Losses in turbine cascade are categorized as profile loss, secondary loss, tip clearance loss and annulus loss. Profile loss occurs due to development of boundary layer on surface of blade [1]. Increase in thickness o...Losses in turbine cascade are categorized as profile loss, secondary loss, tip clearance loss and annulus loss. Profile loss occurs due to development of boundary layer on surface of blade [1]. Increase in thickness of boundary layer and adverse pressure gradient increases profile loss. Secondary loss occurs due to turning of flow through flow passage which results in blowing of energy from pressure side to suction side. In turbine rotor blade suction surface leads and tip clearance loss occurs due to leakage of air from pressure side to suction side of the blade through tip clearance. Annulus loss occurs due to development of boundary layer on stationary row of blade. It also occurs in moving row of blade but in moving row of blades boundary layer is scraped by flow over the blades. This paper presents effects of variation of pitch-chord ratio on secondary loss.展开更多
Fins are used for enhancement of heat transfer. Triangular fins are arranged in form of nozzle and heat transfer coefficient is calculated. Angle of taper of nozzle is changed i.e. angles of triangles are varied and t...Fins are used for enhancement of heat transfer. Triangular fins are arranged in form of nozzle and heat transfer coefficient is calculated. Angle of taper of nozzle is changed i.e. angles of triangles are varied and then heat transfer coefficient is calculated. Total finned area of all fins is almost the same. Number of fins and orientation of fins are different. In this study to calculate heat transfer coefficient of unfinned area open channel is considered where density and pressure are constant. This study shows that heat transfer is enhanced by 213%, 268% and 339% using 30°, 45° and 60° fins. Computational results show that heat transfer is enhanced by 108%, 130%, 146% using 30°, 45° and 60° fins.展开更多
文摘Losses in turbine cascade are categorized as profile loss, secondary loss, tip clearance loss and annulus loss. Profile loss occurs due to development of boundary layer on surface of blade [1]. Increase in thickness of boundary layer and adverse pressure gradient increases profile loss. Secondary loss occurs due to turning of flow through flow passage which results in blowing of energy from pressure side to suction side. In turbine rotor blade suction surface leads and tip clearance loss occurs due to leakage of air from pressure side to suction side of the blade through tip clearance. Annulus loss occurs due to development of boundary layer on stationary row of blade. It also occurs in moving row of blade but in moving row of blades boundary layer is scraped by flow over the blades. This paper presents effects of variation of pitch-chord ratio on secondary loss.
文摘Fins are used for enhancement of heat transfer. Triangular fins are arranged in form of nozzle and heat transfer coefficient is calculated. Angle of taper of nozzle is changed i.e. angles of triangles are varied and then heat transfer coefficient is calculated. Total finned area of all fins is almost the same. Number of fins and orientation of fins are different. In this study to calculate heat transfer coefficient of unfinned area open channel is considered where density and pressure are constant. This study shows that heat transfer is enhanced by 213%, 268% and 339% using 30°, 45° and 60° fins. Computational results show that heat transfer is enhanced by 108%, 130%, 146% using 30°, 45° and 60° fins.
