In some of the coalfields in India, coal seams are only developed but no extraction of pillars is possible due to the presence of surface or sub-surface structures and also non-availability of stowing materials which ...In some of the coalfields in India, coal seams are only developed but no extraction of pillars is possible due to the presence of surface or sub-surface structures and also non-availability of stowing materials which leads to huge amounts of coal being locked-up underground. Spontaneous heating and fire, accumulation of poisonous gases, severe stability issues leading to unsafe workings and environmental hazards are the major problems associated with the developed coal pillars. So, there is a pressing need for a technology for the mining industry to extract the huge amount of coal locked-up under different constraints. In this study, the locked-up coal is proposed to be extracted by artificially strengthening the rib pillars. The detailed comparative study is carried out to know the increase of extraction percentage of locked-up coal by strengthening the rib pillars with FRP. Extraction methodology is designed and studied through numerical modelling for its stability analysis to evaluate its suitability of application in underground.展开更多
Impingement heat transfer from the rib roughened surface within 2 dimensional arrays of circular jet has been experimentally investigated.This investigation is intended here to include the flow and the heat transfer c...Impingement heat transfer from the rib roughened surface within 2 dimensional arrays of circular jet has been experimentally investigated.This investigation is intended here to include the flow and the heat transfer characteristics of the jet impinging on the rib roughened surface with initial crossflow for simulating the impingement cooling midchord region of the gas turbine aerofoils in case where an initial crossflow is presented.The study covered the ranges of crossflow G_(c)/G_(j)=0~0.55 under the conditions of Re_(j)=8000~11000 and Z/d=1.5~3.0 for smooth and rib roughened surfaces.The test results show that the impingement heat transfer from the rib roughened surface is considerably affected by the initial crossflow rate.The existence of the initial crossflow will improve the efficiency of the impingement heat transfer from the rib roughened surface within arrays of circular jet compared with that from the smooth surface.展开更多
基金a part of the 12th Five Year Plan Project(No.ESC 0105),acronymed as‘‘De Coal Art”
文摘In some of the coalfields in India, coal seams are only developed but no extraction of pillars is possible due to the presence of surface or sub-surface structures and also non-availability of stowing materials which leads to huge amounts of coal being locked-up underground. Spontaneous heating and fire, accumulation of poisonous gases, severe stability issues leading to unsafe workings and environmental hazards are the major problems associated with the developed coal pillars. So, there is a pressing need for a technology for the mining industry to extract the huge amount of coal locked-up under different constraints. In this study, the locked-up coal is proposed to be extracted by artificially strengthening the rib pillars. The detailed comparative study is carried out to know the increase of extraction percentage of locked-up coal by strengthening the rib pillars with FRP. Extraction methodology is designed and studied through numerical modelling for its stability analysis to evaluate its suitability of application in underground.
文摘Impingement heat transfer from the rib roughened surface within 2 dimensional arrays of circular jet has been experimentally investigated.This investigation is intended here to include the flow and the heat transfer characteristics of the jet impinging on the rib roughened surface with initial crossflow for simulating the impingement cooling midchord region of the gas turbine aerofoils in case where an initial crossflow is presented.The study covered the ranges of crossflow G_(c)/G_(j)=0~0.55 under the conditions of Re_(j)=8000~11000 and Z/d=1.5~3.0 for smooth and rib roughened surfaces.The test results show that the impingement heat transfer from the rib roughened surface is considerably affected by the initial crossflow rate.The existence of the initial crossflow will improve the efficiency of the impingement heat transfer from the rib roughened surface within arrays of circular jet compared with that from the smooth surface.
