Parametric study of heat recovery from test engine cell applying the Rankine cycle with organic fluid
Farzad
Mohammad Khani
دانشجوی دکتری، دانشکده مهندسی مکانیک، دانشگاه تبریز
author
Naser
Shokati
Faculty of Mechanical Engineering, Tabriz University, Tabriz, Iran
author
Navid
Farokhi
Young Research Club, Ilkhchi branch, Islamic Azad Univeristy, Ilkhchi, Iran
author
Faramarz
Ranjbar
Faculty of Mechanical Engineering, Tabriz University, Tabriz, Iran
author
text
article
2015
per
To evaluate the performance of an engine, it is needed to test engine experimentally. A Large amount of energy is wasted in the engine test cell. In the present work, in order to generate power from the waste heat, an Organic Rankine Cycle (ORC) is used. The waste heat is recovered in three separate heat exchangers (preheater, evaporator and superheater). These heat exchangers are separately designed, and the whole system is analyzed from the energy and exergy viewpoints. Finally, a parametric study is performed to investigate the effects of heat recovery temperature characteristics on important thermodynamic and heat transfer parameters. The results show that applying the ORC, recovers the heat losses equivalent to 8.85% of the engine power.
نشریه پژوهشی مهندسی مکانیک ایران
ISME
2538-4775
17
v.
2
no.
2015
6
22
http://jmep.isme.ir/article_25863_8508c577c1e6bb0249d9aac40eea650b.pdf
Comprehensive numerical study of difference between the aerodynamic coefficients in symmetrical classic airfoil with two different assumptions of transitional and fully turbulent flows in both of compressible and incompressible regimes
Mehdi
Sanienejad
پژوهشکده مبین
author
text
article
2015
per
In the following paper, the accuracy of full turbulent K-e and transitional K-w models in external aerodynamic capturing of NACA0012 in both incompressible regime (Re number of 6 million) and subsonic compressible regime (Mach number of 0.3 to 0.9 and Re number of 1 million to 100 million) have been comprehensively investigated until using comparison between both results, the differences between full turbulent and transitional flow (combined fully laminar + transition region + fully turbulent) assumptions in aerodynamic coefficients specified accurately. Among these investigations, some sorts of sensitivity analysis, including changes in free-stream Mach number, free-stream Reynolds number, free-stream angle of attack, grid density and free stream turbulence level have been done. Also the effects of transition inception point and affecting parameters, and the magnitude of the conformity between numerical results and theoretical concepts about transition and related effective parameters on the magnitude of lift, drag, lift-slope, pressure distribution, and pressure/friction lift-and-drag coefficients have been investigated in detail. To confirm the validity and the accuracy of the results, the numerical results have been compared with some published references. [1]Saniei Nejad, M., “Fundamentals of Turbulent Flows and Turbulence Modeling”, Danesh Negar Pub. In Persian (2009). [2]Gregory, N., and Wilby, P.G., “NPL 9615 and NACA 0012 - A Comparison of Aerodynamic Data”, Aeronautical Research Council, London, (1973). [3]Jameson, A., and Mavriplis, D., “Finite Volume Solution of the Two-dimensional Euler Equations on a Regular Triangular Mesh”, AIAA-85-0435, Reno, Nevada, January 14-17 (1985). [4]McCroskey, W.J., “A Critical Assessment of Wind Tunnel Results for the NACA0012 Airfoil”, NASA Technical Memorandum 100019, USAAVSCOM Technical Report 87-A-5, October (1987). [5]Maksymiuk, C.M., and Pulliam, T.H., “Viscous Transonic Airfoil Workshop Results using ARC2D”, AIAA-87-04 15, AIAA 25th Aerospace Sciences Meeting, Reno, Nevada, January 12-15 (1987). [6]Arias, O., Falcinelli, O., Fico, N., and Elaskar, S., “Finite Volume Simulation of a Flow over a NACA 0012 using Jameson, Maccormack, Shu and Tvd Esquemes”, Mecanica Computacional, Vol. XXVI, pp. 3097-3116, Argentina, Oct. (2007). [7]Barter, G.E., “Shock Capturing with PDE-based Artificial Viscosity for an Adaptive, Higher-order Discontinuous Galerkin Finite Element Method”, Doctor of Philosophy Thesis, Massachusetts Institute of Technology, USA, (2008). [8]Schook, R., “Bypass Transition Experiments in Subsonic Boundary Layers”, Eindhoven University Press Facilities, The Netherlands, (2000). [9]Mayle, R.E., “The Role of Laminar-turbulent Transition in Gas Turbine Engines”, Journal of Turbomachinery, Vol. 113, No. 4, pp. 509-536, Oct, (1991). [10] Sveningsson, A., “Transition Modelling – A Review”, Department of Thermo and Fluid Dynamics, Chalmers University of Technology, Gothenburg, Sweden, Oct. (2006). [11] Menter, F.R., “Two-equation Eddy-viscosity Turbulence Models for Engineering Applications”, AIAA J., Vol. 32, No. 8, pp. 1598-1605, August, (1994). [12] Wilcox, D.C., “Turbulence Modeling for CFD”, DCW Industries, Inc., La Canada, California, (1998). [13] Hutchinson, B.R., and Raithby, G.D., “A Multigrid Method Based on the Additive Correction Strategy”, Numerical Heat Transfer, Vol. 9, pp. 511-537, (1986). [14] Weiss, J.M., Maruszewski, J.P., and Smith, W.A., “Implicit Solution of Preconditioned Navier-Stokes Equations, using Algebraic Multigrid”, AIAA J., Vol. 37, pp. 29-36, (1999). [15] Rumsey, C.L., Smith, B.R., and Huang, G.P., “Description of a Website Resource for Turbulence Model Verification and Validation”, AIAA Paper 2010-4742 40th AIAA Fluid Dynamics Conference, Chicago, IL, June 28-July 1 (2010).
نشریه پژوهشی مهندسی مکانیک ایران
ISME
2538-4775
17
v.
2
no.
2015
23
67
http://jmep.isme.ir/article_25864_765f0d40b73b2f5040cae29e764cda93.pdf
Analytical and field study of environmental parameters affecting on performance of Heller cooling towers from economical point of view
Mohammadali
Ardakani
Associate professor, Department of Mechanical Engineering, Iranian research organization for science and technology
author
Foad
Farhani
Mechanical Engineering Department, Iranian Research Organization for Science and Technology, Tehran, Iran
author
Mohsen
Mazidi
Department of Mechanical Engineering, Iranian Research Organization for Science and Technology, Tehran, Iran
author
text
article
2015
per
Ambient temperature variations and cross winds are the most important environmental parameters affecting the performance of cooling towers, which can result in considerable economical losses to a power plant. In this paper, field and analytical study of these parameters and their effects on the performance of Heller cooling towers from economical point of view have been presented for a typical 240 MW power plant. Results show that at constant ambient temperature, with the increase in wind speed up to 6 m/s, the performance of the steam section of the power plant decreases by an average of 2.52%. Similarly, under still-air condition (no-wind condition), a 10 °C increase in the ambient temperature results in about 3.4% decrease in the performance of the steam section. The percentages of decrease in the performance of the steam section of the power plant are equivalent to reduction in the produced power amounting to 16.8 MW and 24 MW, respectively.
نشریه پژوهشی مهندسی مکانیک ایران
ISME
2538-4775
17
v.
2
no.
2015
68
82
http://jmep.isme.ir/article_25865_a36e070e1cc7cce822434302b832838a.pdf
Simulation of partial cavitation over the symmetrical circular and elliptical crosss sections using the boundary element method
Mehdi
Nowrozi
گروه مهندسی مکانیک، دانشگاه فردوسی مشهد، مشهد
author
Mohammad Hasan
Javarashkian
Department of Mechanical Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
author
Mahmood
Pasandide Fard
Department of Mechanical Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
author
text
article
2015
per
In this research a software is developed to simulate the partial cavitation over the axisymmetric and quasi three-dimensional bodies using a Boundary Element Method (BEM).According to desirable convergenceof axisymmetric simulation in BEM, first the axisymmetric cavitation flow is simulated and this result is used to simulate quasi three-dimensional bodies. In order to simulate the cavitation flow, the source and dipole rings are distributed on body and cavity boundaries, Using Green's theorem integral expression and to simulate closure of cavity, two models is used: simple closure model and re-entrant jet model. The constant length of the cavity is initial prediction and the cavitation number and shape of cavity are the main results of this simulation. The validation of solution, the Navier-Stokes equations based on mixture model is compared to BEM results in convergense and accuracy. Compression between this results and other experimental and numerical simulation show the ability of BEM in simulation of cavitation flows with desirable convergence and relatively good accuracy.
نشریه پژوهشی مهندسی مکانیک ایران
ISME
2538-4775
17
v.
2
no.
2015
83
106
http://jmep.isme.ir/article_25866_1d95121544611448d41d67863e244117.pdf
Performance enhancement of air coolers using the flow turbulator
Siroos
Saeb
دانشکده محیط زیست و انرژی، دانشگاه آزاد اسلامی واحد علوم تحقیقات تهران
author
Mohammadreza
Jafari Nasr
Faculty of Mechanical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
author
Mohammad
Ghadimi
Department of Mechanical Engineering, Roudehen Branch, Islamic Azad University, Roudehen, Iran
author
text
article
2015
per
Applications of heat transfer enhancement by tube inserts (turbulators) have been used in many industries such as power plants, refineries and petrochemicals plants. The main objective is typically viewed primarily as a means to improve and to intensify the thermal performance, size and capital cost reduction of heat exchangers and air coolers. This article introduces a procedure for considering of heat transfer enhancement in a typical air cooler using different turbulators such as Wire coils, Twisted tape and Wire matrixes. Due to increase of the effective surface area, increase of eddies and back mixing in fluid and consequently increase of heat transfer rate, the required heat transfer area is reduced significantly. The case study shows application of wire coil inserts is more effective than others and goes beyond the size reduction. The comparison is revealed that about 20 percent improvement in total cost for 10 years operation of the existing air cooler equipped with the turbulator
نشریه پژوهشی مهندسی مکانیک ایران
ISME
2538-4775
17
v.
2
no.
2015
107
124
http://jmep.isme.ir/article_25867_c45ee85e57360dac247efe248234c11a.pdf