Abstract This study deals with the analysis of the interacting influences of Lorentz force and bleeding on the hydrothermal behaviors of magnetohydrodynamic (MHD) nanofluid flow and entropy generation in a trapezoidal recess. This trapezoidal recess is created by two inclined steps in a horizontal channel. The Lorentz force is appeared due to the existence of a magnetic field in the flow domain. The Brownian motion influences on the effective characteristics of CuO -water nanofluid are considered to have more accuracy. The effects of bleeding coefficients (−0.005 ≤ Vw ≤ + 0.005), Hartmann number (0 ≤ Ha ≤ 60) and concentration of solid nanoparticles (0 ≤ ϕ ≤ 0.04) on the flow characteristics, heat transfer and flow irreversibility rates are investigated. The results show that the trends and values of friction coefficient, Nusselt number and entropy generation number can be different at the various magnitudes of Ha and Vw, whereas the ϕ parameter only increases the values of them. These differences are related to the variations of streamlines contours against the Ha, Vw and ϕ parameters.

中文翻译：

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利用热力学第二定律分析洛伦兹力和出血对梯形凹槽中纳米流体流动的水热行为的相互作用影响

摘要 本研究分析了洛伦兹力和出血对磁流体动力学 (MHD) 纳米流体在梯形凹槽中流动和熵产生的水热行为的相互作用影响。这个梯形凹槽是由水平通道中的两个倾斜台阶形成的。洛伦兹力的出现是由于流域中存在磁场。布朗运动对CuO-水纳米流体有效特性的影响被认为具有更高的准确性。研究了渗出系数 (-0.005 ≤ Vw ≤ + 0.005)、哈特曼数 (0 ≤ Ha ≤ 60) 和固体纳米粒子浓度 (0 ≤ φ ≤ 0.04) 对流动特性、传热和流动不可逆率的影响。结果表明，摩擦系数的趋势和值，Nusselt 数和熵生成数在 Ha 和 Vw 的不同幅度下可能不同，而 ϕ 参数只会增加它们的值。这些差异与流线轮廓相对于 Ha、Vw 和 ϕ 参数的变化有关。