scholarly journals ENTROPY GENERATION AND TEMPERATURE GRADIENT HEAT SOURCE EFFECTS ON MHD COUETTE FLOW WITH PERMEABLE BASE IN THE PRESENCE OF VISCOUS AND JOULES DISSIPATION

2020 ◽  
Vol 15 ◽  
Author(s):  
K.S. Balamurugan ◽  
N. Udaya Bhaskara Varma ◽  
J.L. Ramaprasad
Keyword(s):  
Temperature Gradient ◽  
Heat Source ◽  
Couette Flow ◽  
Entropy Generation ◽  
Source Effects ◽  
Mhd Couette Flow

scholarly journals Heat transfer and entropy generation analysis in a horizontal channel filled with a permeable medium in the presence of aligned magnetic field and temperature gradient heat source

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
K. S. Balamurugan ◽  
N. Udaya Bhaskara Varma ◽  
J. L. Ramaprasad
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Shear Stress ◽  
Temperature Gradient ◽  
Heat Source ◽  
Entropy Generation ◽  
Fluid Velocity ◽  
Horizontal Channel ◽  
Bejan Number ◽  
Aligned Magnetic Field

AbstractThe current investigation is concerned with heat transfer and entropy generation analysis in a horizontal channel brimming with porous medium in the existence of aligned magnetic field, viscous and joules dissipation and temperature gradient heat source. The boundary conditions are treated as constant values for velocity and temperature at lower and upper walls. An explicit solution of governing equations has been attained in closed system. The repercussions of pertinent parameters on the fluid velocity, temperature, entropy generation and Bejan number are conferred and scrutinized through graphs in detail. Additionally the expressions for shear stress and the rate of heat transfer coefficients at the channel walls are derived and results obtained are physically interpreted through tables. From the conquered results, it is addressed that Brinkman number Br enhances boundary layer thickness. Entropy generation increases with intensifying values of $$M$$ M , aligned angle ϕ, temperature gradient heat source parameter Q, characteristic temperature ration $$\omega$$ ω and permeability parameter K. The shear stress is same at both the lower and upper walls.

Theoretical and experimental investigation of an organic Rankine cycle for a waste heat recovery system

2009 ◽  
Vol 223 (5) ◽  
pp. 523-533 ◽  
Author(s):  
W Gu ◽  
Y Weng ◽  
Y Wang ◽  
B Zheng
Keyword(s):  
Heat Source ◽  
Entropy Generation ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Entropy Generation Rate ◽  
Working Fluid ◽  
Total Entropy ◽  
Waste Heat Recovery System ◽  
Cycle Efficiency

This article describes and evaluates an organic Rankine cycle (ORC) for a waste heat recovery system by both theoretical and experimental studies. Theoretical analysis of several working fluids shows that cycle efficiency is very sensitive to evaporating pressure, but insensitive to expander inlet temperature. Second law analysis was carried out using R600a as a working fluid and a flow of hot air as a heat source, which is not isothermal, along the evaporator. The result discloses that the evaporator's internal and external entropy generation is the main source of total entropy generation. The effect of the heat source temperature, evaporating pressure, and evaporator size on the entropy generation rate is also presented. The obtained useful power is directly linked to the total entropy generation rate according to the Gouy—Stodola theorem. The ORC testing system was established and operated using R600a as a working fluid and hot water as a heat source. The maximum cycle efficiency of the testing system is 5.2 per cent, and the testing result also proves that cycle efficiency is insensitive to heat source temperature, but sensitive to evaporating pressure. The entropy result also shows that internal and external entropy of the evaporator is the main source of total entropy generation.

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