scholarly journals Finite Time Analysis of Endoreversible Combined Cycle Based on the Stefan-boltzmann Heat Transfer Law

2020 ◽  
Vol 4 (1) ◽  
pp. 25
Author(s):  
Amir Ghasemkhani ◽  
Said Farahat ◽  
Mohammad Mahdi Naserian
Keyword(s):  
Heat Transfer ◽  
Finite Time ◽  
Combined Cycle ◽  
Time Analysis

A Comparative Evaluation of Advanced Combined Cycle Alternatives

1991 ◽  
Vol 113 (2) ◽  
pp. 190-197 ◽  
Author(s):  
O. Bolland
Keyword(s):  
Heat Transfer ◽  
Steam Turbine ◽  
Comparative Evaluation ◽  
Exergy Analysis ◽  
Combined Cycle ◽  
Heat Transfer Area ◽  
Turbine Condenser ◽  
Pressure Cycle ◽  
Steam Turbine Condenser ◽  
Exergy Balance

This paper presents a comparison of measures to improve the efficiency of combined gas and steam turbine cycles. A typical modern dual pressure combined cycle has been chosen as a reference. Several alternative arrangements to improve the efficiency are considered. These comprise the dual pressure reheat cycle, the triple pressure cycle, the triple pressure reheat cycle, the dual pressure supercritical reheat cycle, and the triple pressure supercritical reheat cycle. The effect of supplementary firing is also considered for some cases. The different alternatives are compared with respect to efficiency, required heat transfer area, and stack temperature. A full exergy analysis is given to explain the performance differences for the cycle alternatives. The exergy balance shows a detailed breakdown of all system losses for the HRSG, steam turbine, condenser, and piping.

Improved MSMGFSK Models Apply to Gas Radiation Heat Transfer Calculation of Exhaust System of TBCC

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Haiyang Hu ◽  
Qiang Wang
Keyword(s):  
Heat Transfer ◽  
Gas Flow ◽  
Thermal Emission ◽  
Radiation Heat Transfer ◽  
Exhaust System ◽  
Combined Cycle ◽  
Large Temperature ◽  
Radiation Heat ◽  
Full Spectrum ◽  
Radiation Emission

The multiscale multigroup full-spectrum k-distribution (MSMGFSK) model was improved to adapt to radiation heat transfer calculations of combustion gas flow field with large temperature and pressure gradient. The improvements in calculation accuracy resulting from new sorting strategy of the spectral absorption coefficients were validated using a series of semi-1D problem in which strong temperature, pressure, and mole fraction inhomogeneities were present. A simpler method to attain compatibility between the MSMGFSK model and the gray-wall radiation emission has been established and validated. Finally, estimates are given for the calculation of wall radiation heat transfer characteristics and thermal emission imaging of the exhaust system of the parallel turbine-based combined cycle (TBCC) engine, using finite volume method (FVM) and ray trace method (RT), respectively.

scholarly journals A Useful Equation for Gas Turbine Design

2018 ◽  
Vol 140 (03) ◽  
pp. S52-S53
Author(s):  
Lee S. Langston
Keyword(s):  
Heat Transfer ◽  
Heat Conduction ◽  
Gas Turbine ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Brayton Cycle ◽  
Nonlinear Superposition ◽  
Transient Conditions ◽  
One Dimensional ◽  
Turbine Design

This article presents three different gas turbine phenomena and design cases. The sketch in the article shows a schematic of a combined cycle powerplant consisting of a Brayton cycle (gas turbine) whose exhaust provides energy to a Rankine cycle (steam turbine). Frequently, one can use simple but exact one-dimensional (1D) heat conduction solutions to estimate the heat loss or gain of gas turbine components under transient conditions. These easy-to-use solutions are found in most undergraduate heat transfer texts. The article suggests that those three widely different gas turbine phenomena and design cases all have the simple, nonlinear superposition form.

Research on Heat-Transfer and Cooling Performance of Gas Turbine Endwall

2017 ◽  
Author(s):  
Kazuto Kakio ◽  
Y. Kawata
Keyword(s):  
Heat Transfer ◽  
Pressure Gradient ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Power Plants ◽  
Leading Edge ◽  
Horseshoe Vortex ◽  
Combined Cycle ◽  
Inlet Temperature ◽  
Cooling Performance

Recently, the number of gas turbine combined cycle plants is rapidly increasing in substitution of nuclear power plants. The turbine inlet temperature (TIT) is being constantly increased in order to achieve higher efficiency. Therefore, the improvement of the cooling technology for high temperature gas turbine blades is one of the most important issue to be solved. In a gas turbine, the main flow impinging at the leading edge of the turbine blade generates a so called horseshoe vortex by the interaction of its boundary layer and generated pressure gradient at the leading edge. The pressure surface leg of this horseshoe vortex crosses the passage and reaches the blade suction surface, driven by the pressure gradient existing between two consecutive blades. In addition, this pressure gradient generates a crossflow along the endwall. This all results into a very complex flow field in proximity of the endwall. For this reason, burnouts tend to occur at a specific position in the vicinity of the leading edge. In this research, a methodology to cool the endwall of the turbine blade by means of film cooling jets from the blade surface is proposed. The cooling performance and heat transfer coefficient distribution is investigated using the transient thermography method. CFD analysis is also conducted to know the phenomena occurring at the end wall and calculate the heat transfer distribution.

Effect ZOF heat transfer law on finite-time exergoeconomic performance of carnot heat pump

1998 ◽  
Vol 39 (7) ◽  
pp. 579-588 ◽  
Author(s):  
Chih Wu ◽  
Lingen Chen ◽  
Fengrui Sun
Keyword(s):  
Heat Transfer ◽  
Heat Pump ◽  
Finite Time

Optimization Analysis of Ship Steam Power System with Finite-Time Thermodynamics Theory

2012 ◽  
Vol 271-272 ◽  
pp. 1062-1066
Author(s):  
Zhi Guo Wei ◽  
Hai Kun Tao ◽  
Yong Li
Keyword(s):  
Heat Transfer ◽  
Power System ◽  
Finite Time ◽  
Influence Factors ◽  
Design Parameters ◽  
Carnot Cycle ◽  
Finite Time Thermodynamics ◽  
Steam Power ◽  
Cycle System ◽  
Steam Power System

A basic model with both property of thermodynamic and heat transfer is obtained by simplifying the prime process of ship Steam Power System (SPS), which is converted into endoreversible Carnot Cycle by the introduction of mean temperature in the cycle process. The design parameters is analyzed and optimized in the view point of finite time thermodynamics (FTT) and entropy generation minimization. Results show that, the temperature ratio (α) and the heat transfer parameter ratio (β) of heat source and heat sink are two important influence factors of cycle system performance, and the increase of α and decrease of β will redound to the reduction of irreversible loss and enhancement of power output.

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