there is no specific value for the critical radius and the rate of heat flux around the thermocouple wire continuously increases with the wire diameter even when this is larger than the critical radius. Numerical simulation using COMSOL Multiphysics software also confirms that there is negligible thermal effect from the electrical insulation. Moreover, the experimental results agree well with those obtained by both the analytical and numerical methods and further confirm that the diameter of the thermocouple has an impact on the temperature measurement.

This study is a systematic review of research on heat transfer analysis in cavities and aims to provide a comprehensive understanding of flow and heat transfer performance in various kinds of cavities with or without the presence of fins, obstacles, cylinders, and baffles. The study also examines the effects of different forces, such as magnetic force, buoyancy force, and thermophoresis effect on heat transfer in cavities. This study also focuses on different types of fluids, such as air, water, nanofluids, and hybrid nanofluids in cavities. Moreover, this review deals with aspects of flow and heat transfer phenomena for only single-phase flows. It discusses various validation techniques used in numerical studies and the different types and sizes of mesh used by researchers. The study is a comprehensive review of 297 research articles, mostly published since 2000, and covers the current progress in the area of heat transfer analysis in cavities. The literature review in this study shows that cavities with obstacles such as fins and rotating cylinders have a significant impact on enhancing heat transfer. Additionally, it is found that the use of nanofluids and hybrid nanofluids has a greater effect on enhancing heat transfer. Lastly, the study suggests future research directions in the field of heat transfer in cavities. This study’s findings have significant implications for a range of areas, including electronic cooling, energy storage systems, solar thermal technologies, and nuclear reactor systems.

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(2017) Liquid cooling of non-uniform heat flux of a chip circuit by subchannels. Applied Thermal Engineering, 115, pp. 558-574. (doi:10.1016Engineering, 115, pp. 558-574. (doi:10. /j.applthermaleng.2016 This is the author's final accepted version.There may be differences between this version and the published version. You are advised to consult the publisher's version if you wish to cite from it. AbstractExperimental and numerical analyses have been carried out to study the effect of using subchannels in a liquid cooled heat sink for minimising the effect of hotspots generated on a chip or circuit. Two heat sinks -with and without subchannels -were fabricated in order to investigate this effect. The first device was manufactured with normal parallel channels while the second was designed to extract more heat by dividing the main channels above the hotspot into two subchannels. The inlet and outlet manifolds were designed with two inlet ports to minimise any potential mal-distribution of mass flow rate through the channels. Three thermocouples were attached to the bottom surface of the inlet manifold and another three attached to the outlet manifold to record surface temperature. Five different mass flow rates were generated under gravity by changing water container height. The results show that adding subchannels improves the uniformity of temperature distribution and reduces the maximum temperature. Moreover, at the same pressure head 79cm the thermal resistance is reduced 20% whereas the pumping power is increased by 11%.

Many researchers have conducted extensive experimental and numerical studies to explore the influences of multiple types of fuels. The high demand of energy in the world has led to the growing crisis and depletion of fossil fuels. Therefore, the researchers have focused on investigating renewable energy sources like biodiesel with the aim of suggesting, which energy is more friendly to the environment. Biodiesel has specifications for using it as an alternative fuel to traditional fossil fuels. Whereas, the use of biodiesel fuel in the original design of Diesel engine can emit a higher percentage of nitrogen oxides (NOx). Therefore, to reduce the harmful emissions of the fuel, the injection schemes and injector nozzle bore (INB) of the engine were modified. The present research combines the effect of the nozzle hole diameters and split injection scheme on the performance and combustion parameters of compression ignition (CI) engine was investigated. The engine was fueled with diesel blended of different proportions (Sp20, Sp40, Sp60, and Sp100) of spirulina biodiesel to prove the suitability of this blend as an alternative fuel. The injector nozzle has three injection holes, and the diameter of the three modified holes of the nozzle is changing (from 0.20 to 0.28 mm, step 0.02 mm) along with two types of scheme injection (double and triple). Furthermore, the influence of the direct injection Diesel‐RK model, single‐cylinder, four‐stroke engine; constant compression ratio (17.5:1), engine speed (1500 rpm), and naturally aspired engine at full load condition are studied. A comparison of the present simulation is compared with published results to validate the present simulation model for conventional baseline Diesel for validation. The simulation was done to investigate and present a comparative study with the conventional baseline Diesel engine. The double injection scheme shows a decrease by 1.8%, 1.7%, and 1.9% for parameters of peak cylinder pressure (PCP), peak cylinder temperature (PCT), and maximum rate of pressure rise, respectively. Whereas, the specific fuel consumption (SFC) and break thermal efficiency are increased by 8.7% and 9.33%, respectively. The results showed a reduction by 2.1%, 20.5%, 22.1%, and 3.2% in PCP, PCT, maximum rate of pressure rise, and break thermal efficiency, respectively. Moreover, the SFC is increased by 3.1% with the modified INB 0.28 (mm).