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PurposeTo highlight the effect of viscous and Joule heating on different ionized gases in the presence of magneto and thermal radiation effects.Design/methodology/approachThe conservation equations are written for the MHD forced convection in the presence of thermal radiation. The governing equations are transformed into non‐similar form using a set of dimensionless variables and then solved numerically using Keller box method.FindingsThe increasing of fluid suction parameter enhances local Nusselt numbers, while the increasing of injection parameter decreases local Nusselt numbers. The inclusion of thermal radiation increases the heat transfer rate for both ionized gases suction or injection. The presence of magnetic field decreases the heat transfer rate for the suction case and increases it for the injection case. Finally, the heat transfer rate is decreased due to viscous dissipation.Research limitations/implicationsThe combined effects of both viscous and Joule heating on the forced convection heat transfer of ionized gases for constant surface heat flux surfaces can be investigated.Practical implicationsA very useful source of coefficient of heat transfer values for engineers planning to transfer heat by using ionized gases.Originality/valueThe viscous and Joule heating of ionized gases on forced convection heat transfer in the presence of magneto and thermal radiation effects are investigated and can be used by different engineers working on industry.

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The thermal dispersion effects on the Darcy-Forchheimer natural, mixed and forced convection heat transfer with viscous dissipation effects over an isothermal vertical flat plate in a fluid saturated porous media are examined numerically. The coefficient of thermal diffusivity has been assumed to be the sum of molecular diffusivity and the dispersion thermal diffusivity due to mechanical dispersion. The non-dimensional governing equations are solved by using finite difference method with a Crank Nicolson implicit numerical technique. The results show that in natural, mixed and forced convection heat transfer, when the modified Darcy number is increased the heat transfer rates are enhanced and when the modified Forchheimer number are increased the Nusselt numbers are decreased. The effect of both viscous dissipation and thermal dispersion was found to increase both velocities and temperatures inside boundary layer and to reduce heat transfer rates.