The principle and method for measuring the wall thickness of transparent tube are presented.The measurement is based on total-refection vanishing light. The transmittance of transparent tube in the parallel light is s...The principle and method for measuring the wall thickness of transparent tube are presented.The measurement is based on total-refection vanishing light. The transmittance of transparent tube in the parallel light is studied. The critical conditions of total--reflection are discussed.展开更多
In this paper, the outline of the Mach 4 supersonic wind tunnel for the investigation of the supersonic internal flows in ducts was firstly described. Secondly, the location, structure and characteristics of the Mach ...In this paper, the outline of the Mach 4 supersonic wind tunnel for the investigation of the supersonic internal flows in ducts was firstly described. Secondly, the location, structure and characteristics of the Mach 2 and Mach 4 pseudo-shock waves in a square duct were investigated by color schlieren photographs and duct wall pressure fluctuation measurements. Finally, the wall shear stress distributions on the side, top and bottom walls of the square duct with the Mach 4 pseudo-shock wave were investigated qualitatively by the shear stress-sensitive liquid crystal visualization method. The side wall boundary layer separation region under the first shock is narrow near the top wall, while the side wall boundary layer separation region under the first shock is very wide near the bottom wall.展开更多
The heat conduction equation is solved in this paper under specific boundary conditions.The coefficients of the obtained distribution equation are simplified with the piecewise integral method.Then the associated mode...The heat conduction equation is solved in this paper under specific boundary conditions.The coefficients of the obtained distribution equation are simplified with the piecewise integral method.Then the associated model for the cylindrical thermal equipment is established.The relationship of the surface temperatures,the material properties and the inner wall state of the cylindrical thermal equipment is described in the associated model.This model is applied to the inner wall running state monitoring of the main pipe.A multi-channel distributed optical fiber temperature measurement system is designed to acquire the external surface temperatures of the main pipe.Then the associated model can be used to analyze the surface temperature data of the main pipe.The location and the physical dimension of the inner wall defect can be got.Therefore,the inner wall defect monitoring of the main pipe can be realized.The feasibility of this method is verified by experiment.This method also provides a theoretical basis for the real-time monitoring of the main pipe’s internal state.展开更多
文摘The principle and method for measuring the wall thickness of transparent tube are presented.The measurement is based on total-refection vanishing light. The transmittance of transparent tube in the parallel light is studied. The critical conditions of total--reflection are discussed.
文摘In this paper, the outline of the Mach 4 supersonic wind tunnel for the investigation of the supersonic internal flows in ducts was firstly described. Secondly, the location, structure and characteristics of the Mach 2 and Mach 4 pseudo-shock waves in a square duct were investigated by color schlieren photographs and duct wall pressure fluctuation measurements. Finally, the wall shear stress distributions on the side, top and bottom walls of the square duct with the Mach 4 pseudo-shock wave were investigated qualitatively by the shear stress-sensitive liquid crystal visualization method. The side wall boundary layer separation region under the first shock is narrow near the top wall, while the side wall boundary layer separation region under the first shock is very wide near the bottom wall.
基金supported by the Special Foundation for State Major Basic Research Program of China(Grant No.2011ZX04002-101)
文摘The heat conduction equation is solved in this paper under specific boundary conditions.The coefficients of the obtained distribution equation are simplified with the piecewise integral method.Then the associated model for the cylindrical thermal equipment is established.The relationship of the surface temperatures,the material properties and the inner wall state of the cylindrical thermal equipment is described in the associated model.This model is applied to the inner wall running state monitoring of the main pipe.A multi-channel distributed optical fiber temperature measurement system is designed to acquire the external surface temperatures of the main pipe.Then the associated model can be used to analyze the surface temperature data of the main pipe.The location and the physical dimension of the inner wall defect can be got.Therefore,the inner wall defect monitoring of the main pipe can be realized.The feasibility of this method is verified by experiment.This method also provides a theoretical basis for the real-time monitoring of the main pipe’s internal state.
