2019-05-22T05:29:38Z
http://jhmtr.journals.semnan.ac.ir/?_action=export&rf=summon&issue=384
Journal of Heat and Mass Transfer Research
JHMTR
2345-508X
2345-508X
2017
4
2
Thermo-Economic Analysis of Applying Cooling System Using Fog on GE-F5 Gas Turbines (Case Study)
Seyed Mehdi
Arabi
Mohammad
Aminy
Hossein
Ghadamian
Hassan Ali
Ozgoli
Behzad
Ahmadi
Presently, nearly 26,000 MW gas power plant and nearly 16,000 MW of combined cycle has been installed in the country. But their power output in summer reduces to a minimum, where most demand is required, compared to the winter season. The main reason for that is gas turbine dependence on the ambient air temperature. Since most of our country has warm and dry climates, cooling down the input air to the compressor by means of water evaporation is the simplest method.<br />In this paper, attempts have been made to investigate the thermos-dynamical and economical behavior of fog system on four units of GE-F5 applied in Shahid Zanbagh power plant. The results show that application of this method, causes increase in mass flow rate of the air input and reduces consuming work of compressor, where power production increases by 2.64 MW and the required water for each unit is equal to 0.761 kg/s, also the payback time for this system was calculated to be less than 3 years.
simulation
Overall Efficiency
Net Present Value
Off-design Analysis
Evaporative Cooling
2017
10
01
73
81
http://jhmtr.journals.semnan.ac.ir/article_2455_3597dbc5a817ccb11f307eb94652a052.pdf
Journal of Heat and Mass Transfer Research
JHMTR
2345-508X
2345-508X
2017
4
2
Effect of baffle oientation on shell tube heat exchanger performance
Hamed
Uosofvand
Ali Akbar
Abbasian Arani
Ali
Arefmanesh
In this paper, fluid flow and heat transfer in the laboratory (small size) shell tube heat exchanger are analysed by computational fluid dynamic software. In this type of shell tube heat exchanger baffles with different angles of rotation: 00 (horizontal segmental baffle), 150 (from horizontal), 300, 450, 600, 750, 900 (vertical segmental baffle) is used. Effect of baffle orientation on shell tube heat exchanger performance is investigated. The flow domain is meshed by three-dimensional tetrahedral elements. The obtained result has a good agreement with the analytical method (Bell method) and experimental data in the literature. By comparing the pressure drop, heat transfer and heat transfer versus pressure drop (Q/ P) at same flow rate, the shell tube heat exchanger with orientation of (900) have better performance than other angles of baffle orientation. decrease pressure drop 26%, 4.1%, 17.6%, 24.42%, 14% rather than 150, 300, 450 ,600,750 ,00 angle of orientation respectively. That show have better performance than other angles of baffle orientation. So by reducing pressure drop with maintaining heat transfer rate, the operating cost reducing that can be best choice among other models.
shell tube heat exchanger
Baffle
Pressure drop
Heat Transfer
2017
10
01
83
90
http://jhmtr.journals.semnan.ac.ir/article_2526_33dbf1a9d31a9be9b35b3cef13ed44a0.pdf
Journal of Heat and Mass Transfer Research
JHMTR
2345-508X
2345-508X
2017
4
2
Unsteady boundary layer flow of a Casson fluid past a wedge with wall slip velocity
G
Sarojamma
K
Sreelakshmi
B
Vasundhara
In this paper an analysis is presented to understand the effect of non–Newtonian rheology, velocity slip at the boundary, thermal radiation, heat absorption/generation and first order chemical reaction on unsteady MHD mixed convective heat and mass transfer of Casson fluid past a wedge in the presence of a transverse magnetic field with variable electrical conductivity. The partial differential equations governing the flow with the pertinent boundary conditions are solved numerically. The computational results are presented graphically for different values of the non-dimensional parameters occurred in the analysis. The results for particular cases are compared with the published results available in literature and are found to be in excellent agreement. Present analysis indicates that the Casson parameter representing the non-Newtonian rheology has an increasing influence on velocity and temperature. The point of flow separation is found for negative values of wedge angle parameter. The radiation parameter enhances the rate of heat transfer. The mass transfer rate is reduced with chemical reaction parameter and Schmidt’s number.
Casson fluid
Heat and mass transfer
Unsteady wedge flow
Chemical reaction
2017
10
01
91
102
http://jhmtr.journals.semnan.ac.ir/article_2527_76c539f3512e5821cb4f8702e60fa0af.pdf
Journal of Heat and Mass Transfer Research
JHMTR
2345-508X
2345-508X
2017
4
2
Fluid flow and heat transfer characteristics in a curved rectangular duct using Al2O3-water nanofluid
Ashok
Barik
Binodini
Nayak
In the present research, the laminar forced convective heat transfer and fluid flow characteristics for Al2O3-water nanofluid flowing in different bend (i.e., 180o and 90o) pipes have been investigated numerically in a three-dimensional computational domain using the finite volume technique. The effects of different pertinent parameters, such as the Reynolds number of the duct, volume fraction of the nanoparticle, the diameter of the nanoparticle, aspect ratio of the duct and the duct bend angle on the hydrodynamic and thermal characteristics of the flow has been presented. It is observed that the heat transfer is augmented by replacing conventional fluid by Al2O3-water nanofluid. The nanoparticle volume fraction is found to be an important parameter to increase the heat transfer in the bend pipe. It is also observed that the thermo-hydraulic characteristics of the flow changes with the duct aspect ratio, and the heat transfer rate is improved with aspect ratio. The heat transfer with a 180o bend pipe is obtained to be higher than a 90o bend pipe at a particular value of volume fraction and Reynolds number. Moreover, the present computed Nusselt number for 180o bend pipe of rectangular cross-section has been validated with the existing literature. validated with the existing literature.
Nanofluid
forced convection
180o return bend pipe
Aspect Ratio
2017
10
01
103
115
http://jhmtr.journals.semnan.ac.ir/article_2606_938e0ba6023b9ca3b2d86e37aeb4993b.pdf
Journal of Heat and Mass Transfer Research
JHMTR
2345-508X
2345-508X
2017
4
2
Analytical and numerical investigation of heat and mass transfer effects on magnetohydrodynamic natural convective flow past a vertical porous plate
Srinivasa Raju
Rallabandi
Anitha
G
Jithender Reddy
G
The aim of this investigation is to study the effect of hall current on an unsteady natural convective flow of a viscous, incompressible, electrically conducting optically thick radiating fluid past a vertical porous plate in the presence of a uniform transverse magnetic field. The Rosseland diffusion approximation is used to describe the radiative heat flux in the energy equation. Analytical and numerical solutions of the coupled governing partial differential equations for the fluid velocity, fluid temperature and fluid concentration profiles are obtained by perturbation and finite element techniques respectively. The effects of the various dimensionless engineering parameters viz., Grashof number for heat and mass transfer, Magnetic field parameter, Prandtl number, Schmidt number, Thermal radiation parameter and Hall parameter entering into the problem on the primary and secondary velocities, temperature and concentration profiles throughout the boundary layer are investigated through graphs. The expressions of skin-friction, Nusselt number and Sherwood number are derived and represented through tabular form. The results reveal that the flow field and the temperature distribution are greatly influenced by thermal radiation parameter. Furthermore, the limiting cases are obtained and are found to be in good agreement with the previously published results.
Heat and mass transfer
Natural convection
Hall current
Porous medium
finite element method
Perturbation technique
2017
10
01
117
133
http://jhmtr.journals.semnan.ac.ir/article_2633_7e8a71c479ed92604667c739e19e1592.pdf
Journal of Heat and Mass Transfer Research
JHMTR
2345-508X
2345-508X
2017
4
2
Effects of variations in magnetic Reynolds number on magnetic field distribution in electrically conducting fluid under magnetohydrodynamic natural convection
Mohsen
Pirmohammadi
In this study the effect of magnetic Reynolds number variation on magnetic distribution of natural convection heat transfer in an enclosure is numerically investigated. The geometry is a two dimensional enclosure which the left wall is hot, the right wall is cold and the top and bottom walls are adiabatic. Fluid is molten sodium with Pr=0.01 and natural convection heat transfer for Rayleigh number, Ra=105 , and magnetic Reynolds numbers 10-1, 10-3 and 10-5 are considered and the governing equations including continuum, momentum, energy and magnetic induction are solved together concurrent. The numerical method finite volume and simpler algorithm for coupling the velocity and pressure is used. The results show for high magnetic Reynolds number the non-dimensional magnetic field in X and Y directions approximately are constant because diffusion of magnetic Reynolds number is more than advection but as magnetic Reynolds number increases the magnetic field in enclosure is not equal to applied magnetic field and is not constant and deviation from one is increased so that for Rem=10-1 the non-dimensional magnetic field in X direction from 0.09 to 6.6 and in Y direction from -1.164 to 4.05 changes.
Magnetic Reynolds number
Natural convection
Magnetic field
2017
10
01
149
155
http://jhmtr.journals.semnan.ac.ir/article_2703_579271ec309bafa338bc1aa3019ccc8b.pdf
Journal of Heat and Mass Transfer Research
JHMTR
2345-508X
2345-508X
2017
4
2
Thermodynamic analysis of a magnetohydrodyamic oldroyd 8-constant fluid in a vertical channel with heat source and slippage
Jacob
Gbadeyan
Tunde
Yusuf
Thermodynamic analysis of a steady state flow and heat transfer of an Oldroyd 8-constant fluid with effect of heat source, velocity slip and buoyancy force under tranverse a magnetic field is is carried out in this paper. The model for momentum and energy balance is tackled numerically using Method of Weighted Residual (MWR). Partition method is used to minimize the associated residuals. The results obtained were compared with that obtained using inbuilt numerical solver in MAPLE 18 to validate the method used and the convergence of the method is discussed. The results obtained from the momentum and energy balance were used to compute the entropy generation rate and the irreversibility ratio. The effects of controlling parameters such as non-Newtonian parameters, slip parameters, Grashoff number parameter, Brinkmann number, Hartmann, heat source parameter on the non dimensional velocity, temperature, entropy generation rate and irreversibility ratio are presented graphically and discussed. It is observed that irreversibility due to fluid friction dominates over the heat transfer when the non Newtonian parameter is kept constant for various values of , while irreversibility due to heat transfer dominate over fluid friction for various values of with fixed value .
: Oldroyd 8-constant fluid
Entropy Generation
Bouyancy effect
Heat source
Bejan number
2017
10
01
135
148
http://jhmtr.journals.semnan.ac.ir/article_2993_f3ab1e9594b96863ecf2ac97b4e4ea91.pdf