Recent Advancements in Thermal Performance Enhancement in Microchannel Heatsinks for Electronic Cooling Application

Thermal management of electronic equipment is the primary concern in the electronic industry. Miniaturization and high power density of modern electronic components in the energy systems and electronic devices with high power density demanded compact heat exchangers with large heat dissipating capacity. Microchannel heat sinks (MCHS) are the most suitable heat exchanging devices for electronic cooling applications with high compactness. The heat transfer enhancement of the microchannel heat sinks (MCHS) is the most focused research area. Huge research has been done on the thermal and hydraulic performance enhancement of the microchannel heat sinks. This chapter’s focus is on advanced heat transfer enhancement methods used in the recent studies for the MCHS. The present chapter gives information about the performance enhancement MCHS with geometry modifications, Jet impingement, Phase changing materials (PCM), Nanofluids as a working fluid, Flow boiling, slug flow, and magneto-hydrodynamics (MHD)

Effective utilization of B20 blend with diethyl ether and ethanol as oxygenated additives

In the recent times' fatty acid methyl ester popularly called as biodiesel has become more prominent alternate fuel for compression ignition engines based on a single fuel concept. Since, use of neat biodiesel on a large scale is raising certain difficulties and is being adopted in a blended form with petro-diesel fuel and B20 blend has become standardized. However, the HC and NOx emissions of B20 are still on the higher side. Present work aims at experimental evaluation of a single cylinder water-cooled diesel engine by adopting various proportions of ethanol and diethyl ether blends in order to improve performance and emission characteristics of B20 blend. Besides employing different amounts of ethanol and diethyl ether, simultaneous influence of injector nozzle hole size and fuel injection pressure are also investigated to arrive at an optimum configuration. Brake specific fuel consumption and hydrocarbon emissions values are lower with B20 and DEE 5 whereas B20 with DEE15 yielded lower NOx emissions. It is observed that addition of oxygenates have improved the combustion process and lower emissions are obtained. The present investigation revealed that blends with oxygenated additives having higher Cetane rating are superior to neat blend

Internal and External Influences on Hydro-Thermal Behavior of Micro-channel Flow

Microchannel flow is an effective solution for many engineering problems. Application of microchannels is found in various fields such as thermal management of electronics, micro-combustors, biomedical industries, MEMS. In microchannel flow, some internal and external influences such as surface roughness, electric and magnetic fields are very significant and commonly neglected in macro-scale flow. Early research works on microchannels stated that the conventional theories of macro-scale flow were not applicable for microscale flows. Finally, researchers are concluded that the deviation in conventional theories in the case of micro-scale flow is because of neglecting the internal forces, surface roughness, surface wettability, etc., which play a prime role in micro-scale flows. In this chapter, the behavior of microchannel flow under the internal and external influences is discussed. The heat transfer and hydrodynamic characteristics of microchannel flow under the external magnetic field and electric fields are presented. The effect of surface morphology, roughness, electro-osmotic effect, electrophoresis, internal heat generation, and analysis methods is discussed