Modares Mechanical Engineering

Modares Mechanical Engineering

An experimental energy and exergy analysis of uniform and step heat flux effects on heat transfer over of circular cross-section tube

Authors
Abazar Abadeh 1
Mohammad javad Maghrebi 2
1 Mechanical department/ engineering faculty/ Ferdowsi university of mashhad
2 Ferdowsi Uni. of Mashhad
Abstract
Heat transfer enhancement is widely applicable in various industries, specifically in heat exchangers. Optimizing of heat transfer in the absence of increased pumping energy will result in increased of total efficiency in different systems. In this paper, forced convection heat transfer and fluid flow of fully developed laminar regime in a horizontal tube under uniform and non-uniform step heat fluxes is investigated experimentally. The effect of uniform, non-uniform increasing and decreasing applied heat fluxes on heat transfer and fluid flow are investigated. The effect of various parameters on heat transfer and fluid flow characteristics in these models are reported. Uncertainty analysis is performed and acceptable maximum of 1.8 percent is acquired. The primary results compared to well-known Shah and London equation for validation and maximum error of 8.5 percent is reported. In the present paper, Energy and exergy are two approach of analyzing. Convection heat transfer coefficient enhancement of 19.3 and 22.3 percent compared with model 1 are reported for model 2 and 3 respectively, in energy analysis. Furthermore, in this paper, exergy analysis is done and irreversibility values of 0.0887, 0.0803 and 0.1037 are reported for model 1, model 2 and model 3 respectively. Finally, it is concluded that the model number 3 is the best way to enhance heat transfer because of the maximum averaged Nusselt number and the minimum entropy generation values
Keywords
Heat Flux
Heat transfer coefficient enhancement
Fluid Flow
Exergy
energy

Subjects

10- مراجع
[1] D. Wen, G. Lin, S. Vafaei, K. Zhang, Review of nanofluids for heat transfer applications, Particuology, Vol. 7, No. 2, pp. 141-150, 2009.
[2] H. Yapıcı, B. Albayrak, Numerical solutions of conjugate heat transfer and thermal stresses in a circular pipe externally heated with non-uniform heat flux, Energy Conversion and Management, Vol. 45, No. 6, pp 927–937, 2004.
[3] J. A. Esfahani, P. B. Shahabi, Effect of non-uniform heating on entropy generation for the laminar developing pipe flow of a high Prandtl number fluid, Energy Conversion and Management, Vol. 51, No. 11, pp. 2087–2097, 2010.
[4] Y. Abbassi, M. Talebi, A. S. Shirani, J. Khorsandi, Experimental investigation of TiO2/Water nanofluid effects on heat transfer characteristics of a vertical annulus with non-uniform heat flux in non-radiation environment, Annals of Nuclear Energy, Vol. 69, No. 1, pp. 7–13, 2014.
[5] X. W. Zhu, J. Q. Zhao, L. Zhu, Heat transfer fluctuation in a pipe caused by axially non-uniform heat distribution, Applied Thermal Engineering, Vol. 103, No. 1, pp. 314–322, 2016.
[6] C. M. Cruz, O. Flores, D. Santana, M. G. Villalba, Heat transfer and thermal stresses in a circular tube with a non-uniform heat flux, International Journal of Heat and Mass Transfer, Vol. 96, No.1, pp. 256–266, 2016.
[7] M. Fakoor-Pakdaman, M. Andisheh-Tadbir, M. Bahrami, Unsteady laminar forced-convective tube flow under dynamic time-dependent heat flux, Journal of Heat Transfer, Vol. 136, No. 4, pp. 041706-1 to 041706-10, 2014.
[8] J. Padet, Transient convective heat transfer, Journal of the Brazilian Society of Mechanical Sciences and Engineering, Vol. 27, No. 1, pp. 74-96, 2005.
[9] S. V Patankar, S. Ramadhyani, E. M. Sparrow, Effect of circumferentially nonuniform heating on laminar combined convection in a horizental tube, Jornal of Heat Transfer, Vol. 100, No. 1, pp. 63-70, 1978.
[10] C. Changa, X. Lia, Q.Q. Zhang , Experimental and numerical study of the heat transfer characteristics in solar thermal absorber tubes with circumferentially non-uniform heat flux, Energy Procedia, Vol. 49, No.1, pp. 305 – 313, 2014.
[11] J. Wang, W. Liu, Z. Liu, The application of exergy destruction minimization in convective heat transfer optimization, Applied Thermal Engineering, Vol. 88, No.1, pp. 384-390, 2015.
[12] J. Wang, Z. Liu, F. Yuan, W. Liu, G. Chen, Convective heat transfer optimization in a circular tube based on local exergy destruction minimization, International Journal of Heat and Mass Transfer, Vol. 90, No. 1, pp. 49–57, 2015.
[13] M. Mehrali, E. Sadeghinezhad, M. A. Rosen, A. R. Akhiani, S. T. Latibari, M. Mehrali, H. S. C. Metselaar, Heat transfer and entropy generation for laminar forced convection flow of graphene nanoplatelets nanofluids in a horizontal tube, International Communications in Heat and Mass Transfer, Vol. 66, No. 1, pp. 23–31, 2015.
[14] V. Bianco, O. Manca, S. Nardini, Entropy generation analysis of turbulent convection flow of Al2O3–water nanofluid in a circular tube subjected to constant wall heat flux, Energy Conversion and Management, Vol. 77, No. 1, pp. 306–314, 2014.
[15] A. C. Rapier, forced convection heat transfer in a circular tube with non-uniform heat flux around the circumference, International Jornal of Heat and Mass Transfer, Vol. 15, No. 3, pp. 527-537, 1972.
[16] C. Changa, C. Xu, Z. Y. Wu, X. Li, Q. Q. Zhang, Z. F. Wang, Heat transfer enhancement and performance of solar thermal absorber tubes with circumferentially non-uniform heat flux, Energy Procedia, Vol. 69, No. 1, pp. 320 – 327, 2015.
[17] Z. J. Zheng, Y. He, Y. He, K. Wang, Numerical optimization of catalyst configurations in a solar parabolic trough receiver–reactor with non-uniform heat flux, Solar Energy, Vol. 122, No. 1, pp. 113–125, 2015.
[18] Z. J. Zheng, M. J. Li, Y. L. He, Thermal analysis of solar central receiver tube with porous inserts and non-uniform heat flux, Applied Energy, Vol. 185, No. 2, pp. 1152-1161, 2017.
[19] M. Goharkhah, A. Salarinia, M. Ashjaee, M.Shahabadi, Convective heat transfer characteristics of magnetite nanofluid under the influence of constant and alternating magnetic field, Powder Technology, Vol. 274, No. 1, pp. 258–267, 2015.
[20] Jr. kenneth Wark, Advanced Thermodynamics for Engineers, pp. 60-74, McGraw-Hill Education,1994.
[21] M. Hosseinzadeh, A. Salari, M. Sardarabadi, M. Passandideh-Fard, A. Akbarzadeh, Numerical and experimental investigation of optimization of photovoltaic thermal system, using taguchi method, Modares Mechanical Engineering, Vol. 17, No. 8, pp. 57-88, 2017. (in Persian)
[22] L. S. Sundar, M. T. Naik, K. V. Sharma, M. K. Singh, T. C. S. Reddy, Experimental investigation of forced convection heat transfer and friction factor in a tube with Fe3O4 magnetic nanofluid, Experimental Thermal and Fluid Science, Vol. 37, No. 1, pp. 65-71, 2012.
Modares Mechanical Engineering
Volume 18, Issue 4
August 2018
Pages 201-210