Purpose

The purpose of this paper is to study the unsteady ferrofluid flow with a hot source helix inside a cavity under the impacts of a variable magnetic field by using the incompressible smoothed particle hydrodynamics method.

Design/methodology/approach

The governing equations are formulated by considering the basics of the magnetohydrodynamic and ferrohydrodynamics. Different locations of a variable magnetic source outside the geometry are investigated. The helical coils are extensively applied in the cooling and heating of air conditioners and heat pumps. Computations were carried out for different lengths of the heated helix (0.2 ≤ L_h ≤ 0.8), different locations of the magnetic source, (a = 0.5, b = −0.01), (a = 0.5, b = 1.01), (a = 1.01, b = 0.5), (a = −0.01, b = 0.5), different numbers of the inner helix (one helix, two helixes and three helixes) and different values of the nanoparticles volume fraction (0% ≤ ϕ ≤ 10%).

Findings

The outcomes of the investigations revealed that an increase in the lengths of a helix by 0.4 results in a reduction of the stream function by 25.60%. In addition, when the magnetic wire is located near the center of the right wall, the maximum values of the average Nusselt number are obtained while the smallest values of the average Nusselt number are given when the magnetic source is located near center of the top wall.

Originality/value

The novelty of this paper is investigating the natural convection flow from two different models of an inner hot helix inside a cavity with considering different locations of variable magnetic sources.

中文翻译：

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可变磁场对包含螺旋的空腔内铁磁流体流动的影响使用 ISPH 方法

目的

本文的目的是利用不可压缩光滑粒子流体动力学方法研究变磁场作用下空腔内具有热源螺旋的非定常铁磁流体流动。

设计/方法/方法

控制方程是通过考虑磁流体力学和铁流体力学的基础来制定的。研究了几何形状外可变磁源的不同位置。螺旋盘管广泛应用于空调和热泵的制冷和制热。对不同长度的加热螺旋 (0.2 ≤ L _h ≤ 0.8)、不同位置的磁源进行计算，( a = 0.5, b = -0.01), ( a = 0.5, b = 1.01), ( a = 1.01, b = 0.5), ( a = −0.01, b = 0.5)、不同数量的内螺旋（一个螺旋、两个螺旋和三个螺旋）和不同的纳米颗粒体积分数值（0% ≤ φ ≤ 10%）。

发现

调查结果显示，螺旋长度增加 0.4 会导致流函数减少 25.60%。此外，当磁线位于右壁中心附近时，得到平均努塞尔数的最大值，而当磁源位于顶壁中心附近时，平均努塞尔数得到最小值.

原创性/价值

本文的新颖之处在于研究了来自空腔内内部热螺旋的两种不同模型的自然对流，同时考虑了可变磁源的不同位置。