This paper examines numerically by using the finite difference method the laminar steady magneto-hydrodynamic natural convection in an inclined T-shaped enclosure filled with different types of nanofluids. A uniform heat source is embedded on a part of the upper wall of the enclosure. Both left and right sidewalls of the enclosure leg are maintained at a constant cold temperature, while the other portions of the enclosure walls are considered adiabatic. A magnetic field is applied vertically downward on the bottom wall of the enclosure. Based on the numerical results, the effects of the dominant parameters such as Rayleigh number, Hartmann number, inclination angle, solid volume fraction, location and length of the heat source and enclosure aspect ratio are examined. The numerical results are obtained for Hartmann number varying as 0⩽Ha⩽100, inclination angle varying as 0⩽Φ⩽90°, Rayleigh numbers varying as 103⩽Ra⩽106, aspect ratio 0.3⩽AR⩽0.9, heat source length 0.2⩽B⩽0.8, heat source location 0.2⩽D⩽0.5 and the solid volume fractions varying as 0⩽ϕ⩽0.2. Comparison with previously published numerical work is performed and a good agreement between the results is observed. It is found that the mean Nusselt number increases with the increase of Rayleigh number, inclination angle, aspect ratio, heat source location and volume fraction of nanoparticles, while, it decreases when the Hartmann number and heat source length increase

Utilizing ultrasonic excitation as an active method for studying the rate of heat transfer has gained considerable attention recently. The present study investigated the effects of ultrasonic excitation on the heat transfer rate in a fin-and-flat tube heat exchanger experimentally. The performance of the heat exchanger was investigated with and without the presence of ultrasonic excitation. A comprehensive parameter study was attempted, so several parameters, including ambient temperature, flow rate, air passing velocity, Reynolds number, and Nusselt number, were studied in a relatively wide range. An adequate uncertainty test, as well as a validation assessment, is provided to certify the credibility of the obtained results and the hired facility. The results revealed that reducing the flow rate, ambient temperature, and air passing velocity on the heat exchanger increased the ultrasonic excitation’s effects. The highest heat transfer enhancement in the present experiment was 70.11%, measured at the lowest air passing velocity and ambient temperature with a Reynolds number 2166. The data presented in this paper will be useful for the optimal design of ultrasonic vibrating fin-and-tube heat exchangers.