Numerical simulation of solar parabolic trough collector with viscous dissipation in slits of arc-plug insertion

This paper investigates the effect of slits within the arc-plug insert of the solar parabolic trough receiver (PTR). In order to predict the performance of the parabolic trough collector (PTC) with arc-plug slits within the absorber tube; two different variants of slits of 2 mm and 1 mm thicknesses are considered. Then, each of the variants of slits with different thicknesses are varied in terms of numbers of their occurrence in the arc-plug. The 2 mm thickness slits are varied in 5, 7, and 9 numbers with uniform space of separation between them in the arc-plug. While 1 mm thickness slits are varied from 11 to 13 in numbers and also maintaining uniform space of separation between them like in 2 mm thickness slits. The objective is to determine the effects of viscous dissipation within the slits of the arc-plug of PTR; and also, the optimized version of the slit with its numbers. It is found that 2 mm slits with 9 in numbers showed the highest value of thermal efficiency as compared to all other cases. The thermal efficiency (eta) of the PTC with arc-plug slits are seen to be about 1.642 times of conventional PTC; whereas, 1.309 times of arc-plug without slits. Therefore, it is always beneficial to use slits within inserts of PTCs for its performance enhancement; but, the selection of slit's thickness and its numbers plays a vital role in its application.