The heat transferred to the working fluid is represented by area a–2–2–3–b–a and the heat transferred from the working fluid by area a–1–4–b–a. From the first law we conclude that the area representing the work is the difference between these two areas—area 1–2–2–3–4–1. The thermal efficiency is defined by the relation

For analyzing the Rankine cycle, it is helpful to think of efficiency as depending on the average temperature at which heat is supplied and the average temperature at which heat is rejected. Any changes that increase the average temperature at which heat is supplied or decrease the average temperature heat is rejected will increase the Rankine-cycle efficiency.

In analyzing the ideal cycles in this chapter, the changes in kinetic and potential energies from one point in the cycle to another are neglected. In general, this is a reasonable assumption for the actual
Why not select the Carnot cycle 1–2–3–4–1? At least two reasons can be given. The first reason concerns the pumping process. State 1 is a mixture of liquid and vapor. Great difficulties are encountered in building a pump that will handle the mixture of liquid and vapor at 1 and deliver saturated liquid at 2. It is much easier to condense the vapor completely and handle only liquid in the pump: The Rankine cycle is based on this fact. The second reason concerns superheating the vapor. In the Rankine cycle the vapor is superheated at constant pressure, process 3–3. In the Carnot cycle all the heat transfer is at constant temperature, and therefore the vapor is superheated in process 3–3. Note, however, that during this process the pressure is dropping, which means that the heat must be transferred to the vapor as it undergoes an expansion process in which work is done. This heat transfer is also very difficult to achieve in practice. Thus, the Rankine cycle is the ideal cycle that can be approximated in practice. In the following sections, we will consider some variations on the Rankine cycle that enable it to approach more closely the efficiency of the Carnot

Related Documents

• Improved Essays

On the other hand, fractional distillation separates two volatile liquids in order to achieve two purified components. In the case of this experiment, fractional distillation is used as the unknown liquids were thought to have similar boiling points. Fractional distillation utilizes a temperature gradient to ensure that the more volatile component…

• 1011 Words
• 5 Pages
Improved Essays
• Improved Essays

The instantaneous concentration of reactants and products are calculated from the burn fraction of fuel synthesized by the Wiebe function. The aim of the proposed model is to provide accurate thermodynamic conditions in the cylinder to facilitate the pressure and temperature calculations for performance prediction alone. The fluid mass flow rate and changes in fluid properties during intake and exhaust processes are calculated by a gas exchange process analysis [51] and detailed model is available in the earlier paper…

• 836 Words
• 4 Pages
Improved Essays
• Improved Essays

Fuel Cells

• 928 Words
• 4 Pages

Furthermore, in the straight pipe, a fully developed laminar assumption is satisfied under the condition that shape change is negligible. Numerical analysis technique the numerical analysis is performed by combining the governing equations related to the conservation of energy, conservation of mass and conservation of electrical charge to examine fluid distributions, heat transfers, mass transfers and electrochemical reactions. The assumptions used in developing the model are as follow: 1) Ideal gas law was employed for gaseous species. 2) The fluid flow in the fuel cell was laminar due to the low flow velocities and the small size of gas flow…

• 928 Words
• 4 Pages
Improved Essays
• Superior Essays

The hot and rapidly expanding gases are directed aft through the turbine rotor assembly. There thermal and kinetic energy are converted into mechanical energy. The gases are then directed out through the exhaust duct. Theoretical Cycle of GTE Let’s discuss a little on the cycle and theory of the gas turbine before we discussion on construction and design. As you are aware, a cycle is a process that begins with certain conditions.…

• 1872 Words
• 8 Pages
Superior Essays
• Improved Essays

Thermal dispersion mass flow meters, often called thermal mass flow meters, rely on the transmission of heat from a body to a gas flow. Inside the flow meter sensor head, a heated resistance thermometer (RTD) is electronically compared with an unheated RTD sensor. As a gas passes the heated RTD, heat is transferred from this sensor to the gas, and hence the RTD is cooled, thereby reducing the temperature difference between the two sensors. Heat transfer from the RTD to the process gas is based on the composition of the gas, therefore the temperature difference between the two RTDs is a function of the mass flow rate of the gas. The electronics of the meter can be an integral part of, the meter or mounted remotely (for instance for easy access…

• 1420 Words
• 6 Pages
Improved Essays
• Superior Essays

In turn, the blades of the turbine rotate and the Condenser transforms the steam to water which is pumped back into the boiler. The Carnot cycle is a theoretical cycle which operates at maximum efficiency with ideal conditions. Thus, the efficiency of the Rankine cycle (0.0134%) is evidently lower than the Carnot cycle…

• 3367 Words
• 14 Pages
Superior Essays
• Improved Essays

[10] 2.3 Operating Principles of distillation: The basic principle of distillation is to bring a liquid into close contact with vapour so that the mass transfer between the two current phases can take place. The goal of each system to reach a state of equilibrium is based on the driving force for the mass transfer. [11] When the vapour pressure matches the surrounding pressure that’s when a liquid begins to boil. The principle on which a liquid boils depends on its volatility. Liquids with high vapour pressures will boil at lower temperatures.…

• 898 Words
• 4 Pages
Improved Essays
• Improved Essays

• Flexi Coking: the unit crack the vacuum residues same as the Delayed coking, but it used steam to gasify most of the coke. The main characteristics of the thermal cracking and different between three processes are in Figure 3. These processes are part of the future refinery since they take care of heavy product from ADU/VDU, and they are relative simple, cracking through heat. Also, the main use of it in refinery thermal cracking is to prepare the feed to the catalytic cracking. In the future, they will become more efficient where most of the changes will be done in the heater internals and introduce a catalysts in the heater (Speight, 2011).…

• 1378 Words
• 6 Pages
Improved Essays
• Superior Essays

Besides, a bypass damper system, also called as an isolating damper system with seal air fans is necessary to ensure the hot gases do not leak to fan when the gas turbine is running. [2]. The formula below is used to express the leakage of gas across a damper by stating the assumptions, which most of dampers used for isolation of gas or air in ducts are nor 100% leak proof. They have a certain percentage of leakage which cause a flow of gas across the area. Considering the conditions to be similar to those of flow across an orifice, V_g= C_d √(2gH_w ρ_w/〖2ρ〗_g ) ………………………………..Equation 1 where; V_g is gas velocity through the leakage area in fps unit H_wis differential pressure across the damper in WC unit ρ_w and ρ_g is density of gas and water in lb/cu ft, g is acceleration due to gravity in ft/s2unit Cd coefficient of discharge which is 0.61 The gas flow W in lb/h can be obtained from W = 3600 ρ_g A (100 - E) (V_g/100)……………………………..…

• 920 Words
• 4 Pages
Superior Essays
• Improved Essays

Process 2-3 Constant- pressure heat rejection in a condenser. Process 3-4 Throttling in an expansion device. Process 4-1 Constant –pressure heat absorption in an evaporator. In the ideal vapour-compression refrigeration cycle, the refrigerant enters as a saturated vapor to the compressor at state 1 and is compressed isentropically to the condenser pressure at state 2. During this isentropic compression process the temperature of the refrigerant increases to the temperature which is well above that of the…

• 912 Words
• 4 Pages
Improved Essays