Applied Mechanics and Materials Vols. 766-767

Abstract: Phase Change Materials (PCM) plays an important role in energy conservation, which is very attractive because of its high storage density with small temperature change. In this paper an attempt made to review number of paper based on Phase Change Materials (PCM) in various field of thermal energy storage systems and its applications. The Phase Change Material is the latent heat storage material. As the source temperature raises the chemical bonds within the PCM breaks and the material changes its phase from one phase to another phase. The material begins to melt when the phase change temperature is reached. The temperature then stays constant until the melting process is finished. Thermal Energy Storage deals with the storing of energy by cooling, heating, melting, solidifying or vaporizing a material, the energy becoming available as heat when the process is reversed. Hence it is important to study about phase change materials in thermal energy storage system.Keywords: Phase change materials, Thermal energy storage system, Encapsulation, solar system, Heating and cooling of building

Abstract: This article reviews the types of containment used on bulk storage in tank heat exchangers, macro encapsulation and micro encapsulation. The various schematics of containment used in latent heat thermal energy storage (LHTS) systems are summarized. The pressure drop due to encapsulation was reviewed and the effective ways of thermal conductivity enhancement techniques are discussed. Various containment methods like Shell type, hollow spheres, packed bed, micro encapsulation along with various experiments and investigations were categorized and listed. Around 50 related articles were reviewed on PCM innovation for further studies in this area.

Abstract: Solar energy is inexhaustible and renewable energy, lower in cost, sustainable and independent resource for producing electricity through photovoltaic systems. Building Integrated Photovoltaic (BIPV) system became one of the most promising technologies and recently experienced extraordinary growth. There is a consensus that these advancements lead to novel methods of domestic energy generation. This paper deals with design and analysis of unitized curtain wall with photovoltaic system for a proposed office building, which is having Curtain wall area of 4890 m². Using photovoltaic system in Unitized Curtain wall spandrel area to produce electricity through solar energy is an innovative method utilized in the proposed corporate office building. Recyclable materials like Aluminium, Glass and sealant are used in Curtain wall. By using Building Integrated Photovoltaic System (BIVP), 50% of Electricity required for the building is produced and its relative merits and cost are discussed.

Abstract: The spillway system allows stabilization of the water free level and avoids variation in free level of water along the flow passage as a function of flow rate. The main problem in the spillway is the profiling of weir crest. The criteria that need to be satisfied are there should be no flow separation from the crest and there should be uniform circumferential flow to avoid flow asymmetry in the flow passage. Separation of flow leads to large impact velocity of the falling water, which would lead to the large-scale entrainment of air in water. This paper describes the effect of spillway materials by coating over the weir and changing the profile on air entrainment characteristics in the downstream.

Abstract: Improvement of bumper system is crucial in the automotive industry. The main objectives are to increase the performance of the bumper and also to find a solution to reduce the cost of the bumper thereby facilitating the reduction of production cost. The cost of bumper is high owing to the amount of material used and various processes involved .The new design considers on reducing the amount of material use and adding improved hydraulics instead of normal bumper to give cushioning effect and also assures safety in low speed collision. The new design also improves the ability to absorb more impact load and increase the protection of the front car component. The methodology employed was the study of the front bumper system, design and fabrication. The suitable material that can be used as the bumper in terms of economical but still maintaining the toughness is Plastic-Polycarbonate (Molded) which is not expensive compared to the best material from the analysis of E-Glass Fiber, Plastic-Nylon Type 6/6 and Plastic ABS (Molded). The suitable material to be used for making beam is AISI E52100 Steel. Rearrangement of the mounting positions gives a different effect on the ability to withstand the impact force.

Abstract: The cooling water system is the industry’s primary way of conserving water. Modern water cooling towers were invented during the industrial age to dissipate heat when natural cooling water sources were available. The origin of cooling towers made the plant site selection independent of the availability of water source. The development of new, high efficiency film fills produced from light weights, flame retarded PVC reduces the size and weight of cross flow cooling towers. Today’s cooling tower combine the latest advanced materials to achieve the optimum balancing of High corrosion resistance, product durability and cost. Based on their specific functions, cooling tower components are designed using the materials with the best combination of corrosion resistance and physical properties. In this work, the coefficient of performance is determined by using Simpson’s rule and the performance of cooling tower at various L/G ratios is evaluated. The optimum approach of the tower is calculated.

Abstract: The research in material science had led to the discovery of new materials; but the real challenge lies in finding suitable application for those materials to be used in various engineering fields. Finding application for a new material is very difficult. Cellular materials have the most promising applications and proved to be satisfactory for its applicability due to their high stiffness-to-weight ratio, better crash energy absorption, fire resistance, non-toxicity, low thermal conductivity, magnetic permeability and lower density. Along with drastic weight reduction and material savings in the case of cellular structures, there are other application-specific benefits like noise and energy absorption, mechanical damping and filtration effects. Various materials exist where weight reduction is the only parameter to be considered but if low weight combined with good energy absorption characteristics or heat resistance is required, then metal foams could be preferred. Possible applications are seen in areas like light weight construction, crash energy absorption, noise control, transport industry, building industry, heat exchangers, purifiers, decoration and arts, etc,. The use of foams can satisfy the demand for light-weighing parts of several branches of industry.

Abstract: Many of the recent developments in the fields such as aerospace, automobile and nuclear engineering industries are partly due to the increasing usage of difficult-to-machining materials. The machining of these materials is very tedious and time consuming process. Electrical discharge machining process has been developed to overcome these difficulties. It is very important to reduce the recast layer thickness of the machined workpiece using EDM process for improving the surface integrity. In the present study, an attempt has been made to study the effect of conventional transistor pulse generator and modified iso current pulse generator on recast layer thickness. In this study, machining experiments have been conducted on AISI 202 stainless steel with transistor pulse generator and iso energy pulse generator in electrical erosion process. The effects of these pulse generators on recast layer have been evaluated and analyzed. From the experimental results, it has been detected that the iso energy pulse generator has produced lower thickness of recast layer than conventional transistor pulse generator.

Abstract: This paper titled “Study of composite helical spring using glass fibre with Araldite LY556 and XY54”. Currently, the composite materials in the automobile sector are used for construction of the body, interiors, chassis, hoods, electrical components etc...these components are in simplest form and also they are regular in shape and easy to manufacture. However the design of suspension system and complicated structures in the automobile are quite difficult to bring out the same shape and performance. The most important no gap of steel springs suspension are limited corrosion resistance, long-lasting manufacturing process and weight. This paper brings out incredibly a simple method to prepare the composite helical spring for any dynamic application. The glass fibre and resin mixed with 70:30 ratio and it is tested by compression testing machine as per ASTM. The mechanical properties, such as maximum load carrying capacity, deflection, stiffness Youngs’modulus, Shear stress and strain energy are determined using compression testing machine. The objective of this study is to reduce the weight of the spring, to obtain good surface finish, similar to steel spring, novel manufacturing methodology and identification of failure point rather than the maximum load.

Abstract: Sensors had gained importance in all fields of science and technology and development of real time small devices with high sensitivity for in situ measurements at low cost has gained momentum. Micromachined cantilever provides a solution to this hunt. MEMS cantilever are the simplest of all the other mechanical structures and hence is considered for the ease of fabrication. Here a chemical CO₂ sensor is considered with the metal oxide layer as receptor to adsorb the CO₂ molecules leading to an increase in mass and microcantilever as the transducer part converting the change in mass to change in natural frequency. The sensitive SnO₂ layer increases the mass and hence decreases the resonant frequency. The inherent natural frequency of the cantilever is altered by the sensitive coating on top of the beam and the residual stresses present on the structure. In this paper, we investigate the SiO₂ cantilever with SnO₂ deposited on the top surface. Initially the microcantilever is analytically modelled and then is fabricated and characterized experimentally. Finally the error % is analysed between the analytical model and experimental results.