Mechanical Engineering

Thermal performance of shell-and-heat-pipe heat exchanger (S-HPHE) and shell-and baffled heat-pipe heat exchanger (S-BHPHE) have been experimentally investigated. Methanol (CH3OH) has been used as working fluid of heat pipe. The mass flow rate of water on the shell side was varied from 30 lph to 60 lph, while on the condenser side it has been varied from 10 lph to 60 lph for all mass flow rate of hot water on the shell side of the heat pipe heat exchanger with baffles and without baffles. Heat input to the heat exchanger has been varied by varying the power input in the range of 1kW to 4kW. The results showed that, based on the shell-side flow rate and temperature of hot water, the effectiveness of heat-pipe heat exchanger with rectangular baffles is higher than that of the heat exchanger without baffles. The performance of heat-pipe heat exchanger with rectangular baffles with 1:1 ratio of mass flow rate of hot and cold water has shown minimum effectiveness. The shell and baffled heat-pipe heat exchanger (S-BHPHE) with 1:0.5 ratio of mass flow of hot and cold water shows the best performance.

The present paper describes research undertaken to evaluate the appropriateness of strategic performance measurement (PM) system and processes for small- and medium-sized Indian enterprises (SMEs). An evaluation is undertaken of three case studies to facilitate a performance model for the strategic improvement. This evaluation resulted in the identification of a process, based on its congruency to the theoretical model adopted. Data collected from SMEs is analyzed. The paper concludes with a number of recommendations to facilitate the application of model for SMEs.

Abstract In this work, effect of water depth on the single basin and double slope glass active solar still was studied. A solar collector is connected with solar still to convert the passive still into active. The set up was fabricated from a transparent glass .The thickness of the side glasses and bottom glasses are 8 mm and the upper slope glasses are 3.5 mm. All sides are made with same material. The bottom surface was coated with black coating. The solar still was insulated so that the heat dissipation could not take place to the surrounding. The length of the still is 1m and width is 0.5 m and depth of 10 cm was given and at this depth a slope of 150 was given. A flat plate solar collector is also added which is fabricated through Galvanised iron sheet whose thickness was 2.5 mm. It is in rectangular shape whose dimensions are (30cm x 15cm x 10cm). A copper tube is circulated with snake shape through which water is circulated. The study covers the influence of water depth of 1cm, 2cm and 3 cm with and without coal in the still productivity. The results stated that distilled water collection is highest for lower depth of 1 cm with and without coal. Even among lower depth, water with coal observed 21.9% increases in productivity in comparison with without coal.

In metal machining process turning operation of cylindrical parts are machined on CNC turning machine. Present work includes the machining of cylindrical component having non-concentric shape. Rotary fixture is designed for machining on CNC turning machine. To avoid unbalancing of fixture, fixture must be balanced by adding the counterweight on rotary fixture to minimize machining rejection. The fixture can be balanced by dynamic balancing machine. In project work rotary fixture will balance by Computer Aided Mass Balancing (CAMB) methodology. The methodology for balancing rotary fixture will use to calculate counterweight to be added on rotary fixture along with its position.

This paper addresses the development of a Human Powered Flywheel Motor (HPFM) operated forge cutter. This set-up is used to cut forage crop residues like maize Stover, sorghum Stover in dry condition. This cut Stover can be feed to cattle directly. The current practice by small livestock farmers is to cut forage manually by axe or machetes. The mechanized cutters also available which are hand operated as well as electric motor driven. But today there is severe power shortage in country like India, particularly in rural and remote area. It is convergent to the fact that the hand muscles are weaker than leg muscles. The concept of human powered flywheel motor is used to develop the pedal operated forge cutter. In this set-up flywheel is used as a motor or a store for energy. The operator pumps the energy into flywheel by pedaling bicycle- drive mechanism with a speed rising gear pair. After a one minute pedaling is stopped, and then flywheel shaft is connected to cutter shaft through spiral jaw clutch. The stored energy is enough to operate cutter effectively and efficiently. The test performance of developed cutter shows the remarkable improvements over hand operated forage cutter.

This work was carried out in order to optimize the friction phase parameters, of friction welding of M2 high speed steel, to AISI 1040 medium carbon steel, namely; rotational speed, friction pressure and friction time. The experiments were designed as per Taguchi method. The optimization of the experimentally obtained results was carried out by trying three mathematical models, namely; a multiple linear regression model without interaction effect, a multiple linear regression model with interactions effect, and a second-order polynomial regression model. The three models were evaluated using the experimental data, the coefficient of multiple determination R2, and Standard error of the regression (S), were used as the evaluation criteria of the models. The polynomial model was chosen, and optimized using a Genetic Algorithm. The optimal value of the joint strength of 411 MPa was obtained at the highest value of the time ( 44.9 sec.) and the pressure of 112 MPs and the speed of 1349 r.p.m.

The optimal expansion of rocket nozzle has been occasionally attained due to the variation of altitude as the ambient pressure of these altitudes decreases with increase in altitude. Optimal gas expansion occurs only at a particular altitude when the nozzle’s exit pressure (Pe) is equal to the ambient pressure (Pa) of that altitude. There are special altitude adoptable nozzles such as aerospike nozzles, expansion-deflection nozzles and others designed for optimal gas expansion as the altitude increases. However, these nozzles adds weight to the rocket and are expensive for production. This study has been conducted with an experimental Rocket nozzle designed and developed by NSS (Nair Service Society) College of Engineering Palakkad-Kerala, India using computational fluid dynamics to determine the effect of varying the combustion chamber pressure to balance the nozzle exit pressure to the ambient pressure as the rocket ascends in altitudes. From the results obtained, it was observed that there is a conformance of up to twenty three (23) kilometers using the nozzle understudy for which further variation in combustion chamber pressure developed subsonic flows and shock waves in the divergent section of the nozzle. Further analysis showed that the total mass of propellant consumed was 36% per stage engine less than most conventional method of launching rockets engines to orbits. This method of variation of chamber pressure to balance the nozzle exit pressure with the ambient pressure provides potentials for reduction in energy consumption of a rocket.

This paper presents an experimental investigation on the influence of cutting parameters of wire cut Electrical Discharge Machining (Wire-EDM) during the machining of Inconel825.Demand for better surface finish has been increasing recently for super alloys. The low rigidity and high material removal rate of Inconel alloys offers a challenging task in obtaining a better surface finish. The analysis of surface characteristics like surface roughness of Inconel-825 is carried out and an excellent machined finish can be obtained by setting the machining parameters at optimum level. Experimentation has been done by using Taguchi’s L18 (21x37) orthogonal array under different conditions of parameters. The response of surface roughness is considered for improving the machining efficiency. Optimal combinations of parameters were obtained by this method. The confirmation experiment shows, the significant improvement in surface finish (1.36µm) was obtained. Multiple linear regression model have been developed relating the process parameters and machining performance indicates the suitability of the proposed model in predicting surface roughness. The regression analysis are used to predict the error between actual and regression values of surface roughness in Wire EDM process. Experimental results demonstrate that the machining model is suitable and the Taguchi’s method satisfies the practical requirements.

In this study food waste from a restaurant, chicken waste and waste flour are used as feedstock. Along with this, one new biogas unit model is used and compared with the existing one for various features. The outcomes are documented. Different decisive parameters were verified and got compared with those generated from conventional type of feed stock in various AD processes mentioned in different literature searched. With the individual effect all above influensive parameters, the relation between them is also verified which shown consistent results.

This paper is a review on Warranty analysis, it basically explain about how warranty cost is important to handle carefully by all element of organization. Warranty cost needs uniformity to analyze throughout its user. Warranty cost analysis is challenging procedure as data become complicated when it consider different real life situations. Warranty claims are also part of effective warranty analysis. Different models explained by researches discussed to understand warranty analysis aspect. It studied different model for warranty analysis.