Applied Mechanics and Materials Vol. 787

Abstract: Composite materials are in-homogenous, anisotropic and cause high tool wear at high cutting speeds in machining. Industrial practices worldwide reveal a need to use high speed machining to achieve the desired material removal rate, surface finish and to reduce cost cutting. In this research work, impact of turning glass fibre reinforced polymer tube with two contrasting turning tool inserts such as titanium aluminium nitride and tungsten carbide have been analysed. The turning was conducted at low to high cutting conditions up to spindle speeds of 2000 rpm and feed rate of 0.446mm/rev. The cutting force, feed force were acquired with a strain gauge based dynamometer, the chip cross section was observed using scanning electron microscopy and the temperature was sensed with a infra red thermo sensor. The advanced titanium aluminium nitride insert shows better machining characteristics across cutting speeds.

Abstract: Aluminium matrix composites have received the attention of numerous researchers, because of its attractive properties like high strength, good thermal conductivity and more strength to weight ratio. Application of the conventional welding processes for aluminium matrix composites, facilitates the formation of undesirable phase at the welded region, which limits the wide spread application. The objective of this paper is to review the literatures belonging to the friction stir welding of the composites and explore the challenges associated to maximize joint efficiency. The major contribution of this paper is to study the issue of welding of ex-situ and in-situ composites, various process parameters, properties of joint and post weld heat treatment process to improve the joint efficiency. This literature review provides some research gaps in the friction stir welding of composites.

Abstract: In LNT Catalysts, oxidizing agents are added for reducing the levels of NOxemission. In the current work three sets of LNT catalysts were prepared by dipping them in three independent solutions containing i) Barium nitrate, ii) Copper nitrate + Silver nitrate, iii) Copper nitrate + Ferric nitrate + Barium nitrate. These three catalysts were then tested in dual-cylinder four-stroke Simpson 217 DI Diesel engine coupled to electrical dynamometer with wire wound resistance loading device. LNT process was studied and performance of the various chemicals used to reduce the NOx emission under various load conditions in lean burn engine was evaluated. 60% NOx conversion was obtained for LNT catalyst coated with barium + copper +ferric nitrate.

Abstract: Fuel spray and atomization characteristics play a vital role in the performance of internal combustion engines. Petroleum fuels are expected to be depleted within a few decades, finding alternative fuels that are economically viable to replace the petroleum fuel has attracted much research attention. In this work spray characteristics such as spray tip penetration, spray cone angle and spray area were investigated for Karanja oil methyl ester (KOME), Jatropha oil methyl ester (JOME) and diesel fuel. The KOME and JOME sprays were characterized and compared with diesel sprays at different injection timings. The macroscopic spray properties were acquired from the images captured by a high speed video camera employing shadowgraphic and image processing techniques in a spray chamber. The experimental results showed that biodiesel fuels had different features compared with diesel fuel after start of injection (ASOI). Longer spray tip penetration, larger spray area and smaller spray cone angle were observed for biodiesel (JOME, KOME) due to its higher density and viscosity than that of diesel fuel.

Abstract: Fossil fuels are exhausting quickly because of incremental utilization rate due to increase population and essential comforts on par with civilization. In this connection, the conventional fuels especially petrol and diesel for internal combustion engines, are getting exhausted at an alarming rate. In order to plan for survival of technology in future it is necessary to plan for alternate fuels. Further, these fossil fuels cause serious environmental problems as they release toxic gases into the atmosphere at high temperatures and concentrations. The predicted global energy consumption is increasing at faster rate. In view of this and many other related issues, these fuels will have to be replaced completely or partially by less harmful alternative, eco-friendly and renewable source fuels for the internal combustion engines. Hence, throughout the world, lot of research work is in progress pertaining to suitability and feasibility of alternative fuels. Biodiesel is one of the promising sources of energy to mitigate both the serious problems of the society viz., depletion of fossil fuels and environmental pollution. In the present work, experiments are carried out on a Single cylinder diesel engine which is commonly used in agricultural sector. Experiments are conducted by fuelling the diesel engine with bio-diesel with LPG through inlet manifold. The engine is properly modified to operate under dual fuel operation using LPG through inlet manifold as fuel along FME as ignition source. The brake thermal efficiency of FME with LPG (2LPM) blend is increased at an average of 5% when compared to the pure diesel fuel. HC emissions of FME with LPG (2LPM) blend are reduced by about at an average of 21% when compared to the pure diesel fuel. CO emissions of FME with LPG (2LPM) blends are reduced at an average of 33.6% when compared to the pure diesel fuel. NOx emissions of FME with LPG (2LPM) blend are reduced at an average of 4.4% when compared to the pure diesel fuel. Smoke opacity of FME with LPG (2LPM) blend is reduced at an average of 10% when compared to the pure diesel fuel.

Abstract: Enhancing the efficiency of normal diesel cycle and gasoline cycle is gaining more importance because of depleting fossil fuel resources and other environmental issues. In normal operation the efficiency of diesel cycle is about 37 - 44%. So diesel cycle efficiency should be increased or otherwise it should be replaced with alternate fuels. Increasing the efficiency of the cycle leads to lower fuel consumption and other economic benefits. Thermal efficiency of the diesel mainly depends on compression ratio and combustion parameters such as injection timing, injection pressure and ignition delay period. Thermal efficiency also depends on fuel properties such as viscosity, density and cetane number (CN). This paper discuss about the performance evaluation of diesel fuel in a CI engine when the fuel properties are pre-enhanced by crystal agitation. In this experiment different size (Micro and Nano) SiO₂ crystals are used with commercial diesel fuel in the storage tank and the performance and emission test are conducted. Results of these samples are compared with neat diesel fuel performance.

Abstract: Hydrogen is a zero emission alternative gaseous fuel generally used in internal combustion engine with single fuel or duel fuel mode. In this work the Hydrogen is introduced in inlet manifold in addition to main diesel fuel used in the engine. The different flow rate of hydrogen fuel is used in this work are from 2 lpm to 10 lpm at 2 bar pressure. Here the single cylinder, direct injection, diesel engine with 1500 rpm rated speed is used for test. In addition to hydrogen, the exhaust gas also introduced in the inlet manifold with various percentages namely 10% and 20%. The engine is loaded with eddy current dynamometer .The engine performance and emissions of various combination of hydrogen flow rate and exhaust gas recirculation (EGR) were analyzed. The result showed that in 8 lpm hydrogen flow rate without EGR the BTE increased and BSFC decreased. At the same condition the HC, CO emissions reduced and NOx emission is increased. But NOx emission with 10% and 20% EGR is reduced.

Abstract: Increase in engine speed increases the in-cylinder turbulence and hence the rate of mixing. However, it is difficult to directly measure the mixing rate and relating its effect on emissions. Hence, in this paper, the comparison of mixing rate at different engine speeds are demonstrated with a multi-zone phenomenological model which has been developed and validated on a wide range of engine operating conditions. The mixing rate is evaluated using a standard quasi-dimensional k-ε formulation. The quantitative predictions of mixing rates at different engine speed substantiate the cause of soot emission reduction at higher engine speed.

Abstract: Common rail direct injection system (CRDI) offers the potential to achieve optimal combustion and emission characteristics. An empirical analysis of engine combustion process incorporating Wiebe type burn rate law approach is useful not only in understanding the combustion characteristics of a CRDI engine but also aids in diagnosis and control of the combustion process wherever required from the performance and emission standpoint. This paper presents a methodology for applying the burn rate law for common rail direct injection diesel engines adopted with split injection by using Wiebe’s correlation. The analysis reveals that while the empirical constant ‘m’ (shape factor) for both pilot and main injections is independent of engine load and seems to be affected by engine speed only, the constant ‘a’ (efficiency parameter) seems to be influenced by the engine speed, load and injection conditions. A correlation for these empirical constants with the respective parameters of dependence can be formulated which can be used to analyze the effect of change in engine operating conditions on combustion characteristics without conducting engine experiments.

Abstract: An experimental investigation was conducted to analyse the performance and exhaust emissions of Kirloskar AV-I Compression ignited air cooled engine fuelled with diesel and cotton seed oil blends (80% of diesel and 20% of cotton seed biodiesel).Experiments were conducted at various concentration of urea solutions ranging from 30 to 35% at a constant flow rate of 0.75 litres per hour. The results indicated that urea injection with titanium dioxide as selective catalyst in the exhaust pipe caused a 47.9% of NOx reduction for diesel at full load condition and at a constant flow rate of 0.75lit/hr with an urea concentration of 35%.Also the results showed that urea injection with titanium dioxide as selective catalyst in the exhaust pipe caused a 68.5% NOx reduction for biodiesel which was achieved with a constant flow rate of 0.75lit/h with an urea concentration of 32.5%.Thus Biodiesel (C20) fuelled CI Engine with SCR is a very effective and suitable replacement for petroleum based diesel fuelled CI Engine with SCR. ANOVA analysis was done and resulted that the null hypothesis is rejected. A high p-value (0.104) had suggested that beta plays a less significant role in the model and a low p-value (0.012) suggests that beta plays a significant role in the model. Overall ANOVA analysis disclosed that percentage of urea solution has a major impact on NO_X emissions than HC and CO emissions.