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

Olivier, Jonathan; Meyer, Josua P.

doi:10.1080/10789669.2010.10390916

Cited by 57 publications

(54 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Olivier and Meyer [20] and by Meyer and Olivier [21]. In the laminar flow regime, the same phenomenon is observed as in the turbulent flow regime.…”

Section: The Delayed Transition and The Sharp Transition Is The Resulsupporting

confidence: 59%

“…The properties of the nanofluids, such as the thermal conductivity and viscosity were determined from Equation 2 and 3. The density was determined from [6]: ( 20 ) The specific heat was determined from [19]:…”

Section: Comparison Of Results With Existing Heat Transfer Correlationsmentioning

confidence: 99%

“…The pressure tap diameter was 4 mm, which is less than 10% of the tube diameter. The reason for the small diameter is so that the overall flow is not disturbed since a large hole could lead to a localised eddy forming which results in an error in pressure readings [20,21]. The flow rate was measured using a Coriolis flow meter, which had an accuracy of 0.05% at full scale.…”

Section: Experimental Set-upmentioning

confidence: 99%

“…Thus there is a need for more design information in transitional flow. In the recent works of Meyer and Olivier [20,21,22], the heat transfer coefficients and pressure drops were measured for transitional flow in smooth and enhanced tubes with different types of inlets. They showed that the heat transfer and pressure drop characteristics are stable and that there is a smooth transition from laminar to turbulent flow.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The influence of multi-walled carbon nanotubes on single-phase heat transfer and pressure drop characteristics in the transitional flow regime of smooth tubes

Meyer

McKrell

Grote

2013

International Journal of Heat and Mass Transfer

122

View full text Add to dashboard Cite

In this paper, the convective heat transfer enhancement of aqueous suspensions of multiwalled carbon nanotubes flowing through a straight horizontal tube was investigated experimentally for a Reynolds number range of 1 000 -8 000, which included the transitional flow regime. The tube was made out of copper with an internal diameter of 5.16 mm.Experiments were conducted at a constant heat flux of 13 kW/m 2 with 0.33%, 0.75% and 1.0% volume concentrations of multi-walled carbon nanotubes. The nanotubes had an outside diameter of 10 -20 nm, an inside diameter of 3 -5 nm and a length of 10 -30 µm.Temperature and pressure drop measurements were taken, from which the heat transfer coefficients and friction factors were determined as a function of Reynolds number. It was found that heat transfer was enhanced when comparing the data on a Reynolds-Nusselt graph but when comparing the data at the same velocity, it was shown that heat transfer was not enhanced. Performance evaluation of the nanofluids showed that the increase in viscosity was four times the increase in the thermal conductivity, which resulted in an inefficient nanofluid.

show abstract

“…Olivier and Meyer [20] and by Meyer and Olivier [21]. In the laminar flow regime, the same phenomenon is observed as in the turbulent flow regime.…”

Section: The Delayed Transition and The Sharp Transition Is The Resulsupporting

confidence: 59%

Section: Comparison Of Results With Existing Heat Transfer Correlationsmentioning

confidence: 99%

Section: Experimental Set-upmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The influence of multi-walled carbon nanotubes on single-phase heat transfer and pressure drop characteristics in the transitional flow regime of smooth tubes

Meyer

McKrell

Grote

2013

International Journal of Heat and Mass Transfer

122

View full text Add to dashboard Cite

show abstract

“…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. However, all this work was done on circular tube diameters larger than 5 mm.…”

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

View full text Add to dashboard Cite

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.

show abstract

The effect of high values of relative surface roughness on heat transfer and pressure drop characteristics in the laminar, transitional, quasi-turbulent and turbulent flow regimes

Everts,

Mahomed

2024

Heat Mass Transfer

View full text Add to dashboard Cite

This study investigated the effect of large values of relative surface roughness on the heat transfer and pressure drop characteristics using simultaneously measured heat transfer and pressure drop data. Experiments were conducted using a horizontal circular tube with a base inner diameter of 5 mm and length of 4 m. One smooth and two rough tubes, with relative roughnesses of 0.04 and 0.11, were tested at different constant heat fluxes between Reynolds numbers of 100 and 8 500. Water was used as the test fluid and the Prandtl number varied between 3 and 7. Contrary to the trend in the Moody Chart, a significant increase in laminar friction factors with increasing surface roughness was observed. Both the friction factors and Nusselt numbers as functions of Reynolds number showed a clear upward and leftward shift with increasing surface roughness across the different flow regimes. Furthermore, the boundaries between the flow regimes were the same for the pressure drop and heat transfer results. The width of the transitional flow regime was narrower for rough tubes and had a differing trend. The quasi-turbulent and turbulent flow regimes occurred at lower Reynolds numbers for increasing roughness. When investigating the relationship between heat transfer and pressure drop, it was found that an increase in surface roughness favoured heat transfer in the quasi-turbulent flow regime. This is useful for rough tubes as the quasi-turbulent flow regime onsets early with regards to the Reynolds number in tubes with large roughnesses.

show abstract

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

Abstract: This paper is based on findings resulting from ASHRAE Research Project RP-1280

Cited by 57 publications

References 29 publications

The influence of multi-walled carbon nanotubes on single-phase heat transfer and pressure drop characteristics in the transitional flow regime of smooth tubes

The influence of multi-walled carbon nanotubes on single-phase heat transfer and pressure drop characteristics in the transitional flow regime of smooth tubes

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

The effect of high values of relative surface roughness on heat transfer and pressure drop characteristics in the laminar, transitional, quasi-turbulent and turbulent flow regimes

Contact Info

Product

Resources

About