Mini centrifugal pumps having a diameter smaller than lOOmm are employed in many fields. But the design method for the mini centrifugal pump is not established because the internal flow condition for these small-sized...Mini centrifugal pumps having a diameter smaller than lOOmm are employed in many fields. But the design method for the mini centrifugal pump is not established because the internal flow condition for these small-sized fluid machines is not clarified and conventional theory is not suitable for small-sized pumps. Therefore, mini cen- trifugal pumps with simple structure were investigated by this research. Splitter blades were adopted in this re- search to improve the performance and the internal flow condition of mini centrifugal pump which had large blade outlet angle. The original impeller without the splitter blades and the impeller with the splitter blades were prepared for experiment. The performance tests are conducted with these rotors in order to investigate the effect of the splitter blades on performance and internal flow condition of mini centrifugal pump. On the other hand, a three dimensional unsteady numerical flow analysis was conducted to investigate the change of the internal flow according to the rotor rotation. It is clarified from the experimental results that the performance of the mini cen- trifugal pump is improved by the splitter blades. The blade-to-blade low velocity region was suppressed in the case with the splitter blades. In addition to that, the unsteady flows near the volute casing tongue were suppressed due to the splitter blades. In the present paper, the performance of the mini centrifugal pump is shown and the un- steady flow condition is clarified with the results of the numerical flow analysis. Furthermore, the effects of the splitter blades on the performance and the unsteady internal flow condition are investigated.展开更多
Mini turbo-pumps having a diameter smaller than 100mm are employed in many fields;automobile radiator pump,ventricular assist pump,cooling pump for electric devices,washing machine pump and so on.Further,the needs for...Mini turbo-pumps having a diameter smaller than 100mm are employed in many fields;automobile radiator pump,ventricular assist pump,cooling pump for electric devices,washing machine pump and so on.Further,the needs for mini turbo-pumps would become larger with the increase of the application of it for electrical machines.It is desirable that the mini turbo-pump design is as simple as possible due to restriction to make precise manufactures.But the design method for the mini turbo-pump is not established because the internal flow condition for these small-sized fluid machineries is not clarified and conventional theory is not conductive for small-sized pumps.Three types of rotors with different outlet angles are prepared for an experiment and a numerical analysis.The performance tests are conducted with these rotors in order to investigate the effect of the blade outlet angle on performance and internal flow condition of mini turbo-pumps.It is clarified from the experimental results that head of the mini turbo-pump increases and maximum efficiency flow rate shifts to larger flow rate according to the increase of the blade outlet angle,however the maximum efficiency decreases with the increase of it.In the present paper,the performance of the mini turbo-pump is shown and the internal flow conditions are clarified with the results of the experiment and the numerical flow analysis.Furthermore,the effects of the blade outlet angle on the performance are investigated and high performance design with simple structure for the mini turbo-pump would be considered.展开更多
To unravel the intricacies of two-phase gas-liquid flow characteristics and heat transfer behavior,an array mini-channel gravity plate heat pipe(AMGPHP)is proposed in this work,which allows for observing the internal ...To unravel the intricacies of two-phase gas-liquid flow characteristics and heat transfer behavior,an array mini-channel gravity plate heat pipe(AMGPHP)is proposed in this work,which allows for observing the internal changes in the state of the working fluids.The flow patterns such as pool flow,columnar flow,and slug flow,are experimentally explored and analyzed in detail.It is found that the optimal volume fill ratio is 20%by utilizing start-up time and thermal resistance as performance evaluation metrics.With this fill ratio,a medium optimization strategy by blending ethanol within R141b is proposed and evaluated.In comparison to pure working fluids,the heat transfer performance of AMGFHP in the binary fluid has been significantly augmented due to temperature and concentration shifts resulting from disparate boiling points.Under the 10%volume fraction ethanol blending condition,the equivalent thermal conductivity of the heat pipe is dramatically elevated,with a value of 3110 W/(m·℃),along with the reduction of the minimum start-up power to 4 W.In general,applying such a medium to heat pipes has considerable potential in practical applications.展开更多
Experimental studies on the flow pattern and the pressure gradient of gas-liquid co-current two-phase flow in a mini-channel were conducted.The test section was a transparent circular channel of 1.6 mm inner diameter....Experimental studies on the flow pattern and the pressure gradient of gas-liquid co-current two-phase flow in a mini-channel were conducted.The test section was a transparent circular channel of 1.6 mm inner diameter.The working fluids were air and water.The superficial velocities of gas and liquid were in the range of 0.025-66.300 m/s and 0.033-4.935 m/s,respectively.In the present work,the flow pattern and the pressure gradient data were obtained by analyzing the flow images captured by a high-speed camera,and by using the pressure transducer,respectively.As a result,it was found that (1) the obtained flow patterns were bubbly,plug,slug-annular,annular,and chum flows,(2) new experimental correlations on the bubble and plug lengths were proposed,whereas the lengths are the function of the homogeneous void fraction,(3) both gas and liquid superficial velocities affect proportionally to the pressure gradient,whereas it increases with the increase both of JG,JL.In addition,the obtained flow patterns are in a good agreement with that of the available flow pattern maps in the open literatures,such as,Triplett et al.(1999) and Chung and Kawaji (2004).展开更多
以生产小直径热轧精密无缝钢管为背景,详细介绍了Φ114 mm PCM短流程精密热连轧无缝钢管生产线的设备选型和工艺特点,以及该生产线的实际生产情况。实际生产结果表明:采用3机架二辊连轧管机组生产小批量热轧精密无缝钢管,其在产品质量...以生产小直径热轧精密无缝钢管为背景,详细介绍了Φ114 mm PCM短流程精密热连轧无缝钢管生产线的设备选型和工艺特点,以及该生产线的实际生产情况。实际生产结果表明:采用3机架二辊连轧管机组生产小批量热轧精密无缝钢管,其在产品质量、生产成本、节能环保和投资运营等方面具有明显的优势,生产组织灵活,设备易于掌握和达产。展开更多
文摘Mini centrifugal pumps having a diameter smaller than lOOmm are employed in many fields. But the design method for the mini centrifugal pump is not established because the internal flow condition for these small-sized fluid machines is not clarified and conventional theory is not suitable for small-sized pumps. Therefore, mini cen- trifugal pumps with simple structure were investigated by this research. Splitter blades were adopted in this re- search to improve the performance and the internal flow condition of mini centrifugal pump which had large blade outlet angle. The original impeller without the splitter blades and the impeller with the splitter blades were prepared for experiment. The performance tests are conducted with these rotors in order to investigate the effect of the splitter blades on performance and internal flow condition of mini centrifugal pump. On the other hand, a three dimensional unsteady numerical flow analysis was conducted to investigate the change of the internal flow according to the rotor rotation. It is clarified from the experimental results that the performance of the mini cen- trifugal pump is improved by the splitter blades. The blade-to-blade low velocity region was suppressed in the case with the splitter blades. In addition to that, the unsteady flows near the volute casing tongue were suppressed due to the splitter blades. In the present paper, the performance of the mini centrifugal pump is shown and the un- steady flow condition is clarified with the results of the numerical flow analysis. Furthermore, the effects of the splitter blades on the performance and the unsteady internal flow condition are investigated.
文摘Mini turbo-pumps having a diameter smaller than 100mm are employed in many fields;automobile radiator pump,ventricular assist pump,cooling pump for electric devices,washing machine pump and so on.Further,the needs for mini turbo-pumps would become larger with the increase of the application of it for electrical machines.It is desirable that the mini turbo-pump design is as simple as possible due to restriction to make precise manufactures.But the design method for the mini turbo-pump is not established because the internal flow condition for these small-sized fluid machineries is not clarified and conventional theory is not conductive for small-sized pumps.Three types of rotors with different outlet angles are prepared for an experiment and a numerical analysis.The performance tests are conducted with these rotors in order to investigate the effect of the blade outlet angle on performance and internal flow condition of mini turbo-pumps.It is clarified from the experimental results that head of the mini turbo-pump increases and maximum efficiency flow rate shifts to larger flow rate according to the increase of the blade outlet angle,however the maximum efficiency decreases with the increase of it.In the present paper,the performance of the mini turbo-pump is shown and the internal flow conditions are clarified with the results of the experiment and the numerical flow analysis.Furthermore,the effects of the blade outlet angle on the performance are investigated and high performance design with simple structure for the mini turbo-pump would be considered.
基金supported by Industrial Foresight Project in Yangzhou City(No.YZ2021002)Transformation of Scientific and Technical Achievements Project in Yangzhou City(No.YZ2021121)National Key Research and Development Plan of China(No.2018YFA0702300)。
文摘To unravel the intricacies of two-phase gas-liquid flow characteristics and heat transfer behavior,an array mini-channel gravity plate heat pipe(AMGPHP)is proposed in this work,which allows for observing the internal changes in the state of the working fluids.The flow patterns such as pool flow,columnar flow,and slug flow,are experimentally explored and analyzed in detail.It is found that the optimal volume fill ratio is 20%by utilizing start-up time and thermal resistance as performance evaluation metrics.With this fill ratio,a medium optimization strategy by blending ethanol within R141b is proposed and evaluated.In comparison to pure working fluids,the heat transfer performance of AMGFHP in the binary fluid has been significantly augmented due to temperature and concentration shifts resulting from disparate boiling points.Under the 10%volume fraction ethanol blending condition,the equivalent thermal conductivity of the heat pipe is dramatically elevated,with a value of 3110 W/(m·℃),along with the reduction of the minimum start-up power to 4 W.In general,applying such a medium to heat pipes has considerable potential in practical applications.
文摘Experimental studies on the flow pattern and the pressure gradient of gas-liquid co-current two-phase flow in a mini-channel were conducted.The test section was a transparent circular channel of 1.6 mm inner diameter.The working fluids were air and water.The superficial velocities of gas and liquid were in the range of 0.025-66.300 m/s and 0.033-4.935 m/s,respectively.In the present work,the flow pattern and the pressure gradient data were obtained by analyzing the flow images captured by a high-speed camera,and by using the pressure transducer,respectively.As a result,it was found that (1) the obtained flow patterns were bubbly,plug,slug-annular,annular,and chum flows,(2) new experimental correlations on the bubble and plug lengths were proposed,whereas the lengths are the function of the homogeneous void fraction,(3) both gas and liquid superficial velocities affect proportionally to the pressure gradient,whereas it increases with the increase both of JG,JL.In addition,the obtained flow patterns are in a good agreement with that of the available flow pattern maps in the open literatures,such as,Triplett et al.(1999) and Chung and Kawaji (2004).
文摘以生产小直径热轧精密无缝钢管为背景,详细介绍了Φ114 mm PCM短流程精密热连轧无缝钢管生产线的设备选型和工艺特点,以及该生产线的实际生产情况。实际生产结果表明:采用3机架二辊连轧管机组生产小批量热轧精密无缝钢管,其在产品质量、生产成本、节能环保和投资运营等方面具有明显的优势,生产组织灵活,设备易于掌握和达产。
