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In India, Silk industry plays an important part in textile industry. Muga silk, the golden yellow silk is quite unique to Assam, North-east India where its production is regarded as an important tool for economic development. But, outdated manufacturing technology is followed during the silk production in Assam. The existing cooking process of silk cocoons consists of boiling of silk cocoons in a stainless steel vessel along with water and soda in an open fireplace which is highly energy inefficient. Therefore, two modified systems have been designed; one having cylindrical boiling chamber (vessel) and the other having spherical boiling chamber (vessel). Both the chambers are having a cocoon heating chamber associated with them for cooking and drying of silk cocoons simultaneously. These designs are further classified into two types of designs based on channel and nozzle type combustion chambers. Therefore, the main objective of this paper is to improve the existing designs to maximize the utilization of heat carried by the combustion gases. These modified systems are analysed by using Computational Fluid Dynamics (CFD) selecting standard k–є model. From the analysis, it is seen that these new systems having nozzle type combustion chambers are more efficient than the systems having cylindrical combustion chambers and if these systems are used in silk production, it will be very beneficial for the silk industry as well as for our society.

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In this paper, blade-fluid interactions of high-solidity unsymmetrical and symmetrical blade H-Darrieus rotors have been studied using detailed computational fluid dynamics simulations to obtain insight into their performance in low wind speed conditions. In the existing literature, such comparative studies of high-solidity rotors are few, but are required for improving their steady-state performance at low wind speeds. For this study, a thick S815 unsymmetrical airfoil and a NACA0018 symmetrical airfoil have been selected. The effects of variations of low wind speeds have been quantified with respect to their impact on the blade-fluid interactions of the rotors at various azimuthal positions. It has been found that in the advancing stroke, a trailing-edge vortex on the suction side of the S815 blade H-Darrieus rotor as well as the leading-edge shape of the S815 blade are responsible for the higher performance of the unsymmetrical blade rotor. Moreover, in the returning stroke, a strong recirculating secondary vortex interacts on the pressure side of the S815 blade H-Darrieus rotor, which also augments the performance of the unsymmetrical blade rotor. For the symmetrical blade rotor, there are no such blade-fluid interactions with the advancing and returning blades.

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