Mechanical Engineering

The effect of penstock diameter on shaft power was studied as part of an ongoing development of a simplified pico-hydropower system with water recycling. The speeds of the turbine and alternator shafts and volume of water displaced were measured for each penstock diameter and nozzle area ratio. The shaft power, flow rate and efficiency of the turbine were computed. The mean efficiencies were 0.776 and 0.510 for penstocks diameters 0.0762 and 0.0381 m respectively. Hence, larger penstock diameters with small nozzle area ratios favor optimal system operation. The results show that the system can potentially impact Nigeria’s energy mix positively

In this paper analytically investigated the effects of water–Al2O3 nanofluid on the entropy generation through a coiled tube heat exchanger under uniform wall temperature condition in laminar regime. Nanofluid thermo-physical properties are obtained from literature or calculated from suitable correlations. It is found that adding nanoparticles improves the thermal performance of water-Al2O3 flow and with increasing volume constriction of nanoparticle, total entropy generation at fixed Reynolds number, decreases. By increasing , entropy generation decreases, also with increasing , total entropy generation increases.

Concern of environmental pollution and energy crisis all over the world have caused the research attention on reduction of diesel engine exhaust emissions and saving of energy simultaneously. An experimental study has been carried out for combined effect of Exhaust Gas Recirculation (EGR) system and varying inlet air pressure on performance and emission of diesel engine. As we know that the diesel engine are known for their high NOx formation and Exhaust Gas Recirculation (EGR) is being used widely to reduce and control the oxides of nitrogen (NOx) emission from diesel engines.

In this work , an experimental study to obtain the fatigue endurance limit for two aluminum alloy , 2024 and 5052 , were carried out at stress ratio R=-1 and rotary bending tests . The fatigue tests were performed at RT, 100 °C, 200 °C and 300 °C in order to establish the S–N curve equations. The fatigue endurance limits for both alloys at different temperature conditions were calculated at 107 cycles from the empirical S-N curve equations. It was found that the fatigue endurance limit decrease with increasing the temperature. Also the reduction percentage in fatigue endurance limit for 5052 Al. alloy was higher than that of 2024 Al. alloy.

In this current time of globalization and privatization, manufacturing firms are greatly relying upon the concept of failure mode effective analysis to fight with challenges of current market trends. This paper help to perceive and overcome the irregularities in plastic product by apply application of “FMEA”. It is focused on preventing problems, enhancing safety, and rising customer satisfaction. Due to implementation of FMEA can get larger benefits, such as improving product quality, reliability, and security, enhancing company's image and competitiveness, satisfying customer requirements, etc.

In this paper, a helical coil tube in tube heat exchanger was designed and used in carbon dioxide solar assisted heat pump system (SAHP) to provide hot water for domestic applications and to operate an air gap membrane desalination (AGMD) unit. Both theoretical and experimental studies to investigate the performance of the gas cooler with Glycol Ethylene 50% and water as coolants were performed. The experimental part to study the behavior of the carbon dioxide in the supercritical region was conducted on the R744 heat pump test rig located at Department of Energy and Process Engineering – NTNU. On the other hand, FEA using ANSYS Fluent 18.1 was used to conduct the theoretical analysis. The study includes effect of inlet temperature of both coolants, effect of discharge pressure, effect of mass flow rate of water, and logarithmic mean temperature difference (LMTD). Good agreements between Experimental and simulation results were achieved. Results showed that the outlet temperature of the refrigerant from the gas cooler decreased from 81 oC to 40 oC, with 0.085 bar average pressure drop due to the heat rejection process. The outlet temperature of the refrigerant from the gas cooler in case of water is 8 oC lower than with ethylene glycol 50%. The outlet temperature of water reached 57 oC which is enough for domestic applications and to operate the AGMD unit to produce fresh water. It is observed that the pressure drop in the refrigerant by using water as coolant is higher by 0.2 bar than when ethylene glycol 50% used. Results also revealed that the value of LMTD of the gas cooler using ethylene glycol 50% is 24.3 % higher than the LMTD value when using water.

Extensive studies were investigated Mechatronics of Automobile since the synergistic combination of classical electro-mechanic of automobile , computer science and automatic engineering were integrated to together at the beginning of the conceptual stage for the design of new models of automobile. More automobiles involve more pollution after fuel consumption. Although motors’ performance had been proving through its electronic computerized control unit, also called calculator, the limitation and the insufficient functional problem of motor’s injection system remain unsolved. To overcome this problem at different angle in contrast with early studies and conclusions, this paper focuses on motor’s electronic computerized control unit, such as Motronic injection system performance to highlight limitation and insufficient of motor’s injection system by using requirement and constraint analysis of electronic system on the sensors, calculators and injectors before the consequences of the failures of Mechatronics key elements in the motor’s injection system. The results show that electro-chemistry constraints, hardware and software requirements .This paper support the hypothesis that hybrid engine is more perfect for reducing fuel consumption and avoiding harmful gas emission than an internal combustion engine or an electric motor one alone .

Carburizing, though a widely used industrial thermo chemical diffusion process, it is associated with the problem of shape and size distortion in the carburized parts.  These distortions are troublesome as they adversely affect the performance of the parts in terms of life, and trouble free operation. The main objective of our present work is to optimize the distortion level, optimum case depth, and surface hardness value of the carburized parts made of EN 353 material. Taguchi’s mixed level series Design of Experiment was selected for optimization.  The significance of our study was that all the three stages of carburizing (Pre carburizing, Carburizing and Post carburizing) were considered for optimization.  An orthogonal array and ANOVA were employed to investigate the influence of major parameters on the three response variables namely Distortion level, Surface hardness and Case depth and optimum conditions were arrived at by applying high penetration depth, high hardness and low distortion are better as the strategies.

The goal of this paper is to design and implementation of wearable device which can be use as a guide to blind people by allowing them to imaging and response to spatial information by using IR transceiver then give an alarm as a vibration to skin by using a mobile vibrator. This vibration is give alarm to blind person to avoid obstacle, its look like sensory appendages of insects. This device can be used instead of dogs or cane to help blind people also it can be used by workers whose work in dangerous construction locations.

The mechanical advantage of using composite is high strength to weight ratios which increases their capabilities for aerospace, structural and automobile applications. The epoxy-coated reinforcement (ECR) has gained mainstream acceptance to extend the useful life of highway structures. The volume fraction of reinforcement affects the overall strength a composite and the orientation of fibers in matrix plays a significant role in determining the debonding behavior. The present work focuses on the determination of compressive strength and debonding behavior of steel reinforced epoxy composite with different orientation angles of fibers. The results revealed that among different orientations of fibers, reinforcement at 0° angles shows maximum compressive strength and least debonding than 45° and 90° angle of reinforcement.