  Citation: Agarwal, V.; Singh, B.; Kumari, A.; Jamshed, W.; Nisar, K.S.; Almaliki, A.H.; Zahran, H.Y. Steady Magnetohydrodynamic Micropolar Fluid Flow and Heat and Mass Transfer in Permeable Channel with Thermal Radiation. Coatings 2022, 12, 11. https://doi.org/10.3390/ coatings12010011 Academic Editor: Rahmat Ellahi Received: 20 November 2021 Accepted: 15 December 2021 Published: 23 December 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). coatings Article Steady Magnetohydrodynamic Micropolar Fluid Flow and Heat and Mass Transfer in Permeable Channel with Thermal Radiation Vandana Agarwal 1 , Bhupander Singh 2 , Amrita Kumari 3 , Wasim Jamshed 4 , Kottakkaran Sooppy Nisar 5, * , Abdulrazak H. Almaliki 6 and H. Y. Zahran 7,8 1 Department of Computer Application, Raghunath Girl’s (PG) College, Meeru 250001, India; vandanargmeerut@gmail.com 2 Department of Mathematics, Meerut College, Meerut 250003, India; bhupandersingh1969@yahoo.com 3 Department of Mathematics, AS(PG) College Mawana, Meerut 250001, India; ampanwar@gmail.com 4 Department of Mathematics, Capital University of Science and Technology (CUST), Islamabad 44000, Pakistan; wasiktk@hotmail.com 5 Department of Mathematics, College of Arts and Sciences, Prince Sattam bin Abdulaziz University, Wadi Aldawaser 11991, Saudi Arabia 6 Department of Civil Engineering, College of Engineering, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia; a.almaliki@tu.edu.sa 7 Laboratory of Nano-Smart Materials for Science and Technology (LNSMST), Department of Physics, Faculty of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia; heldemardash@kku.edu.sa 8 Nanoscience Laboratory for Environmental and Biomedical Applications (NLEBA), Metallurgical Lab. 1, Department of Physics, Faculty of Education, Ain Shams University, Roxy, Cairo 11757, Egypt * Correspondence: n.sooppy@psau.edu.sa Abstract: The present work is devoted to the study of magnetohydrodynamic micropolar fluid flow in a permeable channel with thermal radiation. The Rosseland approximation for thermal radiation is taken into account in the modelling of heat transfer. The governing equations are expressed in non-dimensional form. The Homotopy Perturbation Method (HPM) is briefly introduced and applied to derive the solution of nonlinear equations. The effects of various involved parameters like Reynolds number, microrotation parameter and Prandtl number on flow and heat transfer are discussed. Further, their effects on Nusselt and Sherwood numbers are also investigated from the physical point of view. Analytic solutions of the problem are obtained by HPM and a numerical technique bvp4c package MATLAB is applied to predict the graphs between different parameters. Keywords: micropolar fluid; permeable channel; homotopy perturbation method; heat transfer; magnetohydrodynamic; thermal radiation 1. Introduction From the industrial point of view, the process of heat and mass transfer has a great im- pact. Many researchers concentrate on this area. In particular, in the metallurgical industry, an application of heat transfer criterion has been studied with magnetohydrodynamic mi- cropolar fluid flows. Mohamed and Abo-Dahab [1], Perdikis and Raptis [2] and Raptis [3] discussed the impact of heat and mass transfer in micropolar and magnetohydrodynamic micropolar fluid flows in the presence of various characteristics like thermal radiation, heat generation, and porous media. Seddeek et al. [4] obtained the analytic solution of the problem leading to the effect of radiation on the flow of a magneto-micropolar fluid past a continuously moving plate with suction and blowing. El-Arabawy [5] observed the behaviour of suction and injection in his problem. On the other hand, Sharma and Gupta [6] studied the effects of porosity and thermal convection on micropolar fluids. The numerical simulation of the solution of micropolar fluid flows with suction and injection has been discussed by Subhadra et al. [7], Takhar et al. [8], Kelson and Farrell [9], and Muhammad et al. [10]. A few years ago, the flows in permeable channels and circular pipes made a considerable impact, drawing attention to these researchers. Coatings 2022, 12, 11. https://doi.org/10.3390/coatings12010011 https://www.mdpi.com/journal/coatings