LB simulation of heat transfer in flow past a square unit of four isothermal cylinders

Esfahani, Javad Abolfazli; Vasel-Be-Hagh, Ahmadreza

doi:10.1016/j.crme.2012.03.011

Cited by 9 publications

(4 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The governing discrete kinetic equation for internal energy is

{g}_{i}(x+{e}_{i}\unicode{x02206}t,t+\unicode{x02206}t)={g}_{i}(x,t)-\frac{1}{{\tau }_{t}}[{g}_{i}(x,t)-{{g}_{i}}^{\text{eq}}(x,t)].

Here, g i represents the distribution function for internal energy, g i eq indicates the equilibrium internal energy distribution function, e i is discretized (particle) velocity of the lattice in the direction i ( i = 0, …, 8), τ t is relaxation parameter for internal energy that is related to the thermal diffusivity α ( τ t = 3α + 0.5) 27 …”

Section: Computational Details and Problem Descriptionmentioning

confidence: 99%

“…Here, g i represents the distribution function for internal energy, g i eq indicates the equilibrium internal energy distribution function, e i is discretized (particle) velocity of the lattice in the direction i (i = 0, …, 8), τ t is relaxation parameter for internal energy that is related to the thermal diffusivity α (τ t = 3α + 0.5). 27 The local equilibrium density function is calculated by…”

Section: Computational Details and Problem Descriptionmentioning

confidence: 99%

See 1 more Smart Citation

Simulation for flow across heated square cylinders

Patil¹,

Nandgaonkar²,

Sewatkar³

2022

Heat Trans

View full text Add to dashboard Cite

The thermal lattice Boltzmann method is used to examine forced convection heat transfer from six inline heated square cylinders for Re = 100 at 0.5 ≤ s/d ≤ 4.0, where s is the distance between the surfaces of two cylinders and d is the cylinder size. Such a heat transfer is transient in nature for which the present work reports heat transfer regimes such as synchronous, quasiperiodic and chaotic. For 0.5 ≤ s/d ≤ 1.5 the heat transfer is synchronous, for 1.5 ≤ s/d ≤ 3.0 it is quasiperiodic and for 3.0 ≤ s/d ≤ 4.0 it is chaotic in nature at Re = 100. These regimes are confirmed through cylinder Nusselt number signals, its power spectra, and heat wake interference. The appearance of heat transfer regimes for inline heated cylinders is similar to the appearance of flow regimes for inline unheated cylinders except for the fact that transition from synchronous to quasiperiodic regime occurs at s/d = 1.5 for heat transfer and at s/d = 1.1 for flow. The synchronous heat transfer regime is characterized by a single heat wake that envelopes all cylinders while quasiperiodic heat transfer regime is characterized by the formation of thermal blobs in the gap between cylinders. A chaotic heat transfer regime is characterized by the shedding of thermal blobs and interference of thermal blobs by downstream cylinders. Regardless of spacing, the average Nusselt number encountered by cylinders is smaller than that for the

show abstract

“…The governing discrete kinetic equation for internal energy is

{g}_{i}(x+{e}_{i}\unicode{x02206}t,t+\unicode{x02206}t)={g}_{i}(x,t)-\frac{1}{{\tau }_{t}}[{g}_{i}(x,t)-{{g}_{i}}^{\text{eq}}(x,t)].

Section: Computational Details and Problem Descriptionmentioning

confidence: 99%

Section: Computational Details and Problem Descriptionmentioning

confidence: 99%

Simulation for flow across heated square cylinders

Patil¹,

Nandgaonkar²,

Sewatkar³

2022

Heat Trans

View full text Add to dashboard Cite

show abstract

“…Additionally, there are some recent publications on obstacles in an infinite-domain [22][23][24]33,34,11]. Abolfazli Esfahani and Vaselbehagh [5,4] performed a study on the heat transfer around four isothermal cylinders by using Lattice Boltzmann method. They found that the maximum heat transfer is related to the stagnation point of the upstream cylinder.…”

Section: Introductionmentioning

confidence: 99%

The effect of magnetic field on instabilities of heat transfer from an obstacle in a channel

Rashidi

Esfahani

2015

Journal of Magnetism and Magnetic Materials

View full text Add to dashboard Cite

“…Different from the cylindrical object of the above researches, Liu et al [19] focused on the experimental investigation of the flow characteristics for four square cylinders and discussed the effects of the spacing ratio and incidence angle on the flow dynamics at subcritical Reynolds numbers, and found that the interference between four square cylinders varies with the spacing ratio and incidence angle. Several similar experimental tests [20,21] and numerical studies [22][23][24][25] on multiple cylinders also discussed the flow characteristics for pure forced convection. A lot of results fully confirm that the flow characteristics of multiple cylinders strongly depend on the overall arrangement and the attack angle because the incoming flow through differently arranged multiple cylinders structure can change the stability and complexity of the flow fields and enhance the interactions between cylinders.…”

Section: Introductionmentioning

confidence: 99%

An LBM-based investigation of thermal buoyancy and arrangement angle on flow characteristics and heat transfer over four heated square cylinders

Zhang

Xie

Sundén

et al. 2021

Numerical Heat Transfer, Part B: Fundamentals

View full text Add to dashboard Cite

In this work, the effects of thermal buoyancy and rotation angle on the hydrodynamics and mixed convection heat transfer characteristics over four heated identical square cylinders placed in a parallel horizontal channel are numerically studied. For the flow field, the Lattice Boltzmann method (LBM) with multiple relaxation time collision operator (MRT) is implemented and the Bhatnagar-Gross-Ktook collision operator (BGK) is adopted for the thermal field simulation. The distance between two adjacent square cylinders is fixed for a parametric study and a uniform velocity is imposed at the inlet region. Ranges of the influence parameters are defined as: a ¼ 45 , 90 , 120 ; 50 Re 150; 0 Ri 0.5. Several flow and heat transfer parameters including the time-averaged lift/drag coefficients, the global time-averaged Nusselt number and the distributions of local Nusselt number are analyzed, respectively. The vorticity and isotherm patterns are also plotted to illustrate the visual disturbance of the thermal buoyancy and the rotation angle on the flow and thermal fields. Numerical results show that the flow and thermal patterns for all arrangements become disordered and nonsystematic with the introduction of thermal buoyancy, and the thermal pattern for the downstream cylinders has an upward drift in the wake region. The time-averaged lift coefficient for each square cylinder is relatively sensitive to the influence parameters and the arrangement, and it is always less than zero when the Richardson number is not equal to zero. The global timeaveraged Nusselt number is directly proportional to the Reynolds number and Richardson number, and the local Nusselt numbers on the front and rear faces for each square cylinder reach a maximum and minimum, respectively. It is also observed that the distribution of local Nusselt number for all rotation angles is intensively affected by the thermal buoyancy.

show abstract

LB simulation of heat transfer in flow past a square unit of four isothermal cylinders

Cited by 9 publications

References 23 publications

Simulation for flow across heated square cylinders

Simulation for flow across heated square cylinders

The effect of magnetic field on instabilities of heat transfer from an obstacle in a channel

An LBM-based investigation of thermal buoyancy and arrangement angle on flow characteristics and heat transfer over four heated square cylinders

Contact Info

Product

Resources

About