Bio-diesel is one of the most promising alternatives for diesel needs. Use of edible oil may create shortage of oil seeds for daily food, which necessitates identification of new kinds of non-edible vegetable oil. With this objective, the present work has focused on the performance of castor non-edible vegetable oil and its blend with diesel on a single cylinder, 4 stroke, naturally aspirated, direct injection, water cooled, eddy current dynamometer Kirloskar Diesel Engine at 1500 rpm for variable loads. Initially, castor neat oil and their blends were chosen. The physical and chemical properties of Castor oil were determined. In general, viscosity of neat vegetable oil is high, which can be reduced through blending with diesel and heating them. The heating temperature of the blends increases with the increase in the percentage of neat oils with diesel ranging from 70°C to 120°C before entering into the combustion chamber. The suitability of neat Castor oil and their blends are evaluated through experimentation. The performance and emission characteristics of engine are determined using Castor neat oil and their blends with diesel. These results are compared to those of pure diesel. These results are again compared to the other results of neat oils and their blends available in the literature for validation. By analyzing the graphs, it was observed that the performance characteristics are reduced and emission characteristics are increased at the rated load compared to those of diesel. This is mainly due to lower calorific value, high viscosity and delayed combustion process. From the critical analysis of graphs, it can be observed that 25% of neat Castor oil mixed with 75% of diesel is the best suited blend for Diesel engine without heating and without any engine modifications. It is concluded that castor non-edible oil can be used as an alternate to diesel, which is of low cost. This usage of neat bio-diesel has a great impact in reducing the dependency of India on oil imports.
The application of twisted tape inserts in heat exchangers allows higher heat transfer rates with a simultaneous loss of energy due to turbulence and friction. In a conventional approach, the twisted tape is placed in the entire length of the heat exchanger. The present study explores the effect of the length of the twisted tape insert at a different twist ratio (TR) for 4700 < Re < 22,800. The insert length ratio (LR) ranges from 0.25 to 1 and the TR ranges from 1.5 to 6. The maximum Nusselt number corresponds to the LR of 0.75 at a TR of 1.5. The maximum thermo-hydraulic performance is found to be 3.2 for the LR of 0.75 at a TR of 1.5.
The perforated twisted tapes are known to produce higher heat transfer rates with lower friction losses. The present study deals with the heat transfer and tube flow characteristics of a heat exchanger with a twisted tape having multiple V cuts with circular and elliptical perforations. Experimental data for the STT, PTT, MDVCT-CP, and MDVCT-EP tape geometries are collected for the twist ratio of 2-6 by varying the Reynolds number in the range from 2700 to 22,800. The effects of tape geometries on the Nusselt number in conjunction with friction factor are discussed and the entropy generation analysis is carried out to see the performance of different types of inserts. The formation of elliptical perforations with V cuts in a twisted-tape insert showed an improved thermohydraulic performance by reducing the energy loss due to friction. The maximum values of normalized Nusselt number Nu* and thermohydraulic performance factor η are found to be 3.26 and 1.88, respectively, corresponding to the elliptical perforated twisted tape with multiple V cuts having V cut depth ratio dc/W and V cut width ratio wc/W of 0.27, and twist ratio of 2.
The thermal performance of heat exchanger is considerably enhanced by the use of inserts. Twisted tape inserts are known for producing large heat transfer enhancements at the expense of fairly large friction penalty. With the objective to explore the effect of twisted tape with perforations and V cuts, the present study investigates the thermo-hydraulic performance of solid twisted tape, perforated twisted tape, and perforated twisted tape with double V cuts for the Reynolds number range of 2000–25000. During the experiments, the twist ratio of tapes is varied in the range of 2–6, while the depth ratio and width ratio of V cuts for perforated twisted tape with double V cuts are varied in the range of 0.2–0.27. The maximum enhancements in Nusselt number and friction factor were found to be 3.5 and 9.63, respectively, corresponding to the perforated twisted tape with double V cuts having V cut depth ratio and width ratio of 0.27 and twist ratio of 2.
The Present Investigation was carried out to study the effect of Alumina Metal Oxide (Al2O3) Nano Particles as additive for Palm Stearin Methyl Ester Biodiesel (B 100) and their blends as an alternate fuel in four stroke single cylinder water cooled, direct injection diesel engine. Alumina Nano Particles has high calorific value and relatively high thermal conductivity (30−1 W m K−1) compare to diesel, which helps to promote more combustion in engines due to their higher thermal efficiency. In the experimentation Al2O3 were doped in various proportions with the Palm Stearin Methyl Ester Biodiesel (B-100) using an ultrasonicator and a homogenizer with cetyl trimethyl ammonium bromide (CTAB) as the cationic surfactant. The test were performed on a Kirsloskar DI diesel engine at constant speed of 1500 rpm using different Nano Biodiesel Fuel blends (psme+50 ppm, psme+150 ppm, and psme+200 ppm) and results were compared with those of neat conventional diesel and Palm Stearin Methyl Ester Bio diesel. It was observed that for Nano Biodiesel Fuel blend (psme+50ppm) there is an significant reduction in carbon monoxide (CO) emissions and Nox emissions compared to diesel and the brake thermal efficiency for (psme+50ppm) was almost same as diesel.
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