Modares Mechanical Engineering

Modares Mechanical Engineering

Evaporation behavior of R-600a considering exergy losses in horizontal smooth and enhanced tubes

Authors
hosein moradi 1
Maziar Shafaee 2
Mohammad Hossein Sabour 3
1 aerospace engineering,faculty of new sciences,tehran university,tehran,iran
2 University of Tehran
3 Chair of Aerospace Eng. Department
Abstract
In the present study, evaporation heat transfer and frictional pressure drops of refrigerant R-600a (iso-butane) inside a helically dimpled tube and a plain tube of internal diameter 8.3mm were measured and analyzed. All tests were performed at different vapor qualities up to 0.8 and average saturation temperatures ranging between 38 and 42℃. Refrigerant mass fluxes varied in the range of 114-368 kg/m2s. The inner surface of the helically dimpled tube has been designed and reshaped through three-dimensional material surface modifications consists of both shallow and deep protrusions which is placed evenly in helical directions on the tube wall. The experimental results show that the heat transfer coefficients of the dimpled tube are 1.29-2 times larger than a smooth tube with a pressure drop penalty just ranging between 7% and 103% larger than the smooth tube. Moreover, Performance Evaluation Criteria (PEC) dubbed Penalty Factor (PF) and Total Temperature Penalization (TTP) boiling inside a helically dimpled tube and a smooth tube were analyzed which are a convenient way to relate the two penalization components and provides a rational method to compare the exergy losses associated with frictional pressure drop and heat transfer coefficient.
Keywords
R-600a
evaporation
Performance Criterion
Exergy

Subjects

[1] M.Ziaei,M.Beigi."numerical study of heat transfer and pressure drop in forced convection nanofluid flow through an internally ribbed pipe".Journal of engineering modeling semnan university.Vol 16,No 49,pp.65-76,2017(in persian)
[2] L.Ming,et al. "Single phase heat transfer and pressure drop analysis of a dimpled enhanced tube." Applied Thermal Engineering Vol.101,pp. 38-46,2016
[3] L.Zhouhang, et al. "Effects of rib geometries and property variations on heat transfer to supercritical water in internally ribbed tubes." Applied Thermal Engineering Vol.70,pp.303-314,2015
[4] B. Guo, Si-pu, et al. "Condensation and evaporation heat transfer characteristics in horizontal smooth, herringbone and enhanced surface EHT tubes." International Journal of Heat and Mass Transfer Vol.85, pp.281-291,2015
[5] M.H.Shojaeeefard,A.Khalkhali,J.Zare,M.Tahani."Multi obejctive optimization of heat pipe thermal performance while using aluminium oxide nanofluid".Tarbiat moddares journal.Vol 14,No 1,pp.158-167.2014(in persian)
[6] M.A.Khairul,et al. "Heat transfer performance and exergy analyses of a corrugated plate heat exchanger using metal oxide nanofluids." International Communications in Heat and Mass Transfer Vol.50, pp.8-14,2014
[7] D.J.Kukulka,R.Smith. "Thermal-hydraulic performance of Vipertex 1EHT enhanced heat transfer tubes." Applied Thermal Engineering Vol.61,No.1, pp.60-66,2013
[8] F.Gupta, C.Anirudh, and M. Uniyal. "Review of heat transfer augmentation through different passive intensifier methods." IOSR Journal of Mechanical and Civil Engineering (IOSRJMCE) ISSN ,pp. 2278-1684,2012
[9] M.Goto,N.Inoue,N.Ishiwatari,"Condesation and evaporation heat transfer of R-410A inside internally grooved horizontal tubes:".International journal of refrigeration.Vol 24,No 7,pp.628-638,2012
[10] J.S.Brown,C.zilio,R.Brignoli,A,Cavallini."Heat transfer and pressure drop penalization terms during flow boiling of refrigerants".International journal of energy research.Vol 37,No 10,pp.1669-1679,2012
[11] S.Suresh ,M.Chandrasekar, and S. Chandra Sekhar. "Experimental studies on heat transfer and friction factor characteristics of CuO/water nanofluid under turbulent flow in a helically dimpled tube." Experimental Thermal and Fluid Science Vol.35,No.3,pp. 542-549,2011
[12] A.Cavallini,et al. "In-tube condensation performance of refrigerants considering penalization terms (exergy losses) for heat transfer and pressure drop." International Journal of Heat and Mass Transfer Vol.53,No.13, pp.2885-2896,2010
[13] J.R.Thome,L.Cheng,L.F.Raibatski."Flow boiling of amonia and hydrocarbons".Jornal of refrigeration.Vol 31,No 6,pp. 603-620,2010
[14] R.l.Web."Performance evaluation criteria fro use of ehanced heat transfer surfaces in heat exchanger design".Heat mass transfer.Vol 24,No 2,pp.715-726,2008
[15]N.Paisarn. "Second law analysis on the heat transfer of the horizontal concentric tube heat exchanger." International communications in heat and mass transfer Vol.33,No.8,pp.1029-1041,2006
[16] H.Honda,H.S.Wang,S.Nozu."A theoretical study of film condesation in horizontal microfines tubes".Jornal of heat transfer.Vol 55,No 6,pp.94-101,2004
[17] A.Cavallini."Heat transfer and energy efficiency for working fluids in mechanical refrigeration".Journal of refrigeration.Vol 6,No 6,pp.221-363,2002
[18]E.B.Ratts,JS,Brown."An experimental analysis of cycling in an automotive air conditioning system".Applied thermal engineering.Vol 20,No 11,pp 1039-1058,2000
Modares Mechanical Engineering
Volume 18, Issue 7
November 2018
Pages 5-9