S. Shanmugam

The Accepting of Pipe Bends With Ovality and Thinning Using Finite Element Method

Thinning and ovality are commonly observed irregularities in pipe bends, which induce higher stress than perfectly circular cross sections. In this work, the stresses introduced in pipe bends with different ovalities and thinning for a particular internal pressure are calculated using the finite element method. The constant allowable pressure ratio for different ovalities and thinning is presented at different bend radii. The allowable pressure ratio increases, attains a maximum, and then decreases as the values of ovality and thinning are increased. An empirical relationship to determine the allowable pressure in terms of bend ratio, pipe ratio, percent thinning, and percent ovality is presented. The pipe ratio has a strong effect on the allowable pressure.

Thermodynamic analysis of solar parabolic dish thermoelectric generator

This paper presents thermodynamic analysis of solar parabolic dish thermoelectric generator (TEG) using energy and exergy efficiencies to a given set of operating parameters. The system contains solar parabolic dish concentrator (PDC) and TEG on its focal point, the analytical expression for energy and exergy efficiency equation is used for each component to evaluate its thermodynamic performance. It is found in TEG that the maximum energy loss is 95.80% and exergy loss is 89.28% when compared to PDC wherein the energy loss is 27.09% and exergy loss is 69.87%. The overall solar TEG energy efficiency and exergy efficiency obtained are 2.81% and 2.97% respectively.

Stress analysis of pipe bends subjected to internal fluid pressure using the finite element technique

Ovality and thinning are the commonly observed shape irregularities that are introduced during the forming process of pipe bends. Pipe bends with ovality and thinning are subjected to higher stresses than pipe bends with perfectly circular cross-sections. The stresses introduced in pipe bends with different ovality and thinning for a particular internal pressure are calculated using the finite element method. The constant allowable pressure ratio for different ovality and thinning is presented at different bend radii. The allowable pressure ratio increases, attains a maximum, and then decreases as the values of ovality and thinning are increased. A mathematical correlation to determine the allowable pressure in terms of bend ratio, pipe ratio, per cent thinning, and per cent ovality is presented.

Experimental Study on Solar Parabolic Dish Thermoelectric Generator

The applications of solar dish and thermoelectric generator have the research potential as green and clean energy generation from solar thermal route. In this paper, an attempt has been made to conduct an experimental study on small scale solar parabolic dish thermoelectric generator. The solar parabolic dish collector is fabricated using an unused satellite dish antenna fitted with polished aluminum sheet as concentrator surface. Thermoelectric generator consists of commercial thermoelectric modules embedded between the receiver plate and water cooled heat sink which is placed on the focal plane of manual tracking parabolic dish collector. The concentrated solar radiation and water cooled heat sink is the driving potential to generate electricity, various operating parameters like receiver plate temperature, power output and conversion efficiency with respect to solar radiation are studied. It is found that the receiver plate temperature is significantly affecting the power output. Also, in this study it is identified to reuse the unused dish antenna for solar collector and coupled with commercial thermoelectric module is simple fabrication method easy to adopt in the rural techno craft for small scale power generator to meet the isolated energy demands.

Sintered Fe-0. 8%C-1.0%Si-0. 4%Cu P/M Steel Preform Behaviour During Cold Upsetting

Cold upsetting experiments were carried out on sintered Fe-0.8%C-1.0%Si-0.4%Cu steel preforms in order to evaluate their deformation characteristics. Powder preforms of 86% of theoretical density, with two different ratios of height to diameter, were prepared using a suitable die set assembly on a 1.0 MN capacity hydraulic testing machine. Sintering was carried out in an electric muffle furnace for 1.5 h at 1 150 °C. Each sintered compact was subjected to incremental loading of 0.04 MN under dry friction condition till a crack appeared at the free surfaces. The experimental results were critically analysed, the stress as a function of strain and densification was obtained, then the work hardening behaviour was analyzed. It has been found that in the process of enhancing densification, strength and strain hardening is also induced during upsetting, but the work hardening behaviour is not homogenously enhanced against strain and densification.

A Numerical Model to Compute Heat Loss in the Focal Receiver of a Solar Parabolic Dish Thermoelectric Generator

Abstract This article presents a numerical model to compute the heat loss for a flat focal receiver of a solar dish collector to drive the thermoelectric generator. The focal receiver is embedded by flat thermoelectric modules with the absorber plate and it is enclosed in a glass cover. The steady state energy equations for the focal receiver are developed with standard assumptions. The heat loss from the receiver is estimated by an iterative method using the computer program. It is noticed that the convective heat transfer coefficient between plate and cover varies with spacing distance between the absorber plate and the glass cover. The receiver efficiency along with the glass cover temperature variation over the spacing of the plate is also noticed. The spacing distance between the absorber plate and the glass cover is suggested to be between 0.04 to 0.05 m for the focal receiver area of 0.1 m2.

Solar Parabolic Dish Thermoelectric Generator: A Technical Study

This article presents a technical study on a solar parabolic dish thermoelectric generator using annual average solar radiation data at site and its standard efficiencies. The energy balance equations are developed for the parabolic dish concentrator and thermoelectric generator. The numerical analysis is made to study its technical possibilities to meet a rural house annual energy demand of 16.80 kWh by a thermoelectric generator capacity of 120 W and parabolic dish concentrator surface area of 6.3 m2. It found that the proposed system is generating 24 and 7% of excess electricity at maximum and minimum radiation data respectively.

The Thermal Performance of a Low Cost Solar Parabolic Dish Collector for Process Heat

Abstract This article communicates thermal performance of a low cost solar parabolic dish collector. The parabolic dish collector is developed from low cost technology and is tested in the outdoors on a sunny day by measuring stagnation temperature on the flat absorber. The absorber, made of aluminum alloys and coated with black paint, is placed on the focal receiver. The calculated overall heat transfer co-efficient varies from 130 to 180 W/m2 K for the actual climate conditions at Tiruchirappalli, India. The thermal efficiency of the thermal collector is found to be 60% and the cost is minimized to half the cost of a collector that is available in the market with the same specifications.

An Experimental Evaluation of Energy and Exergy Efficiency of a Solar Parabolic Dish Thermoelectric Power Generator

A low-cost parabolic dish collector was made and tested with commercial thermoelectric modules made of bismuth telluride for electricity generation on its focal plane; the energy end exergy efficiencies were experimentally evaluated. It was found that the daily average temperature of the receiver plate in the solar parabolic dish thermoelectric generator was 127.4°C with the maximum of 189°C. The energy and exergy efficiencies were in the range 0.94–1.68% and 1.01–1.81%, respectively.

An Experimental Study on Drying of Non-parboiled Paddy Grains Using an Oscillating Bed Solar Dryer

This article explains the drying methodology for paddy grains in an oscillating bed solar dryer with different combinations of bed cover and reflecting mirrors. The bed is oscillated at a frequency of 2 Hz. The dryer dries 36 kg of non-parboiled paddy grains within the acceptable level of moisture content in just eight hours. Using the bed cover and the reflecting mirrors, the solar dryer gives the best drying performance. The average value of pick-up efficiency of the air and the dryer efficiency are 59.31% and 28.97%, respectively.