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Internal Combustion Engines
Published in Iqbal Husain, Electric and Hybrid Vehicles, 2021
The heat engines of interest for the hybrid vehicle applications, primarily the IC engine and the gas turbine, will be discussed in this section. An IC engine is a heat engine that utilizes gas as a working fluid. The IC engines use heat cycles that gain their energy from combustion of fuel within the engine. The IC engines can be reciprocating type, where the reciprocating motion of a piston is converted to linear motion through a crank mechanism. The IC engines used in automobiles, trucks and buses are of the reciprocating type where the processes occur within reciprocating piston-cylinder arrangement. The gas turbines used in power plants are also IC engines where the processes occur in an interconnected series of different components. The Brayton cycle gas-turbine engine has been adapted to automotive propulsion engine and has the advantage of burning fuel that requires little refining and the fuel burns completely. The gas turbines have fewer moving parts since there is no need to convert the rotary motion of the turbine. The disadvantages of gas turbines for automotive applications are complex construction, high noise levels and relatively lower efficiency for smaller-sized engines. Nevertheless, gas turbines have been considered for hybrid electric vehicles and prototype vehicles have been developed.
Availability Analyses of Engineering Cycles
Published in W. Li Kam, Applied Thermodynamics: Availability Method And Energy Conversion, 2018
The set of these assumptions is called the air-standard cycle approach. The idealized gas turbine cycle is referred to as the Brayton cycle. Figure 7-5 shows the Brayton cycle and its T-s diagram. To evaluate the first law cycle efficiency, we determine the cycle net work, which is also the net heat supply to the cycle. That is, wcy=cp(T3−T2)−cp(T4−T1)=cpT1(T3T1−T2T1−T4T1+1)
Radial Gas Turbines
Published in V. Dakshina Murty, Turbomachinery, 2018
By making a simplifying assumption that the turbine and compressor efficiencies are equal, a plot of temperature ratio versus pressure ratio can be made, as shown in the next figure. It can be seen that for a pressure ratio of eight, the ratio of maximum to minimum temperatures (T3/T1) should be about three with compressor and turbine efficiencies around 80%. Thus, if the inlet temperature is around room temperature (300 K), the turbine inlet temperature must be about 900 K just to break even in terms of the turbine and compressor work. Usually, the temperatures need to be much higher to provide any net work output from the cycle. The absence of materials capable of withstanding such high temperatures has been the main drawback of the Brayton cycle in power production.
A detailed study of IC engines and a novel discussion with comprehensive view of alternative fuels used in petrol and diesel engines
Published in International Journal of Ambient Energy, 2021
I. Vinoth Kanna, M. Arulprakasajothi, Sherin Eliyas
In 1872, George Brayton (1830–1892), an American mechanical engineer, patented and commercialised a constant pressure internal combustion engine, ‘Brayton’s Ready Engine’. The engine used two reciprocating piston-driven cylinders, a compression cylinder, and an expansion cylinder. This cycle was also called the ‘flame cycle’, as the ignition of the gas–air mixture was by a pilot flame, and the mixture was ignited and burned at constant pressure as it was pumped from the compression cylinder to the expansion cylinder. The Brayton piston engine was used on the first automobile in 1878. The Brayton cycle is the thermodynamic cycle now used by gas turbines, which use rotating fan blades to compress and expand the gas flowing through the turbine (Black 1991; Vinoth Kanna 2018a; Vinoth Kanna, Vasudevan, and Subramani 2018c; Subramani and Vinoth kanna 2018).
Off-Design Analysis of a Supercritical CO2 Brayton Cycle with Ambient Air as the Cold Source Driven by Waste Heat from Gas Turbine
Published in Heat Transfer Engineering, 2021
Jianming Han, Qingya Ma, Zihua Wang, Mengjuan Xu, Yunfei Song, Jiangfeng Wang, Yiping Dai
Khan and Tlili [6] researched gas and steam bottoming cycles thermodynamically driven by the exhaust gas from gas turbine. Results indicate that the steam bottoming cycle has better performance for higher values of gas turbine inlet temperature. Supercritical carbon dioxide (sCO2) Brayton cycle is used in lots of applications over a wide temperature range, such as solar thermal power generation, nuclear power, and WHR. What’s more, sCO2 Brayton cycle has many advantages, including the compactness of cycle layout, compact structure of turbomachinery, water conservation, and good system economy. Meanwhile, CO2 has characteristics of nonpoisonous and accessibility. The properties of CO2 near the critical point can be used to reduce compressor power consumption and improve cycle efficiency. When the cycle highest temperature is over 753.15 K, the efficiency of sCO2 Brayton cycle is higher than the steam Rankine cycle. To achieve the same efficiency, the highest temperature of steam Rankine cycle needs to be a higher level, which is difficult to achieve due to material constraints. At the same power level, the volume and complexity of the sCO2 Brayton cycle are much smaller than these of the steam Rankine cycle. Based on these, sCO2 Brayton cycle may be more suitable to recover high-temperature waste heat from gas turbine.
Surface temperature measurement of gas turbine combustor using temperature-indicating paint
Published in International Journal of Ambient Energy, 2022
M. Arulprakasajothi, P. L. Rupesh
An internal combustion engine in which continuous combustion takes place is called gas turbine (or) combustion turbine. The system consists of a compressor, a turbine and a combustion chamber. The Brayton cycle is the air standard cycle for the operation of a gas turbine engine (Lempereur, Andral, and Prudhomme 2008; Bird et al. 1998). The compressed atmospheric air from the compressor is sent to the combustion chamber where the fuel is injected (or) sprayed. The injection of fuel with the high pressurised air leads to combustion which produces high pressurised gases (Neely and Riesen 2008; Bird et al. 1998). These gases with high pressure undergo expansion in the turbine which produces work. An industrial gas turbine with the above parts has been shown in Figure 1.