Strengthening the thermal transfer of hot bodies is one of the topics that the old and new researches aim at due to its wide use in the fields of applied engineering. This research includes a study of thermal activity of five hot objects placed inside a cold chamber and rotating at constant speed. An equilateral triangular shape is the cross-sectional shape of the bodies. A rheologically complex fluid is poured into the chamber completely. A magnetic field of constant strength is applied to the x-direction of the chamber. The items studied here are: the rheological nature of the fluid by changing the value of power-law index (n = 0.8, 1 and 1.2), the rotational speed of the chamber is in terms of the Reynolds number (Re = 5 to 40), the magnetic field strength expressed in terms of the Hartmann number (Ha = 0 to 100) and finally buoyancy force (Ri = 0 to 50). The investigation was carried out using a numerical method adopted by a digital simulator with very high characteristics. The results showed that the thermal activity varies from one body to another. The effect of magnetic field on Nusselt number of the bodies decreases as the value of power-law increases.