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Wärme - und Stoffübertragung

, Volume 29, Issue 4, pp 211–217 | Cite as

Experimental investigations on a 1–2 heat exchanger with wire-wound tubes

  • C. B. Sobhan
  • K. T. Mohammed Kutty
  • M. Hannan
  • P. Krishtaiah
Originalarbeiten
  • 141 Downloads

Abstract

This paper deals with experimental investigations on a 1–2 shell and tube heat exchanger, to study the effect of spiral turbulators on its performance. The heat exchanger has its tubes wound with copper wire, so that the winding acts as an augmenting device. Experiments were conducted with various winding wire diameters and pitches and the heat transfer coefficients were evaluated for a wide range of temperature levels and flow rates of the shell side fluid. The experimental results are discussed in detail and correlations are proposed to predict the shell side Nusselt number of the exchanger with varying winding pitches and diameters. The existence of optimum winding is also discussed in this paper. The present results are based on over 250 experimental observations made in the laminar range of flow.

Keywords

Heat Transfer Transfer Coefficient Experimental Investigation Heat Transfer Coefficient Heat Exchanger 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Nomenclature

Ao

heat transfer surface area outside the tube, m2

Ai

heat transfer surface area inside the tube, m2

do

outer diameter of the tube, m

D

inner diameter of the shell, m

De

equivalent diameter of shell for heat transfer, m

dw

diameter of the winding wire, m

FT

LMTD correction factor [8]

hi

inside heat transfer coefficient, W/m2 K

ho

outside heat transfer coefficient, W/m2 K

ko

thermal conductivity of water outside tube, W/mK

L

length of the shell, m

lt

tube length, m

lw

length of the winding wire, m

LMTD

logarithmic mean temperature difference, K

m

mass flow rate of cold fluid, kg/h

N

number of tube passes

Nui

inside Nusselt number for the tube

Nuo

outside Nusselt number for the tube

Nuo*

outside Nusselt number, average over the temperature range

nt

number of tubes per pass

P

pitch of the winding wire, m

Prt

Prandtl number, tube side

Q

heat transfer rate, W

Ret

tube side Reynolds number

Res

shell side Reynolds number for heat transfer

ΔT

corrected mean temperature difference, K [8]

Thi

inlet temperature of hot water, °C

Tho

exit temperature of hot water, °C

Tii

inlet temperature of cold water, °C

Tco

exit temperature of cold water, °C

Uo

overall heat transfer coefficient, W/m2 K

Experimentelle Untersuchungen an einem 1–2-Wärmetauscher mit drahtumwickelten Rohren

Zusammenfassung

Diese Arbeit befaßt sich mit experimentellen Untersuchungen an einem 1–2-Zylindermantel/Rohrwärmetauscher und hat die Klärung des Einflusses von spiralförmigen Turbulenzpromotoren auf das Übertragungsverhalten zum Ziel. Die Rohre des Wärmetauschers sind mit Kupferdraht umwickelt, dessen Windungslagen den Austausch befördern. Die Experimente wurden mit verschiedenen Drahtdurchmessern und Steigungen durchgefürht und hieraus Wärmeübergangskoeffizienten in einem weiten Bereich der Temperaturniveaus und der Mengenströme des die Rohre umströmenden Fluids bestimmt. Die experimentellen Befunde werden eingehend diskutiert und Korrelationen zur Bestimmung der Nusselt-Zahl auf der Rohraußenseite in Abhängigkeit von Steigung und Durchmesser der Drahtwindungen angegeben. Die Ergebnisse basieren auf mehr als 250 Messungen im Bereich der Laminarströmung und belegen die Existenz einer optimalen Windungskonfiguration.

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References

  1. 1.
    Marner, W. J.; Bergles, A. E.; Chenoweth, J. M.: On the presentation of performance data for enhanced tubes used in shell and tube heat exchangers. ASME Jl. Heat Transfer 105 (1983) 358–364Google Scholar
  2. 2.
    Shenkman, S. M.; Habib, I. S.; Kohler, J. A.: Advances in enhanced surfaces. 23rd ASME Natl. Heat Transfer Conference (1985)Google Scholar
  3. 3.
    Van Rooyen, R. S.; Kroger, D. G.: Laminar flow heat transfer augmentation in internally finned tubes with twisted tape inserts. Proceed. 6th Int. Heat Transfer Conference 2 (1978) 578–581Google Scholar
  4. 4.
    Marner, W. J.; Bergles, A. E.: Augmentation of tube side laminar flow heat transfer by means of twisted tape inserts, Static mixer inserts, internally finned tubes. Proceed. 6th Int. Heat Transfer Conference 2 (1978) 583–588Google Scholar
  5. 5.
    Uttarwar, S. B.; Raja Rao, M.: Augmentation of laminar flow heat transfer in tubes by means of wire coil inserts. ASME Jl. Heat Transfer 107 (1985) 930–935Google Scholar
  6. 6.
    Nag, P. K.; Tolpadi, A. K.: Effect of spiral turbulator on heat transfer in a heat exchanger tube. Indian Jl. Technol. 21 (1983) 206–210Google Scholar
  7. 7.
    Kays, W. M.; London, A. L.: Compact heat exchangers. McGraw-Hill Book CompanyGoogle Scholar
  8. 8.
    Kern, D. Q.: Process Heat Transfer. McGraw-Hill Book CompanyGoogle Scholar

Copyright information

© Springer-Verlag 1994

Authors and Affiliations

  • C. B. Sobhan
    • 1
  • K. T. Mohammed Kutty
    • 1
  • M. Hannan
    • 1
  • P. Krishtaiah
    • 1
  1. 1.Regional Engineering CollegeCalicutIndia

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