A design of a rotating condenser is suggested. The maximum radius under the effect of rotation is estimated analytically .It is found that it decreases with the angular velocity. This in turn increases the rate of swe...A design of a rotating condenser is suggested. The maximum radius under the effect of rotation is estimated analytically .It is found that it decreases with the angular velocity. This in turn increases the rate of sweeping the surface by departing droplets. The appearance of droplets with smaller radii will be predominant. These small droplets offer small thermal resistances, thus enhancing heat transfer through the condenser surface. It is found also that the maximum radius is a function of the distance from the axis of the rotating condenser. Thus the value of the maximum radius under rotation is not unique. This in turn makes the heat flux through the condenser surface not to be uniform.展开更多
The valuation of the hydraulic performance of a centrifugal pump with pre-whirl regulation of the inlet guide vanes was studied experimentally by varying the pre-whirl angle from -60° to 60° with distances b...The valuation of the hydraulic performance of a centrifugal pump with pre-whirl regulation of the inlet guide vanes was studied experimentally by varying the pre-whirl angle from -60° to 60° with distances between the inlet guide vanes and the impeller inlet of 280 mm, 380 mm and 460 mm. The efficiency-flow curves and the characteristic curves were obtained for the pump for various operation conditions. The experiment results demonstrated that the pre-whirl regulation widened the high efficiency zone and improved the hydraulic performance for off-design conditions with the proper pre-whirl angle. The axial distance between the inlet guide vanes and the impeller inlet influenced the pre-whirl regulation effect of the inlet guide vanes with the best pre-whirl regulation effect obtained for an axial distance of 380 mm. These results showed that an appropriate axial distance between the inlet guide vanes and the impeller inlet can improve the fluid flow at the impeller entrance with pre-whirl regulation for centrifugal pumps.展开更多
The ventilators have been vividly called ＂the lungs of mine＂. The rotating blades are the core parts of a ventilator, they can influence the safety and reliability of the ventilator. This paper will use the tip-timi...The ventilators have been vividly called ＂the lungs of mine＂. The rotating blades are the core parts of a ventilator, they can influence the safety and reliability of the ventilator. This paper will use the tip-timing method based on the fiber Bragg grating magnetically coupling sensor to study and analyze the ventilator blade vibration, in order to realize long-distance and non-contact real-time online safety monitoring of blade vibration. Compared with the electronic sensorand fiber intensity reflective sensor, the fiber grating coupling magnetic sensor has such advantages as explosion-proof, working at harsh environment with humid air, dust and greasy dirt, capable of achieving long-distance signal transmission, and joining easily with other fiber Bragg grating sensors to form a network in order to achieve multi-parameter distributed online monitoring.展开更多
文摘A design of a rotating condenser is suggested. The maximum radius under the effect of rotation is estimated analytically .It is found that it decreases with the angular velocity. This in turn increases the rate of sweeping the surface by departing droplets. The appearance of droplets with smaller radii will be predominant. These small droplets offer small thermal resistances, thus enhancing heat transfer through the condenser surface. It is found also that the maximum radius is a function of the distance from the axis of the rotating condenser. Thus the value of the maximum radius under rotation is not unique. This in turn makes the heat flux through the condenser surface not to be uniform.
基金supported by the National Natural Science Foundation of China (Grant No. 51176088)the National Basic Research Program of China ("973" Project) (Grant No. 2009CB724304) the General Financial Grant from the China Postdoctoral Science Foundation (Grant No. 2011M500315)
文摘The valuation of the hydraulic performance of a centrifugal pump with pre-whirl regulation of the inlet guide vanes was studied experimentally by varying the pre-whirl angle from -60° to 60° with distances between the inlet guide vanes and the impeller inlet of 280 mm, 380 mm and 460 mm. The efficiency-flow curves and the characteristic curves were obtained for the pump for various operation conditions. The experiment results demonstrated that the pre-whirl regulation widened the high efficiency zone and improved the hydraulic performance for off-design conditions with the proper pre-whirl angle. The axial distance between the inlet guide vanes and the impeller inlet influenced the pre-whirl regulation effect of the inlet guide vanes with the best pre-whirl regulation effect obtained for an axial distance of 380 mm. These results showed that an appropriate axial distance between the inlet guide vanes and the impeller inlet can improve the fluid flow at the impeller entrance with pre-whirl regulation for centrifugal pumps.
文摘The ventilators have been vividly called ＂the lungs of mine＂. The rotating blades are the core parts of a ventilator, they can influence the safety and reliability of the ventilator. This paper will use the tip-timing method based on the fiber Bragg grating magnetically coupling sensor to study and analyze the ventilator blade vibration, in order to realize long-distance and non-contact real-time online safety monitoring of blade vibration. Compared with the electronic sensorand fiber intensity reflective sensor, the fiber grating coupling magnetic sensor has such advantages as explosion-proof, working at harsh environment with humid air, dust and greasy dirt, capable of achieving long-distance signal transmission, and joining easily with other fiber Bragg grating sensors to form a network in order to achieve multi-parameter distributed online monitoring.
