Transitional Heat Transfer in Plain Horizontal Tubes

Tam, Lap Mou; Ghajar, Afshin J.

doi:10.1080/01457630600559538

Cited by 85 publications

(37 citation statements)

References 8 publications

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“…However, there was good agreement for the higher Nusselt number values, where the flow was turbulent. This is understandable since Tam and Ghajar's (2006) correlation in this region is a variant of the Sieder and Tate (1936) correlation, which was in excellent agreement with the experimental data.…”

Section: Correlationsupporting

confidence: 80%

“…Prior to developing a correlation, a comparison will be made to the correlations developed by Tam and Ghajar (2006) for heat transfer for the different inlets. This comparison for all the inlets is shown in Figure 16.…”

Section: Correlationmentioning

confidence: 99%

“…This, however, is not due to the correlation, but rather the difference in fluids. Tam and Ghajar's (2006) correlation was developed for a fluid with a Prandtl number ranging from 40 to 160 for the laminar and transition regions. Further, it was developed for a fluid being heated with a wall-to-bulk viscosity ratio ranging from 1.2 to 3.8 for the same regions.…”

Section: Correlationmentioning

confidence: 99%

See 2 more Smart Citations

Single-Phase Heat Transfer and Pressure Drop of the Cooling of Water inside Smooth Tubes for Transitional Flow with Different Inlet Geometries (RP-1280)

Olivier¹,

Meyer

2010

HVAC&R Research

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Section: Correlationsupporting

confidence: 80%

Section: Correlationmentioning

confidence: 99%

Section: Correlationmentioning

confidence: 99%

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Single-Phase Heat Transfer and Pressure Drop of the Cooling of Water inside Smooth Tubes for Transitional Flow with Different Inlet Geometries (RP-1280)

Olivier¹,

Meyer

2010

HVAC&R Research

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“…Nusselt number transition also stabilized at approximately Re = 2 300, similar to the sudden contraction inlet. Nusselt numbers for Reynolds numbers above 2 300 The results of this study are different than those of the work done by Meyer and co-authors [31][32][33] and Ghajar and co-authors [25][26][27][28][29][30]. In these studies for larger scaled channels the bellmouth inlet type delayed the onset of transition and in contrary, the laminar regime was shortened by the presence of the bellmouth inlet type.…”

Section: Bellmouth Inlet Resultscontrasting

confidence: 55%

“…The influence of the inlet on transition has been investigated systematically by the laboratories of Ghajar at Oklohoma state University and Meyer at the University of Pretoria. Ghajar and co-authors [25][26][27][28][29][30] investigated the influence of different types of inlets while using a constant heat flux. Meyer and co-authors used a constant wall temperature and investigated smooth [31] and enhanced tubes [32,33] and also investigated the use of nanofluids [34] during constant heat flux conditions.…”

Section: Introductionmentioning

confidence: 99%

Inlet flow effects in micro-channels in the laminar and transitional regimes on single-phase heat transfer coefficients and friction factors

Dirker

Meyer

Garach

2014

International Journal of Heat and Mass Transfer

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An experimental investigation of heat transfer and pressure drop in rectangular micro-channels was conducted for water in the laminar and transitional regimes for three different inlet configurations.The inlet types under consideration were the sudden contraction, bellmouth, and swirl inlet types, and hydraulic diameters of 0.57 mm, 0.85 mm, and 1.05 mm were covered. It was found that the critical Reynolds number and the transitional behaviour in terms of heat transfer coefficients and friction factors were influences significantly by the inlet type. For the sudden contraction inlet type, which were investigated for both adiabatic, as well as diabatic cases, adiabatic friction factors were predicted well by the laminar Shah and London correlation, while diabatic friction factors were decreased with an increase in wall heat flux. The sudden contraction inlet critical Reynolds numbers were found to be between 1 800 and 2 000 for adiabatic cases, while for diabatic cases the transition regime commenced at a Reynolds number of about 2 000. The bellmouth and swirl inlet types were investigated for diabatic cases only with swirl inlet tests limited to the 1.05 mm channel. Laminar 2 friction factors were approximately similar to those of the sudden contraction inlet type, however, after the commencement of transition both inlet types exhibited higher friction factors than the sudden contraction inlet. Minor transition occurred as early as at Reynolds numbers of 1 200 and 800 for the bellmouth and swirl inlet types respectively while major transition occurred at Reynolds numbers of approximately 1 800 and 1 500 respectively. Critical Reynolds numbers were found not be significantly influenced by the channel to diameter to length ratio considered in this study. Laminar Nusselt numbers were predicted well by conventional macro-channel thermal entry correlations. The swirl inlet type exhibited the highest friction factors and Nusselt numbers in the transitional regime followed by the bellmouth inlet type. During transition while compared with the sudden contraction inlet, both the bellmouth and swirl inlet types exhibited larger enhancement in heat transfer than increases in the friction factor penalty. Based on the experimental data obtained in this study, a set of correlations were developed which describes the relation between the friction factor and Colburn jfactor. Depending on the inlet type, the correlations predicted between 94% and 100% of the results to within 10% of the experimental measurements.

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Turbulent Internal Flow: Momentum and Heat Transfer

2023

Introduction to Convective Heat Transfer

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Transitional Heat Transfer in Plain Horizontal Tubes

Cited by 85 publications

References 8 publications

Single-Phase Heat Transfer and Pressure Drop of the Cooling of Water inside Smooth Tubes for Transitional Flow with Different Inlet Geometries (RP-1280)

Single-Phase Heat Transfer and Pressure Drop of the Cooling of Water inside Smooth Tubes for Transitional Flow with Different Inlet Geometries (RP-1280)

Inlet flow effects in micro-channels in the laminar and transitional regimes on single-phase heat transfer coefficients and friction factors

Turbulent Internal Flow: Momentum and Heat Transfer

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