Effect of tube spacing, fin density and Reynolds number on overall heat transfer rate for in-line configuration

Tahseen, Tahseen Ahmad; Rahman, M. M.; Ishak, M.

doi:10.15282/ijame.12.2015.20.0255

Cited by 5 publications

(3 citation statements)

References 27 publications

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“…Compact HE has been widely used in many industrial applications due to its compactness, low weight, high competence and low cost. It includes two sorts of HE either fin-and-tube or plate-and-fin [4][5][6][7][8]. Fin and tube HE, in particular, has been used in engineering fields such as chemical engineering, petrochemical, heating ventilation and air conditioning, compressors, and fan coils.…”

Section: Introductionmentioning

confidence: 99%

Investigation of thermal-hydraulic performance in flat tube heat exchangers at various tube inclination angles

Adam¹,

Oumer²,

Alias³

et al. 2022

Int. J. Automot. Mech. Eng.

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The performance of compact fin-and-flat tube heat exchangers (HE) can be affected by many geometrical and processing factors and one of them is tube inclination angle. However, the effect of flat tube inclination angle on the thermal-hydraulic performance of the HE is not fully examined. This paper investigates the effects of flat tube inclination angles on heat transfer and pressure drop characteristics of fined flat tube HE when the tubes are deployed in in-line and staggered arrangements. A symmetric numerical method based on FLUENT software was carried out with six different tube inclination angles (0°, 30°, 60°, 90°, 120°, and 150°) in moderately high Reynolds number. From the results, it was observed that heat transfer coefficient increased with the augmentation of the tube inclination angle from 0 o to 90 o and decreased for 120 o and 150 o . With the increase of tube inclination angle, the average Nusselt number rose by 36.3%. This might be due to the reason that the tube surface area increases with the inclination angle, which also results in the largest increment of the pressure drop by 42.0%. Overall, the 90 o tube inclination angle showed the highest enhancement in heat transfer for both inline and staggered configurations with a maximum enhancement of 41.2% for in-line and 32.2% for staggered arrangements. However, the heat transfer enhancements were accompanied by high-pressure drop penalties of up to 44.2% and 42.6% for in-line and staggered arrangements, respectively. Therefore, inclining the tubes at 90 o is recommended where high heat transfer is required. On the other hand, 0 o tube inclination angle is recommended where pumping power is a crucial issue.

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Section: Introductionmentioning

confidence: 99%

Investigation of thermal-hydraulic performance in flat tube heat exchangers at various tube inclination angles

Adam¹,

Oumer²,

Alias³

et al. 2022

Int. J. Automot. Mech. Eng.

Self Cite

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“…For flow through an urban area under neutral conditions and without pollutant dispersion, the only forces of concern are the inertia and viscous forces which are included in the Reynolds number (Re). For example, in a tube heat exchanger, the pumping power decreases and the heat transfer enhances as the Reynolds number increases [12]. The problem with wind tunnel experiments is that the model has to be scaled-down by two or three orders of magnitude which requires a corresponding increase in flow speed to hold the dynamic similarity between the model and its prototype.…”

Section: Introductionmentioning

confidence: 99%

Large eddy simulation of wind flow through an urban environment in its full-scale wind tunnel models

Reda

Zulkifli²,

Harun³

2017

J. MECH. ENG. SCI.

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Wind flow through urban areas is studied either by wind tunnel scale experiments or via computational fluid dynamics simulations through full-scale actual models. The large difference between the Reynolds numbers based on the geometries of actual cities and wind tunnel scale cities makes the dynamic similarity between the two models uncertain. In this study, the mean and turbulent flow parameters were investigated using a large eddy simulation for two models i.e. the actual urban area model and the wind tunnel scale (1:1000) model. Kuala Lumpur City Centre, Malaysia, was considered as the case study of an urban area. Vertical velocity profiles were plotted at five locations representing different building packing densities. The results of wind tunnel scale model largely agreed with the actual model with some discrepancies in the building vicinity and wakes. The dissimilarity of the wake patterns due to the large difference in Re was responsible for the deviations. Largest discrepancies were found in the lateral and wall-normal velocity components and turbulence stresses. The results casted a shadow on the applicability of the conclusions derived from the simulations on wind tunnel scale models to the actual urban environments they represented. The deviation between the two models should be assessed before proceeding with experimental or numerical simulations on small-sized models.

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“…Poor ventilation often leads to temperature rise, pollutant concentration, and high loads on air conditioning systems, which in turn causes more pollutant emission and further temperature increase. Along with the persisting attempts to reduce the heat release from burning fossil fuels either by improving the efficiency of industrial equipment [1] or developing clean energy sources [2], scientific research targets planning modern cities of enhanced natural ventilation potentials and minimal solar absorption [3]. In addition to natural ventilation, the study of atmospheric flow through cities is important to evaluate the stresses [4] and vortex-induced vibrations [5] on buildings and structures due to turbulence coherent structures [6].…”

Section: Introductionmentioning

confidence: 99%

Towards developing an idealised city model with realistic aerodynamic features

Reda

Zulkifli²,

Harun³

2017

J. MECH. ENG. SCI.

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Many concerns related to natural ventilation in urban areas have been deduced from experimental or computational fluid dynamics simulations on idealised models. However, it is not definite that the flow through these idealised models presents similar characteristics to actual urban areas. The objective of this research is to suggest an approach to close the gap between idealised models and genuine cities; i.e., predict actual urban flow characteristics from the ready data of idealised models. The flow was simulated by large-eddy simulation through both the actual city model and a group of idealised models of different structures but the same average dimensions and buildingpacking-density as the actual city. The numerical setup was validated by comparison with wind tunnel measurements from the literature. It was found that an equivalent to the average velocity profile throughout an idealised model can be achieved by a mix of the "five-point spatial average" and the "four-point spatial average". The vertical profiles of mean and turbulent windward velocities of the idealised models manifest a general similarity to those of the actual model. On the other hand, the cross-wind and wall-normal components show large discrepancies. In all cases, the idealised models exhibit very narrow atmospheric surface layer heights compared to the actual model. IM-RAN (which represents a structure of semi-random configuration) displayed the closest results to the actual model but condensed in half the actual model surface layer height. A correction formula was devised to close the gap between the two models. The results confirm the ability to utilise idealised models to deliver recommendations regarding urban environment planning; though, attention should be paid to the selection of the idealised model and corrections may be needed.

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Effect of tube spacing, fin density and Reynolds number on overall heat transfer rate for in-line configuration

Cited by 5 publications

References 27 publications

Investigation of thermal-hydraulic performance in flat tube heat exchangers at various tube inclination angles

Investigation of thermal-hydraulic performance in flat tube heat exchangers at various tube inclination angles

Large eddy simulation of wind flow through an urban environment in its full-scale wind tunnel models

Towards developing an idealised city model with realistic aerodynamic features

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