A New Method to Specify the Outlet Boundary Condition of Fluid Flow in the Channel Formed by Tube Bank Fins

Lin, Zhihong; Wang, Liang-Bi; Gao, Quanfu

doi:10.1615/computthermalscien.2011003273

Cited by 11 publications

(4 citation statements)

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“…For the developing flow in the tube bank fins passage, the outlet velocity boundary condition is very difficult to specify because a recirculation flow may be encountered at the physically realistic outlet boundary. As reported in reference [25], the outlet boundary would be divided into two parts according to whether the recirculation flow exists at outlet boundary or not, then boundary conditions at the outlet cross section (i.e., GHH 0 G 0 , see Figure 4b) are prescribed as follows.…”

Section: Multi-domain Coupled Numerical Methods For Heat Exchangermentioning

confidence: 99%

A Multi-Domain Coupled Numerical Method for a Flat Tube Bank Fin Heat Exchanger with Delta-Winglet Vortex Generators

Lin

Wang

2014

Numerical Heat Transfer, Part A: Applications

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Along with the improvement of numerical methods and the development of computer power, using a numerical method to design a tube bank fin heat exchanger becomes increasingly possible. In real working conditions, the conjugate heat transfer process arises in this type of exchanger. To provide a feasible numerical model and its relevant method to properly assess the thermal performance of exchanger, in this article, a multi-domain coupled numerical method is presented, in which the conduction in solid regions and the convection in flow regions are calculated together with a fully coupled manner. The reliability of a numerical method was tested through comparing average numerical results with experimental results of a real heat exchanger. The results reveal that the multi-domain coupled numerical method can achieve more accurate positions of the interfaces, arrange the orthogonal grids close to the interfaces, and use more reasonable criteria of convergence. Thus, we have achieved reasonable results that agree with the experimental data of the real heat exchanger under the working condition within 10% deviation in the Reynolds number region studied, and got overall heat transfer coefficient of a flat tube bank fin heat exchanger.

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Section: Multi-domain Coupled Numerical Methods For Heat Exchangermentioning

confidence: 99%

A Multi-Domain Coupled Numerical Method for a Flat Tube Bank Fin Heat Exchanger with Delta-Winglet Vortex Generators

Lin

Wang

2014

Numerical Heat Transfer, Part A: Applications

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“…3(a). At the inlet, the bulk velocity is set to be u in , the velocities in y and z direction are equal to zero, and the bulk temperature is set to be T in , while at the outlet, the method proposed in [25] is adopted, for the details see Refs. [16,[19][20][21]25].…”

Section: Geometric Descriptionmentioning

confidence: 99%

“…At the inlet, the bulk velocity is set to be u in , the velocities in y and z direction are equal to zero, and the bulk temperature is set to be T in , while at the outlet, the method proposed in [25] is adopted, for the details see Refs. [16,[19][20][21]25]. On the two lateral sides of the simulation region, the symmetry boundary conditions are used for flow region; while for tube walls, the non-slipping condition for velocity and uniform temperature are used.…”

Section: Geometric Descriptionmentioning

confidence: 99%

Heat transfer augmentation characteristics of a fin punched with curve trapezoidal vortex generators at the rear of tubes

Lin

Hanzo

et al. 2022

THERM SCI

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The thermal-hydraulic characteristics of a novel fin punched with curve trapezoidal vortex generators (CTVGs) are investigated numerically. The effects of multi-parameters including the geometry of CTVG, the location of CTVGs, and working condition on thermal performance are considered. On one hand, CTVGs can availably lessen the size of tube wake zone, decrease the mechanical energy consumption and heighten the fin heat transfer ability in this area. On the other hand, the secondary flow strength is strengthened because the longitudinal vortices generated by CTVGs, which efficiently enhances the heat transfer on the fin downstream CTVGs. Close relationship exists between the volume-averaged secondary flow strength and the mean Nusselt number. For studied cases, the optimal circumferential location angle of ? = 90? is found, while the optimal radial location Dg is about 1.8 times the tube outside diameter. The smaller is the height or base length of CTVGs, the better the thermal performance of the enhanced fin punched with CTVGs. Better thermal performance is achieved as the fin spacing is about 0.24 times the tube outside diameter.

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“…2b), a recirculation flow may be encountered, the proposed treatment for this kind outlet boundary is adopted [28]. The outlet boundary is divided into two parts according to whether the recirculation flow exists or not.…”

Section: Physical Model and Mathematic Formulationsmentioning

confidence: 99%

The optimum fin spacing of circular tube bank fin heat exchanger with vortex generators

Wang

et al. 2013

Heat Mass Transfer

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In real application, once the pattern of fin is determined, fin spacing of tube bank fin heat exchanger can be adjusted in a small region, and air flow velocity in the front of the heat exchanger is not all the same. Therefore, the effects of fin spacing on heat transfer performance of such heat exchanger are needed. This paper numerically studied the optimal fin spacing regarding the different front flow velocities of a circular tube bank fin heat exchanger with vortex generators. To screen the optimal fin spacing, an appropriate evaluation criterion JF was used. The results show that when front velocity is 1.75 m/s, the optimal fin spacing is 2.25 mm, when front velocity is 2.5 m/s, the optimal fin spacing is 2 mm, and when front velocity is higher than 2.5 m/s, the optimal fin spacing is 1.75 mm. List of symbolsA Cross section area of flow passage (m 2 ) A front Cross section area of flow passage at front inlet (m 2 ) c p Specific heat capacity (J/kg K) D Diameter of the tube (m) d e Characteristic length of flow channel (m) F Total surface involved in heat transfer in the computational domain (m 2 ) f Friction factor, f = Dpd e /(L x qu max 2 /2) h Convective heat transfer coefficient (W/m 2 K) H Height of winglet type vortex generator (m) J n ABS Absolute vorticity flux along the normal direction of cross section (1/s) J n ABS;S Cross section average absolute vorticity flux (1/s) J n ABS;V Volume average absolute vorticity flux (1/s) L Base length of vortex generator (m) L x Stream wise length of fin (m) n Direction normal to the cross section or wall surface N 2 Number of the tubes Nu Nusselt number, Nu = hd e /k p Pressure (Pa) Re Reynolds number, Re = qu max d e /l S 1 Transversal pitch between the tubes (m) S 2 Longitudinal pitch between the tubes (m) T p Net fin spacing (m) T Temperature (K) u front Velocity of air at front inlet (m/s) u in Velocity of air at fin passage inlet (m/s) u max Maximum average velocity of air (m/s) u i , u, v, w Components of velocity vector (m/s) x, y, z CoordinatesGreek variables k Thermal conductivity (W/m K) lViscosity (kg/m s) qDensity (kg/m 3 )

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A New Method to Specify the Outlet Boundary Condition of Fluid Flow in the Channel Formed by Tube Bank Fins

Cited by 11 publications

References 0 publications

A Multi-Domain Coupled Numerical Method for a Flat Tube Bank Fin Heat Exchanger with Delta-Winglet Vortex Generators

A Multi-Domain Coupled Numerical Method for a Flat Tube Bank Fin Heat Exchanger with Delta-Winglet Vortex Generators

Heat transfer augmentation characteristics of a fin punched with curve trapezoidal vortex generators at the rear of tubes

The optimum fin spacing of circular tube bank fin heat exchanger with vortex generators

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