• Energy Research

Abstract Nanofluid performed a very crucial role in nuclear power plant for improving heat transfer. Due to high thermal conductivity of nanofluid heat transfer capacity in nuclear reactor can be thousand times larger than conventional fluids like water. So the efficiency of nuclear reactor is improving and also reducing the thermal hydraulics problems. It opens a new gateway for gaining higher energy optimization. For improving the heat transfer in light water reactor, SiO2-water based nanofluids properties were used for numerical investigation. Heat transfer of nanofluid can be functions of volume concentration, physical properties and size of nanoparticles etc. Density, thermal conductivity, specific heat and viscosity were investigated and operated as a basic data for ANSYS 14. In this numerical investigation three value of weight concentration of nanoparticles in the range of 1%, 2% and 3% were used. A uniform heat flux of 1000 (kW/m2) is applied at the wall of annular rod. The numerical method which is available in CFD package of Ansys CFX 14 has been used here. Turbulence models of k–ω has been used in this numerical analysis. Validation of result has been done by analytical equations. Numerical investigation of various effect on characteristics of heat transfer in light water nuclear reactor by using SiO2-water based nanofluid is the key objective of the study. Coefficient of heat transfer and temperature of clad wall profiles are plotted without nanofluids and with nanofluids.

Abstract Waste cooking oil biodiesel is considered a common way to generate clean energy in all countries. It can be used efficiently, like fossil fuel quality. To overcome the problem of poor combustion, an increase in the NOx and unburned hydrocarbon emissions, liquid, or solid additives were commonly used to improve combustion and emissions properties. In this study, the Cyclohexane (C6H12) as volatile organic and the flammable liquid compound has been applied as a micro additive for B60D40 fuel blends. Its effect on diesel engine combustion, performance, and emissions has been experimentally investigated. The C6H12 added into the diesel/biodiesel blends at different concentrations of 5, 10, and 15 % by volume basis. Two values of injection pressure have tested experimentally at different Cyclohexane concentrations. The experiment activity changed the fuel injection pressure of 150 and 250 bar, respectively, while the WCOB blends of B60D35c5, B60D30c10, and B60D25c15 have been used. The obtained results have been compared with the commercial diesel#1 and B60D40 fuel blends, respectively. The measured data show that the Cyclohexane additives dramatically improve engine emissions as well as engine performance. The CO, HC, and smoke density have decreased by increasing the Cyclohexane dose as a flammable additive. The NOx emission was reduced by increasing the C6H12 due to the fast combustion process and enhancing the premixed combustion period. Moreover, the increased injection pressure from 150 bars to 250 bars reduces the engine BSFC, HC, CO, NOx, smoke density, increasing engine BTE, CO2 emissions, and exhaust gas temperature.

Abstract Solar cavity receiver is an integral part of the solar parabolic dish collectors used for absorbing concentrated solar irradiation. The performance of the receivers can be enhanced utilizing different types of heat transfer fluids (HTF) and modified geometries. The thermal performance of a redesigned cavity receiver with solid semi-circular tube attached to its surface was investigated using CFD three-dimensional simulation. The influence of operating and geometric parameters (i.e., inlet mass flow rate and inlet temperature) were investigated. The results obtained shows that, redesigned solar cavity receiver has thermal efficiency of 8.49-10.27% higher than a normal cavity receiver with an inlet flow rate of 0.01-0.04 kg/s under the same environmental and operating conditions. The temperature of outlet of HTF increases with increases in inlet temperature for Therminol66 oil. The comparison of thermal performance using different HTF (i.e., Therminol66, Ethylene Glycol, Water) is also conducted and it is found that Therminol66 oil gives 9% and 17% higher outlet temperature than ethylene glycol and water respectively at intake flow rate of 0.02 kg/s.

Tremendous growth in the number of automobiles in developed and developing global economies has exorbitantly boosted competition for petroleum products. Petroleum products derived from fossil fuels are predominantly responsible for environmental pollution as unburnt hydrocarbon (HC), carbon monoxide (CO), oxides of nitrogen (NOx) & carbon dioxide (CO2) emissions are released from the fossil fuel combustion. In the view of increasing environmental pollution and stringent emission norms, the present study is concentrated on using Jatropha biodiesel as an alternate fuel source to run variable compression ratio (VCR) diesel engine. The characteristics of VCR diesel engine emission have been evaluated under different compression ratio (CR), operating conditions of load & pressure of fuel injection. In this research work, Jatropha biodiesel diesel blend B30 (30% biodiesel and 70% diesel) and B0 (100% diesel) have been taken as fuel to run the engine. For conducting experiments, load has been varied from 0 to 12 Kg, CR from 14 to 18 and FIP from 180 to 270 bar as per the model of Response Surface Methodology experiments. The experimental investigation showed that the use of the B30 blend reduces HC & CO emissions by about 16.7% and 24% correspondingly in comparison to diesel. However noteworthy rise in NOx & CO2 emissions rate recorded by using the B30 blend as that of diesel. It has been shown that with enhancing in load & CR, HC&CO emissions decreased significantly however increase in CO2 and NOx observed. Advancing FIP, significantly decreases HC & CO emissions as well as tends to increase NOx and CO2 emissions.