Investigation on the Tensile Strength of the Friction Stir Welded similar joint of Al/Al alloy using high thermal diffusivity backing plate material.

Friction Stir Welding process is a novel green solid state joining process for soft materials such as aluminium alloys. The weld quality is governed by the proper selection of parameters such as forge force rotational speed of the tool, welding speed, backing plate material etc. Thermal boundary condition at the bottom of the work piece plays an important role for obtaining the sound joint. The backing plate material governs these thermal conditions. In this case study, high thermal diffusivity backing plate material which consisted of AA2099 was used for joining of the plates of Structural Aluminium alloy. It was observed that the tensile strength was improved.

Modelling and transient simulation of a regenerative open Joule cycle reciprocating Ericsson engine for micro-CHP applications

The open Joule cycle reciprocating Ericsson engine shows promising results as regards small-scale cogeneration applications using renewable energies such as biomass or solar energy. Integrating a regenerative heat exchanger into a simple open Joule cycle helps to improve the engine performance thanks to the recovery of the waste heat of hot gases downstream the expander. A dynamic model of a small open Joule cycle Ericsson engine with a shell-andtube counter-flow regenerative heat exchanger is developed and simulated in order to study the operation stability, the system behaviour especially during transient phases, and the control strategies. Compared to the engine configuration without regeneration, simulation results predict a slower hot start-up transient followed by a stable operation of the engine with 21% increase of the engine thermal efficiency, 14.3% increase of the engine power output and a 529.5K exhaust air flow suitable for cogeneration purposes. Subjected to a selected perturbation (10kPa compressor inlet pressure drop) the engine reacts well and the operation is stabilized after a much longer transient phase. Valve settings are also addressed to maintain the system set pressure.

Theoretical prediction of performance of Single and Double pass solar air heaters with artificial roughened absorber plates

Investigations are carried out on artificial roughened absorber plates on Solar air heater. The roughness parameters are identified in to five basic profiles A, B, C, D and E. The profiles A, B and C are basic cubical and cylindrical profiles and the profiles D and E are categorized as rod arrangement of inline and staggered nature. Both frictional and heat transfer characteristics have been studied. Optimum results of frictional and heat transfer characteristics have been arrived out. Results show a higher value of frictional factor for the profile E. All reasons of variations have been justified and discussed. The deviation of friction factor from modified Balsius equation is within the limit of 4.32 %. Results also show higher value of Nusselt number for the inline rod arrangement of SAH than the other profiles.

Numerical Evaluation of Pollutants Emissions in a Homogeneous Methane/Air Micro Flame

Exhausting pollutant gas in a plug flow micro reactor are identified, described and predicted in this paper. For this, a premixed methane/air micro flame was simulated by a simplified chemical kinetics mechanism with four equations of Jones and Lindstedt. In addition to the Jones and Lindstedt model, one chemical kinetic mechanism with three equations describing the formation of thermal NO was integrated in Comsol 4.2a code, all that equations describing the production process and disappearance of the major chemical species. Simulations in stoichiometric and lean conditions with equivalent ratio ф equal to 0.9 and 0.7 show that the simulations with Jones and Lindstedt model provide a stable flame with the temperatures of the same order as that obtained with a detailed chemical kinetic mechanism as reported in the literature. Production of carbon dioxide (CO2) varies with the richness of the mixture. It is high with ф = 1 and in the order of 250 ppm, this value remains smaller than the required threshold for breathable air. Carbon monoxide (CO) is not found in the products of combustion due to the high temperatures at the outlet of the microreactor in the three cases

Investigation on Performance and Emission Characteristics of Low Heat Rejection Diesel Engine using Alternate Fuels

Petroleum based fuels play a vital role in rapid depletion of conventional energy sources along with increasing demand and also major contributors of air pollutants. Major contributors of today’s energy demand in India is being met with fossil fuels hence it is high time that alternative fuels for engines should be derived from indigenous sources .The enormous growth of world population, increased technical development and standard of living in industrial nations has led to this intricate situation in the field of energy, supply and demand. As India is agricultural country there is wide scope for the production of vegetable oils (both edible and non edible oils) from different oil seeds. The present work is focused only on non-edible oils as fuels for engines, as the edible oils are in great demand and far too expensive. All neat oils are to be collected and converted into their respective methyl esters through transesterification process. Thermal barrier coatings are becoming increasingly important in providing thermal insulation for heat engine components. Thermal insulation reduces in-cylinder heat transfer from the engine combustion chamber as well as reducing component structural temperatures. Likewise, Bio-diesel too has a potential as a promising alternative fuel to their diesel counterparts while being renewable, sustainable, and environmental friendly. In this work, the comparative effect of performance and emission characteristics of a standard compression ignition engine (STD) with Magnesium stabilized Zirconia (MSZ) coated (LHR) engines are investigated. Fuel-related properties have to be calculated and analyzed with those of conventional diesel engine. The effect of use of bio-diesel fuel on engine power, fuel consumption and thermal efficiency has to be calculated and analysed with that of conventional diesel engine.

Combustion and Emission Characteristics of Hydrous Ethanol–Gasoline Blends with Co-solvents in Spark-ignited Single cylinder Engine

In Brazil, hydrous ethanol is blended with gasoline and is successfully implemented in flexi fuel engines and it has the potential to directly compete with fossil fuels. However, the Ethanol Blending Program of India has not been successful due to non-availability of sugarcane molasses and could not achieve its 5% blending target based on the literature review study. Hydrous ethanol with co-solvent is proposed in this work as a promising blending oxidant instead of energy-intensive anhydrous ethanol in gasoline. This research work also delves into the challenges of using hydrous ethanol in gasoline blended fuel such as water tolerance, fuel properties, and fuel selection. The selected fuel sample 2EW30TBA10, which contains 30% hydrous ethanol and 10% TBA (t-butyl alcohol), and gasoline was selected based on water tolerance of the blended sample and stability. The combustion and emission characteristics of the selected fuel sample 2EW30TBA10 are studied in 4-stroke, single cylinder, water cooled engine, and the performances are compared to base fuel (E0) and reference fuel (E10). The significant contributions of the present research work are the development of combustion model using MATLAB using: Apparent heat release model (Model1) and Combustion pressure method (Model-2) and the results are validated using modified Wiebe function. There was an increase in brake thermal efficiency by 5% compared to base fuel (E0) and the specific fuel consumption (sfc) for 2EW30TBA10 fuel sample is 290 g/KWh as compared to E10, which is 300 g/KWh and for Petrol (E0), sfc is 360 g/KWh. There was a reduction in CO and HC emission compared to base fuel (E0) and an increase in NOx emissions. The cyclic variations of experimental results are validated using a non-linear regression model.

Experimental Investigation of Drag Reduction with polymer of Kerosene flow in a horizontal pipe

flow, where adding certain amount of drag reducing agent, such as polymer. From addition of that agent, it causes a dramatic frictional drag reduction. This work shows the effect of the pressure drop on a drag reduction along pipe in a horizontal placing with kerosene flow is investigated. The tested fluid was kerosene and poly isobutylene polymer (PIB) with 50 ppm (part per million), 75 ppm, and 100 ppm weight concentration of polymer: Experimental investigation gives more description of this phenomenon. The experimental results illustrate that pressure drop and pressure gradient decreases with increasing of polymer concentration and volume flow rate. The friction factor decreases with increasing of additive concentration and velocity. The drag reduction percentage increases with increasing the mean velocity, polymer concentration and temperature. The experimental results show that maximum drag reduction (DR %) about 19%.

Examination of Thermal Performance for Solar Air Heater with Modified Absorber

Everyday sun delivers enormous amount of energy towards earth. Solar energy received by earth in a day is equal to total energy consumed by us in whole year. Plenty of research has been done in utilizing solar energy efficiently. Solar air heater is always a hot topic between the researchers. Different configurations of absorber plate with roughness has been prepared and tested to increase efficiency. In this article, a Computational Fluid Dynamic analysis of solar air heater having triangular shaped bodies place over the absorber plate had been performed. Enhancement in the performance of solar air heater is resulted.

Performance Analysis of Solar Air Heater using CFD Simulation

Solar energy has emerged as one of the alternate to conventional sources of energy. Solar air heaters are one of the important devices to utilize solar energy. But, poor heat transfer coefficient is one of the major problem in solar air heater. In this research article, an attempt is made to increase heat transfer coefficient of solar air heater by putting Hollow bodies over the absorber plate. These resulted in increase in heat transfer coefficient, efficiency and increase in outlet temperature of air simultaneously

Effective numerical model for flow boiling of a nanofluid

Flow boiling of Al2O3-Water nanofluid has been investigated numerically using the Eulerian multiphase model in ANSYS FLUENT. The physical properties have been computed using the two phase mixture model. In the Eulerian multiphase model, Rensselaer Polytechnic Initiative (RPI) nucleate boiling model has been used for modeling boiling. Axial vapor fraction has been computed in case of flow boiling of water and heat transfer coefficient has been computed in case of flow boiling of Al2O3-Water nanofluid. The numerical results obtained were in good agreement with experimental results. The RPI model predicts the heat transfer characteristics quickly.