• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.4
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• pp.423-430
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• 1998

Single phase heat transfer coefficients were measured for turbulent water flow in a micro-fin tube by using Wilson plot technique. An experiment for counterflow heat exchange between the micro-fin tube and its outer annulus passage was performed. The annulus side heat transfer resistance was varied and the overall heat transfer coefficients were measured. The single-phase heat transfer coefficients in a micro-fin tube were obtained by Wilson plot technique. Nusselt numbers based on the real heat transfer area and the nominal area were about 35% and 50% larger than those for smooth tube respectively Also, single-phase heat transfer correlations based on real heat transfer area and nominal area have been proposed for a micro-fin tube.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.270-275
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• 2000

In this study, heat transfer and Pressure drop characteristics for R-718 in the plate and shell heat exchanger (P&SHE) investigated experimentally. The plates are circular and welded into a stack which fits into a cylindrical shell in P&SHE. Although apparently very different from rectangular the compact brazed plate heat exchanger (CBE), the underlying flow passage structure through the P&SHE is the same as in the CBE. The R-718 between plate side and shell side was performed a counterflow heat exchange. Heat transfer characteristic of R-718 were measured for turbulent flow in P&SHE by using wilson plot technique. Heat transfer experiment Ivas performed in the $200{\leq}Re{\leq}500$ regime and Pressure drop experiment was performed in the $150{\leq}Re{\leq}1600$ regime. The purpose of this study is to investigate heat transfer and friction factor correlations for R-718 in P&SHE and to offer fundamental data for experiment

• Journal of the Korean Solar Energy Society
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• v.26 no.4
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• pp.93-100
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• 2006

An experimental study of a counterflow heat exchanger was performed. The heat exchanger had an effective heat transfer length of 1000mm and was operated in a counterflow arrangement with hot water($30{\pm}0.5^{\circ}C$, $Re_i=3500{\sim}20000$) in the inner tube(copper tube, $d_0=9.52mm$) and cold water($15{\pm}0.5^{\circ}C$, $Re_{DH}=10700{\sim}39000$) in the annulus(copper tube, $D_0=19.05mm$). Overall heat transfer coefficients were calculated and heat transfer coefficients in the inner tube and the annulus were determined using Wilson plots. The inner Nusselt number was compared with that of Gnielinski's correlation and they agreed within ${\pm}10%$ error. The trends were typical for a fluid-to-fluid heat exchanger with the overall heat transfer coefficient increasing with both inner and annulus flow rates. In the range of this experiment, Nusselt numbers for the inner tube flow were almost identical with those of the annulus flow at the same Reynolds number.