Ar. Veerappan

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.

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.

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.

Thermal Performance of a Solar Dryer with Oscillating Bed for Drying of Non-parboiled Paddy Grains

There are many solar dryers for drying agricultural produce. This article explains the drying methodology and the thermal efficiency of the solar dryer with the bed tilted to a certain angle and oscillated at a particular frequency while drying non-parboiled paddy grains. The oscillating bed solar dryer dried 36 kg of non-parboiled paddy grains in just a day to the required level of moisture content, and the average moisture present in the dried grains was 13.56%. The average dryer thermal efficiency was 26.3%. The specific moisture extraction rate was 1.11 kg/kWh.

Effect of Shape Imperfections on Thin-Walled Pipe Bends under Out-Of-Plane Moment and Internal Pressure

This paper quantifies the effect of ovality and thinning/thickening of thin-wall pipe bend modeled using the geometric parameters of r/t=15 and 20 and λ=0.1 to 0.3. For each model the ovality and thinning is varied from 5% to 20 % in steps of 5 % .The collapse loads were obtained from twice-elastic-slope method of pipe bends subjected to out-of-plane moment with and without internal pressure. Large displacement analysis was performed on elastic-perfectly plastic material using the nonlinear FE package of ABAQUS. The analyzed shows that the thinning effect is insignificant and ovality produce the significant effect of upto 27.7% decrease in collapse load for pipe bend subjected to combined moment and internal pressure.