J-그루브에 의한 인듀서의 캐비테이션 억제

쿠로카와준이치(Junichi Kurokawa),최영도(Young-Do Choi) 한국유체기계학회 2005 유체기계 연구개발 발표회 논문집 Vol.- No.-

Cavitation is the most serious problem caused in developing high-speed turbopump, and use of an inducer is often made to avoid cavitation in main impeller. Thus, the inducer always operates under the worst condition of cavitation. If it could be possible to control and suppress cavitation in the inducer by some new device, it would also be possible to suppress cavitation occurring in all types of pumps. The purpose of our present study is to develop a new effective method of controlling and suppressing cavitation in an inducer using shallow grooves, named as "J-Groove". J-Groove is installed on the casing wall near the blade tip to use the pressure difference between high pressure region and low pressure region in the axial direction at the inlet of the inducer. The results show that proper combination of backward-swept inducer with J-Groove improves suction performance of turbopump remarkably in the range of partial flow rate as well as designed flow rate. The rotating backflow cavitation occurring in the range of low flow rate and the cavitation surge occurring in the vicinity of the best efficiency point can be almost fully suppressed by installing J-Groove.

원심펌프의 축추력 제어법에 관한 연구

최영도,쿠로카와준이치 한국유체기계학회 2007 한국유체기계학회 논문집 Vol.10 No.4

In order to control and balance axial thrust of turbo machine, many types of balancing devices are used but most of them are complicated and sometimes cause troubles. In this study, a very simple device of using shallow grooves mounted on a casing wall, known as “J-Groove”, is proposed and studied experimentally and theoretically. The result shows that 70% of axial thrust in an industrial 4-stage centrifugal pump can be reduced at the best efficiency point. Moreover, the analytical method of “interfered gap flow” is established and a simple formula which can determine the optimum dimension of groove and its location is proposed.* 한국해양대학교 산학협력단

J-그루브를 이용한 인듀서의 캐비테이션 억제에 관한 연구

최영도,쿠로카와준이치 대한기계학회 2005 大韓機械學會論文集B Vol.29 No.11

극저비속도 원심펌프의 불안정성능개선 및 소형화에 관한 연구

최영도,쿠로카와준이치 한국유체기계학회 2007 한국유체기계학회 논문집 Vol.10 No.4

The ratio of disk friction loss in a centrifugal pump is very large for the total pump loss in the range of very low specific speed. Therefore, impeller radius should be shortened to increase the pump efficiency because the disk friction loss is proportional to the fifth power of impeller radius. In order to compensate the decreased head by the shortened impeller radius, vane angle at impeller outlet should be increased. However, as the vane angle at impeller outlet becomes larger, performance instability occurs at low flow rate regions. In this study, J-Groove is adopted to suppress the performance instability and detailed examination is performed for the influence of the J-Groove on the pump performance. The results show that J-Groove gives good effect on the suppression of performance instability. Moreover, as J-Groove increases pump head considerably, the pump size can be smaller for head requirements.* 한국해양대학교 산학협력단

극저비속도 원심펌프의 펌프성능 및 흡입성능 향상

최영도,쿠로카와준이치,Choi Young-Do,Kurokawa Junichi 한국유체기계학회 2006 한국유체기계학회 논문집 Vol.9 No.3

There are high expectations of improving the performance of a centrifugal pump in the range of very low specific speed which has been developed recently for the use instead of a conventional positive displacement pump. However, even though elaborated studies has been done for the pump intensively, the pump performance has not increased so much. Also, it is difficult to find detailed information from published literatures for suction performance of the very low specific speed centrifugal pump. Therefore, this study is aimed to improve the pump performance more and to make clear suction performance of the very low specific speed centrifugal pump. Recircular flow stopper is installed on the pump casing wall at the region of impeller outlet to improve the pump performance and J-Groove is also installed at the inlet of the pump casing for the purpose of suppressing occurrence of cavitation as well as improving pump performance. The result suggests that the simultaneous improvement of pump performance and suction performance of the very low specific speed centrifugal pump is possible by adopting optimum configuration of the recirculation flow stopper and J-Groove.

마이크로 관류수차의 상수도 관로시스템 적용에 관한 연구

최영도,쿠로카와준이치,Choi Young-Do,Kurokawa Junichi 한국유체기계학회 2006 한국유체기계학회 논문집 Vol.9 No.3

Recently, micro hydropower and it's useful utilization are taking a growing interest as a countermeasure of global worming by carbon dioxide and exhaustion of fossil fuel. The purpose of this study is to investigate the possibility of extracting micro hydropower wasted by a valve in water supply system using micro cross-flow hydraulic turbine. In order to fulfill the functions of controlling flow rate and pressure in substitute for the valve, air and water are supplied into an air suction hole which is installed on the side wall of micro cross-flow hydraulic turbine. The results show that in case of supplying a lot of air into the air suction hole, about 50% of flow rate and relatively high value of loss coefficient are controlled by the turbine. Moreover, including high possibility of applying the micro cross-flow turbine to water supply system, extended application of the turbine to the water discharge system of drainage and irrigation canal.

극저비속도 원심펌프의 펌프성능 및 흡입성능 향상

최영도,쿠로카와준이치 한국유체기계학회 2006 한국유체기계학회 논문집 Vol.9 No.6

There are high expectations of improving the performance of a centrifugal pump in the range of very low specific speed which has been developed recently for the use instead of a conventional positive displacement pump. However, even though elaborated studies has been done for the pump intensively, the pump performance has not increased so much. Also, it is difficult to find detailed information from published literatures for suction performance of the very low specific speed centrifugal pump. Therefore, this study is aimed to improve the pump performance more and to make clear suction performance of the very low specific speed centrifugal pump. Recircular flow stopper is installed on the pump casing wall at the region of impeller outlet to improve the pump performance and J-Groove is also installed at the inlet of the pump casing for the purpose of suppressing occurrence of cavitation as well as improving pump performance. The result suggests that the simultaneous improvement of pump performance and suction performance of the very low specific speed centrifugal pump is possible by adopting optimum configuration of the recirculation flow stopper and J-Groove.1. 서 론* 요코하마국립대학 대학원 공학연구원

마이크로 관류수차의 상수도 관로시스템 적용에 관한 연구

최영도,쿠로카와준이치 한국유체기계학회 2006 한국유체기계학회 논문집 Vol.9 No.6

Recently, micro hydropower and it's useful utilization are taking a growing interest as a countermeasure of global worming by carbon dioxide and exhaustion of fossil fuel. The purpose of this study is to investigate the possibility of extracting micro hydropower wasted by a valve in water supply system using micro cross-flow hydraulic turbine. In order to fulfill the functions of controlling flow rate and pressure in substitute for the valve, air and water are supplied into an air suction hole which is installed on the side wall of micro cross-flow hydraulic turbine. The results show that in case of supplying a lot of air into the air suction hole, about 50% of flow rate and relatively high value of loss coefficient are controlled by the turbine. Moreover, including high possibility of applying the micro cross-flow turbine to water supply system, extended application of the turbine to the water discharge system of drainage and irrigation canal.1. 서 론* 요코하마국립대학 대학원 공학연구원

극저비속도 원심펌프의 성능과 내부유동특성에 관한 연구

최영도,쿠로카와준이치,이영호 대한기계학회 2005 大韓機械學會論文集B Vol.29 No.7

원형케이싱이 극저비속도 원심펌프의 성능에 미치는 영향

최영도,카가와슈사쿠,쿠로카와준이치 한국유체기계학회 2006 한국유체기계학회 논문집 Vol.9 No.1

Recently, according to the trend of small size in scale and high speed in rotation of turbomachinery, very low specific speed centrifugal pump is taking a growing interest because the pump is characterized by high head and low flow rate with convenience of manufacturing and maintenance compared with conventional positive displacement pump. However, the efficiency of the very low specific speed centrifugal pump drops rapidly with the decrease of specific speed. The purpose of this study is not only to examine the influence of casing type on the performance of centrifugal pump in the range of very low specific speed but also to determine the proper casing type for the improvement of pump performance. The results show that circular casing is suitable for the centrifugal pump in the range of very low specific speed and the influence of impeller configuration on the pump performance is very small. Radial thrust in the circular and volute casings is considerably small in the range of very low specific speed.1. 서 론* 요코하마국립대학 대학원 공학연구원