Heat and Mass Transfer

, Volume 54, Issue 3, pp 715–726 | Cite as

Numerical investigation of heat transfer in annulus laminar flow of multi tubes-in-tube helical coil

  • S. A. Nada
  • H. F. Elattar
  • A. Fouda
  • H. A. Refaey
Original

Abstract

In the present study, a CFD analysis using ANSYS-FLUENT 14.5 CFD package is used to investigate the characteristics of heat transfer of laminar flow in annulus formed by multi tubes in tube helically coiled heat exchanger. The numerical results are validated by comparison with previous experimental data and fair agreements were existed. The influences of the design and operation parameters such as heat flux, Reynolds numbers and annulus geometry on the heat transfer characteristics are investigated. Different annulus of different numbers of inner tubes, specifically 1, 2, 3, 4 and 5 tubes, are tested. The Results showed that for all the studied annulus, the heat flux has no effect on the Nusselt number and compactness parameter. The annulus formed by using five inner tubes showed the best heat transfer performance and compactness parameter. Correlation of predicting Nusselt number in terms of Reynolds number and number of inner tubes are presented.

Nomenclature

ρw

Water density, kg/m3

μw

Water dynamic viscosity, N.s/m2

A

Annulus cross sectional area, m2

Ah

Rod heaters surfaces area, m2

Cp

Water specific heat, J/kg.K

D

Diameter of the outer tube, m

d

Heaters rod diameter, m

Dc

Helical coil of diameter, m

De

Dean number, dimensionless

Dh

Hydraulic diameter, m

h

Average coefficient of heat transfer, W/m2.K

H

Pitch, m

hAh

Factor to measure heat exchanger compactness, W/K

hx

Local coefficient of heat transfer, W/m2.K

kw

Thermal conductivity of water, W/m.K

L

Length of coil tube, m

w

Mass flow rate of water, kg/s

N

Number of inner rod heaters

Nu

Average Nusselt number, dimensionless

Pr

Prandtl number, dimensionless

q

Heat flux, W/m2

Q

Rate of heat transfer, W

R

Coil curvature ratio, dimensionless

Re

Reynolds number, dimensionless

Ts

Heater rods average surface temperature, oC

Tw

Average temperature of cooling water along the entire annulus volume, oC

Twi

Average temperature of inlet water, oC

Two

Average temperature of exit water, oC

Z

Number of the coil turns

References

  1. 1.
    Dean WR (1927) Note on the motion of fluid in a curved pipe. Philos Mag 20:208–223CrossRefMATHGoogle Scholar
  2. 2.
    Dravid AN, Smith KA, Merrill EW, Brian PLT (1971) Effect of secondary fluid motion on laminar flow heat transfer in helically coiled tubes. AICHE J 17(5):1114–1122CrossRefGoogle Scholar
  3. 3.
    Akiyama M, Cheng KC (1972) Laminar forced convection heat transfer in curved pipes with uniform wall temperature. Int J Heat and Mass Transfer 15:1426–1431CrossRefGoogle Scholar
  4. 4.
    Kalb CE, Seader JD (1983) Entrance region heat transfer in a uniform wall-temperature helical coil with transition from turbulent to laminar flow. Int J Heat and Mass Transfer 26(1):23–32CrossRefGoogle Scholar
  5. 5.
    Janssen LAM, Hoogendoorn CJ (1978) Laminar convective heat transfer in helical coiled tubes. Int J Heat and Mass Transfer 21:1197–1206CrossRefGoogle Scholar
  6. 6.
    Jayakumar JS, Mahajani SM, Mandal JC, Iyer KN, Vijayan PK (2010) CFD analysis of single-phase flows inside helically coiled tubes. Comput Chem Eng 34:430–446CrossRefGoogle Scholar
  7. 7.
    Prabhanjan DG, Rennie TJ, Raghavan GSF (2004) Natural convective heat transfer from helical coiled tubes. Int J Thermal Sciences 43:359–365CrossRefGoogle Scholar
  8. 8.
    Shokouhmand H, Salimpour MR, Akhavan-Behabadi MA (2008) Experimental investigation of shell and coiled tube heat exchangers using wilson plots. Int Commun Heat Mass Transfer 35:84–92CrossRefGoogle Scholar
  9. 9.
    Salimpour MR (2009) Heat transfer coefficients of shell and coiled tube heat exchangers. Exp Thermal Fluid Sci 33:203–207CrossRefGoogle Scholar
  10. 10.
    Ghorbani N, Taherian H, Gorji M, Mirgolbabaei H (2010) An experimental study of thermal performance of shell-and-coil heat exchangers. Int Commun Heat Mass Transfer 37:775–781CrossRefGoogle Scholar
  11. 11.
    Ghorbani N, Taherian H, Gorji M, Mirgolbabaei H (2010) Experimental study of mixed convection heat transfer in vertical helically coiled tube heat exchangers. Exp Thermal Fluid Sci 34:900–905CrossRefGoogle Scholar
  12. 12.
    Lu X, Zhang G, Chen Y, Wang Q, Zeng M (2015) Effect of geometrical parameters on flow and heat transfer performances in multi-stream spiral-wound heat exchangers. Appl Therm Eng 89:1104–1116CrossRefGoogle Scholar
  13. 13.
    Nada SA, Eid EI, Abd El Aziz GB, Hassan HA (2015) Performance enhancement of Shell and helical coil water coolers using different geometric and fins conditions. Heat Trans Asian Res:1–17.  https://doi.org/10.1002/htj.21180
  14. 14.
    Petrakis MA, Karahalios GT (1999) Fluid flow behavior in a curved annular conduit. Int J Non Linear Mech 34(1):13–35CrossRefMATHGoogle Scholar
  15. 15.
    Rennie TJ (2004) Numerical and experimental studies of a double-pipe helical heat exchanger, Ph.D. Dissertation, McGill University, Montreal, CanadaGoogle Scholar
  16. 16.
    Rennie TJ, Raghavan VGS (2005) Experimental studies of a double-pipe helical heat exchanger. Exp Thermal Fluid Sci 29:919–924CrossRefGoogle Scholar
  17. 17.
    Kumar S, Sharma SM, Nigam KDP (2006) Pressure drop and heat transfer study in tube-in-tube helical heat exchanger. Chem Eng Sci 61:4403–4416CrossRefGoogle Scholar
  18. 18.
    Louw WI (2002) The influence of annular tube contact in a helical-wound tube-in-tube heat exchanger. Master in mechanical engineering In the Faculty of Engineering of the Rand Afrikaans UniversityGoogle Scholar
  19. 19.
    Seyyedvalilu MH, Ranjbar SF (2015) The effect of geometrical parameters on heat transfer and hydrodynamics characteristics of helical exchanger. Int J Recent Adv Mech Eng (IJMECH) 4(1):35–46Google Scholar
  20. 20.
    Kharat NB, Jha RS (2009) Development of heat transfer coefficient correlation for concentric helical coil heat exchanger. Int J Thermal Sci 48:2300–2308CrossRefGoogle Scholar
  21. 21.
    Al Shaer WG (2010) Heat transfer and pressure drop characteristics of multi tubes-in-tube helically coiled heat exchanger, M. SC. Thesis, Benha University, EgyptGoogle Scholar
  22. 22.
    Nada SA, El Shaer WG, Huzayyin AS (2015) Performance of multi tubes in tube helically coiled as a compact heat exchanger. Heat Mass Transf 51(7):973–982CrossRefGoogle Scholar
  23. 23.
    Holman JP, Gajda WJ (1989) Experimental method for engineering. McGraw Hill, New YorkGoogle Scholar
  24. 24.
    Srinivasan PS, Nandapurkar SS, Holland FA (1968) Pressure drop and heat transfer in coils. Chem Eng 9:113–119Google Scholar

Copyright information

© Springer-Verlag GmbH Germany 2017

Authors and Affiliations

  • S. A. Nada
    • 1
  • H. F. Elattar
    • 1
  • A. Fouda
    • 2
  • H. A. Refaey
    • 3
  1. 1.Department of Mechanical Engineering, Benha Faculty of EngineeringBenha UniversityBenhaEgypt
  2. 2.Department of Mechanical Power Engineering, Faculty of EngineeringMansoura UniversityEl-MansouraEgypt
  3. 3.Department of Mechanical Engineering, Faculty of Engineering at ShoubraBenha UniversityCairoEgypt

Personalised recommendations