The concave-wall jet was formed in the vertical cylinder separator with inlet baffle component.The effect of curvature of radial baffle on the jet flow in the separator was investigated by the experiment of concentrat...The concave-wall jet was formed in the vertical cylinder separator with inlet baffle component.The effect of curvature of radial baffle on the jet flow in the separator was investigated by the experiment of concentration and the numerical simulation of species transport.The results show that the concave-wall jet was confined within the narrow region near the concave-wall and the flow disturbance in the center of separator was weakened.The distribution of concentration and the flow region of wall jet depended on the curvature of radial baffle(K).Compared with the turbulent intensity of the plate baffle(K=0),that of concave baffle(K=2)reduced by 6.1%and the turbulent intensity of convex baffle(K=-2)increased by 13.5%.The best flow stability was obtained by the concave baffle because the baffle outlet was similar to convergent nozzle.The outlet convergent angle was between 0°and 19.5°when 0≤K≤2.The secondary vortices were caused by the tangential velocity irregularity on the cross-section of two axial baffles in the separator with convex baffle.The baffle with K≥0 was more suitable in separator inlet than that with K<0.展开更多
The wing tip vortex has a great similarity with the swirling jets.Since these are generated of a simpler and more economic form in a laboratory,it is relevant to determine which the best method is for the generation o...The wing tip vortex has a great similarity with the swirling jets.Since these are generated of a simpler and more economic form in a laboratory,it is relevant to determine which the best method is for the generation of the swirling jet.In this paper,the velocity distribution obtained experimentally with the method of generation here proposed,which consists of the employment of an axial fan without stators,is compared with the velocity distribution of swirling jets generated with three different methods.It is observed that the velocity distribution obtained with the proposed method is similar with one of the methods found in the references,which uses fixed blades guides at the entry of the pipe.The proposed method is suitable for the generation of the swirling jet and it is considered that it is simpler and more economic to use blades fixed guides.展开更多
Shear sensitive liquid crystal coating (SSLCC) can measure surface shear stress vector distribution efficiently with a high spa-tial resolution. The purpose of the present paper is to modify and extend the surface she...Shear sensitive liquid crystal coating (SSLCC) can measure surface shear stress vector distribution efficiently with a high spa-tial resolution. The purpose of the present paper is to modify and extend the surface shear stress measurement technique de-termined by Reda et al. to wind tunnel studies. All the facilities employed in the technique are very common and simple. The measurement technique is applied to surface flow beneath a tangential jet and surface flow in a turbulence wedge generated by a small cylinder in windtunnel flow. Spatially resolved shear stresses over planar surface are obtained, although the magnitude is not fully calibrated.展开更多
A previously determined surface shear stress measurement technique using shear-sensitive liquid crystal (SSLC) coating is extended for use in wind tunnel-like conditions. Simple and common everyday equipment is used i...A previously determined surface shear stress measurement technique using shear-sensitive liquid crystal (SSLC) coating is extended for use in wind tunnel-like conditions. Simple and common everyday equipment is used in the measurement; in particular a tungsten halogen light bulb provides illumination. The color change characteristics of two SSLC mixtures, BCN192 and BN/ R50C, are investigated. BCN/192 is found sensitive to both magnitude and direction of the shear stress at different shear stress levels with little noise, and is suitable for surface shear stress distribution measurements. The spatial shear stress vector distribution beneath a tangential jet is obtained using BCN/192, although the magnitude is not fully calibrated. BN/R50C is found to be sensitive to shear stress magnitude, but only slightly sensitive to shear stress direction at both low and high levels. Moreover, jumps in the reflected hue are found when the viewing orientation is perpendicular to the shear stress direction. These characteristics render the use of BN/R50C for surface shear stress measurement difficult.展开更多
基金supported by the National Natural Science Foun-dations of China(51506133)Natural Science Foundation of Liaon-ing Province of China(2019ZD0078,2019MS259)Key projects of Liaoning Province education department of China(LZ2019001).
文摘The concave-wall jet was formed in the vertical cylinder separator with inlet baffle component.The effect of curvature of radial baffle on the jet flow in the separator was investigated by the experiment of concentration and the numerical simulation of species transport.The results show that the concave-wall jet was confined within the narrow region near the concave-wall and the flow disturbance in the center of separator was weakened.The distribution of concentration and the flow region of wall jet depended on the curvature of radial baffle(K).Compared with the turbulent intensity of the plate baffle(K=0),that of concave baffle(K=2)reduced by 6.1%and the turbulent intensity of convex baffle(K=-2)increased by 13.5%.The best flow stability was obtained by the concave baffle because the baffle outlet was similar to convergent nozzle.The outlet convergent angle was between 0°and 19.5°when 0≤K≤2.The secondary vortices were caused by the tangential velocity irregularity on the cross-section of two axial baffles in the separator with convex baffle.The baffle with K≥0 was more suitable in separator inlet than that with K<0.
文摘The wing tip vortex has a great similarity with the swirling jets.Since these are generated of a simpler and more economic form in a laboratory,it is relevant to determine which the best method is for the generation of the swirling jet.In this paper,the velocity distribution obtained experimentally with the method of generation here proposed,which consists of the employment of an axial fan without stators,is compared with the velocity distribution of swirling jets generated with three different methods.It is observed that the velocity distribution obtained with the proposed method is similar with one of the methods found in the references,which uses fixed blades guides at the entry of the pipe.The proposed method is suitable for the generation of the swirling jet and it is considered that it is simpler and more economic to use blades fixed guides.
基金supported by the Doctorate Creation Foundation of North-western Polytechnical University (Grant No. CX200902)
文摘Shear sensitive liquid crystal coating (SSLCC) can measure surface shear stress vector distribution efficiently with a high spa-tial resolution. The purpose of the present paper is to modify and extend the surface shear stress measurement technique de-termined by Reda et al. to wind tunnel studies. All the facilities employed in the technique are very common and simple. The measurement technique is applied to surface flow beneath a tangential jet and surface flow in a turbulence wedge generated by a small cylinder in windtunnel flow. Spatially resolved shear stresses over planar surface are obtained, although the magnitude is not fully calibrated.
基金supported by the Doctorate Creation Foundation of Northwestern Polytechnical University (CX200902)
文摘A previously determined surface shear stress measurement technique using shear-sensitive liquid crystal (SSLC) coating is extended for use in wind tunnel-like conditions. Simple and common everyday equipment is used in the measurement; in particular a tungsten halogen light bulb provides illumination. The color change characteristics of two SSLC mixtures, BCN192 and BN/ R50C, are investigated. BCN/192 is found sensitive to both magnitude and direction of the shear stress at different shear stress levels with little noise, and is suitable for surface shear stress distribution measurements. The spatial shear stress vector distribution beneath a tangential jet is obtained using BCN/192, although the magnitude is not fully calibrated. BN/R50C is found to be sensitive to shear stress magnitude, but only slightly sensitive to shear stress direction at both low and high levels. Moreover, jumps in the reflected hue are found when the viewing orientation is perpendicular to the shear stress direction. These characteristics render the use of BN/R50C for surface shear stress measurement difficult.
