To realize a stable addition of foaming agent used for foam technology, a new adding method using the jet cavitation was introduced, and its performance was investigated experimentally under different operating condit...To realize a stable addition of foaming agent used for foam technology, a new adding method using the jet cavitation was introduced, and its performance was investigated experimentally under different operating conditions. Experimental results show that the bubble region in the jet device has a constant vapor pressure, which creates a good condition for liquid absorption, while it shrinks with increasing outlet pressure. The liquid absorption amount keeps unchanged when the outlet pressure is lower than a critical value. The critical outlet pressure increases by 40% with decreasing cavitation absorption amount, which is especially suitable for mini-flow quantitative addition of foaming agent used for foam dust suppression. Its effectiveness on suppressing mine dust was evaluated in a heading face of underground coal mines. Field application indicates that the reliable and simple foaming system adopting the new adding method makes a marked dust suppression effect. The working environment of heading face is significantly improved, ensuring the safe tunneling and personal security.展开更多
This paper performs a numerical simulation of three-dimensional flow field in a centrifugal compressor with long inlet and outlet pipes using CFX software.By arranging virtual probes at different positions in both inl...This paper performs a numerical simulation of three-dimensional flow field in a centrifugal compressor with long inlet and outlet pipes using CFX software.By arranging virtual probes at different positions in both inlet and outlet planes,the aerodynamic performance of the centrifugal compressor is measured and compared with each other.Then effects of measuring positions on measurement results are discussed.The results show that it will generate notable measuring errors of the pressure ratio and efficiency if the inlet total pressure is measured using a single-point probe.The inlet total pressure data can be accurate when they are measured using a 3-point rake.The outlet total pressure and total temperature data can not be accurate if they are respectively measured at one circumferential position even using a multi-point rake.Increasing tangential measuring positions at the outlet is effective to improve the test accuracy.When the outlet total pressure and total temperature are respectively measured at 3 tangential positions,the data can be almost accurate.展开更多
文摘为研究闭式试验台试验过程中水泵装置模型各参数的变化规律和特征,采用物理模拟试验的方法,在水泵立式试验台上对某泵站模型泵进行性能试验.通过在稳定转速的条件下逐步减小流量,同时采集装置进出口前后即试验台上下游处的平均压力以及水泵运行时其他工况各参数,分析了试验过程中水泵装置模型的进出口前后的压力及其轴功率变化过程,探讨了试验系统在向稳定工况过渡过程中,水泵及系统内部各工况的变化情况.试验结果表明:在整个过渡过程中,水泵进口前的压力波动不大,相对稳定;出口后的压力在初始阶段呈上升趋势波动,波动幅度较大,经过一段时间后,也趋于相对稳定;轴功率的变化与出口后的压力波动类似,初始阶段波动较大,但变化明显,随着时间的延续,逐渐趋于稳定;过渡过程持续时间大于90 s.
基金Project(51474216)supported by the National Natural Science Foundation of ChinaProject supported by the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions,ChinaProject(2012DXS02)supported by the Fundamental Research Funds for the Central Universities,China
文摘To realize a stable addition of foaming agent used for foam technology, a new adding method using the jet cavitation was introduced, and its performance was investigated experimentally under different operating conditions. Experimental results show that the bubble region in the jet device has a constant vapor pressure, which creates a good condition for liquid absorption, while it shrinks with increasing outlet pressure. The liquid absorption amount keeps unchanged when the outlet pressure is lower than a critical value. The critical outlet pressure increases by 40% with decreasing cavitation absorption amount, which is especially suitable for mini-flow quantitative addition of foaming agent used for foam dust suppression. Its effectiveness on suppressing mine dust was evaluated in a heading face of underground coal mines. Field application indicates that the reliable and simple foaming system adopting the new adding method makes a marked dust suppression effect. The working environment of heading face is significantly improved, ensuring the safe tunneling and personal security.
基金funded by Chinese Key Laboratory Fund,Grant No.9140C3310040705the National Natural Science Foundation of China,Grant No.50776004+1 种基金supported by the 111 Project,No.B07009973 Project,No.2007CB210103
文摘This paper performs a numerical simulation of three-dimensional flow field in a centrifugal compressor with long inlet and outlet pipes using CFX software.By arranging virtual probes at different positions in both inlet and outlet planes,the aerodynamic performance of the centrifugal compressor is measured and compared with each other.Then effects of measuring positions on measurement results are discussed.The results show that it will generate notable measuring errors of the pressure ratio and efficiency if the inlet total pressure is measured using a single-point probe.The inlet total pressure data can be accurate when they are measured using a 3-point rake.The outlet total pressure and total temperature data can not be accurate if they are respectively measured at one circumferential position even using a multi-point rake.Increasing tangential measuring positions at the outlet is effective to improve the test accuracy.When the outlet total pressure and total temperature are respectively measured at 3 tangential positions,the data can be almost accurate.
