Heat transfer analysis of plain and dimpled tubes with different spacings

Afzal, Asif; A.D, Mohammed Samee; Javad, Abdul; S, Ahamed Shafvan; Ajinas, P; M, Ahammedul Kabeer K.

doi:10.1002/htj.21318

Cited by 42 publications

(19 citation statements)

References 29 publications

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“…Three various meshes are created for the flow domain in the pipe. [20][21][22] The results showed that the Nu number lower than 1.21% when the mesh number variations from 501,245 elements up to 3501683 elements. So, mesh 3,506,485 was selected for this investigation.…”

Section: Generation Of Mesh Domain and Grid-independent Studymentioning

confidence: 97%

Flow felid and heat transfer enhancement investigations by using a combination of corrugated tubes with a twisted tape within 3D circular tube based on different dimple configurations

2021

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Different dimple geometrical configurations with a combination of corrugated tubes and twisted tape are numerically investigated. Water is used as a working fluid for constant heat flux heat transfer conditions at the pipe wall. The dimensionless diameter of the dimples (d/D) used in this study is 0.09, 0.18, 0.27, and 0.36. However, the corrugation configuration diameter is 1 mm. The numerical simulations are carried out at the Reynolds number in the range of 1500-14,000. The outcomes reveal that the friction factor (f) and Nu number are augmented as the dimple diameter increases. The Nu number ratio of 1.25 is found for a dimple pipe tube with a diameter of 4 mm. The numerical outcome presented more mixing, secondary, and vortex produced in the main flow direction and near the pipe wall to the rotating flow induced by twisted tape. Moreover, mixed, secondary vortices and rotational flow originate behind and near the dimple, twisted tape, and corrugation surfaces. These rotational and vortices can promote mixing in flow between the thermal boundary layer and velocity boundary flow layer. So, increase the heat transfer enhancement. The improved pipes with different dimple diameters produce a maximum performance evaluation factor of is more than 1.25. K E Y W O R D S corrugated pipe, dimple configurations, evaluation of thermal performance, heat transfer, twisted tape How to cite this article: Al-Obaidi AR, Alhamid J, Hamad F. Flow felid and heat transfer enhancement investigations by using a combination of corrugated tubes with a twisted tape within 3D circular tube based on different dimple configurations.

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Section: Generation Of Mesh Domain and Grid-independent Studymentioning

confidence: 97%

Flow felid and heat transfer enhancement investigations by using a combination of corrugated tubes with a twisted tape within 3D circular tube based on different dimple configurations

2021

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“…To measure the thermophysical properties of MWCNT-W nanofluid the following Equations 2-5 were used. Density, dynamic viscosity, specific heat capacity and thermal conductivity required to calculate the various thermal performance parameters of MWCNT-W nanofluid these equations were used [23][24][25][26][27][28][29][30][31].…”

Section: Measurement Of Thermo Physical Propertiesmentioning

confidence: 99%

Comparative thermal performance analysis of water, engine coolant oil and MWCNT-W nanofluid in a radiator

Afzal¹,

Samee²,

Razak³

2018

MMC_B

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A comparative experimental investigation for thermal performance analysis of three different coolants flowing in a radiator is presented. Water (W) is used as base fluid for 0.01% volume concentration Multi Walled Carbon Nano Tube (MWCNT) nanoparticle. One step method is used to prepare the MWCNT-Water nanofluid. Cross flow unmixed radiator type heat exchanger is considered for the analysis. Performance of radiator subjected to flow of coolants like MWCNT-W nanofluid, and engine coolant oil are compared with water as coolant. Thermal analysis is conducted for different flow rates of 0.25 lpm (liter per minute), 0.5 lpm and 0.75 lpm. For 0.25, 0.5 and 0.75 lpm flow rate, variation in friction factor, heat transfer coefficient, Nu (Nusselt number), pressure drop and pumping power of these coolants is compared. Among the coolants considered MWCNT-W nanofluid comparatively gives maximum heat transfer enhancement due to its high heat carrying capacity. However MWCNT-W nanofluid consumes more pumping power than the other two coolants due its increased viscosity and pressure drop.

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“…It was pointed out that critical Reynolds numbers are transited down to 1400 with the acceleration of roughness, and heat transfer enhancement can be raised to 30%. Afzal et al 13 reported heat transfer enhancement of plain and dimpled tubes with different spacings by an experimental study. The analysis showed that spacing plays an important role in affecting the surface temperature and heat transfer coefficient.…”

Section: Introductionmentioning

confidence: 99%

Effect of outline curvature degree on heat transfer and flow characteristics inside dimpled tubes and spirally grooved tubes

2021

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The flow behaviors and heat transfer characteristics have been studied inside the dimpled tubes and spirally grooved tubes with different curvature degrees, which is considered for the first time within the influence factors. A three‐dimensional numerical simulation by periodic boundary conditions is performed to model the fully developed flow of dimpled and grooved sections to acquire the finer mesh and more accurate results. In addition, the dimple and groove outlines with different curvature degrees are generated by polynomial functions. Effects of curvature degrees for dimpled tubes and spirally grooved tubes on flow, heat transfer, and comprehensive performances are discussed. The results indicate that the influence of curvature degrees for dimpled tubes exhibit an opposite behavior when compared with those for spirally grooved tubes. On the whole, all performance factors increase with the growing curvature degree for dimpled tubes but decrease with the increasing curvature degree for spirally grooved tubes. By comparing different curvature degrees, the maximum ranges of heat transfer enhancement are 1.50–2.22 and 2.54–2.82, respectively, for dimpled and grooved tubes with respect to Re. Thermal and hydraulic fields are considered to analyze the mechanism of heat transfer enhancement. The analysis shows that the way the dimple changes thermohydraulic properties differs from the way the groove changes the properties.

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Heat transfer analysis of plain and dimpled tubes with different spacings

Cited by 42 publications

References 29 publications

Flow felid and heat transfer enhancement investigations by using a combination of corrugated tubes with a twisted tape within 3D circular tube based on different dimple configurations

Flow felid and heat transfer enhancement investigations by using a combination of corrugated tubes with a twisted tape within 3D circular tube based on different dimple configurations

Comparative thermal performance analysis of water, engine coolant oil and MWCNT-W nanofluid in a radiator

Effect of outline curvature degree on heat transfer and flow characteristics inside dimpled tubes and spirally grooved tubes

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