Search

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. [DOI: 10.1115/1.4001423] Keywords: pipe bend, pipe ratio, bend ratio, oval shape, thinning, pressure ratio, membrane stress, allowable pressure

This article explains the mathematical modeling of dual inclined oscillating bed with double-pass solar dryer for drying of non–parboiled paddy grains using hot air which receives from double-pass flat plate solar collector. The trays were kept inclined to the horizontal and provided an oscillation for the movement of grains from the entry to the exit of the trays. The experimental model predicts the change in temperature of drying air at entry, middle, and exit of the drying chamber to compute the variation in the moisture content of the paddy grains and collective mass of the dried paddy grains received from the dryer model. The non–parboiled paddy grains were dried in a physical model with a constant bed tilt of 0.5º and oscillated with a frequency of 2.75 Hz. The experimental results attained from the physical model are correlated with the predicted values. The average error and the standard deviation of the moisture content of the dried paddy grains are 3.13% and 0.83, respectively, and those of the collective mass of the dried paddy grains received from the dryer are 4.63% and 1.92, respectively. [ABSTRACT FROM AUTHOR]