Browsing by Author "Ali, Hafiz Muhammad"

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    Heat transfer and fluid flow characteristics investigation using detached ribs in an axisymmetric impinging jet flow
    (Springer, 2022-10-15) Rasheed, Adnan; Allauddin, Usman; Ali, Hafiz Muhammad; Uzair, Muhammad; Verdin, Patrick G.; Siddiqui, Yasir H.
    This research work is directly concerned with the heat transfer involved in a single jet flow covering a heated surface having detached ribs present above the surface. A computational study has been conducted to check the effect due to the presence of such detached ribs. The generalized k−ω (GEKO) turbulence model with Reynolds-averaged Navier–Stokes equations formulation has been adopted after validation with the relevant experimental data from the literature. A rectangular rib design was selected for which rib width, height, clearance, pitch and first rib radial distance were varied to study their effect on heat transfer. Local heat transfer distributions were investigated over the target surface, especially focusing on the ribs-based region for different nozzle positions. The thermal performance with and without ribs is compared. A maximum increase in heat transfer of 64% was observed for a normalized nozzle to plate spacing z/d = 0.5.
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    Thermal management of electronics devices with PCMs filled pin-fin heat sinks: A comparison
    (Elsevier, 2017-11-05) Ali, Hafiz Muhammad; Arshad, Adeel; Jabbal, Mark; Verdin, Patrick G.
    The present paper covers the comparison of two different configurations (square and circular) pin-fin heat sinks embedded with two different phase change materials (PCMs) namely paraffin wax and n-eicosane having different thermo-physical properties were carried out for passive cooling of electronic devices. The pin-fins, acting as thermal conductivity enhancers (TCEs), of 2mm square and 3mm circular fin thickness of constant volume fraction of 9% are chosen and input heat fluxes from 1.2kW/m2 to 3.2kW/m2 with an increment of 0.4kW/m2 are provided. Two different critical set point temperatures (SPTs) 45°C and 65°C are chosen to explore the thermal performance in terms of enhancement ratios, enhancement in operation time, latent heating phase duration, thermal capacity and conductance. The results show that 3mm diameter of circular pin-fins has the best thermal performance in passive thermal management of electronic devices.