船舶用小型サイドスラスタのキャビテーションに関する基礎研究

船舶用小型サイドスラスタのキャビテーションに関する基礎研究


直径49mm二重反転形小型ハイドロタービンの研究開発

直径49mm二重反転形小型ハイドロタービンの研究開発


Field Test of Contra-Rotating Small Hydroturbine

International Journal of Fluid Machinery and Systems


PIV Measurement of Flow Conditions Near Casing Tongue of Mini Centrifugal Pump


Pressure fluctuation on casing wall and investigation to tip leakage flow of contra-rotating small hydro-turbine

Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy


サイドスラスタの非定常内部流れと推力計測

サイドスラスタの非定常内部流れと推力計測


遠心作用を付加した二重反転形小型ハイドロタービンにおける後段遠心羽根車の内部流動状態


Influence of Blade Number on Performance and Internal Flow Condition of Centrifugal Pump for Low Viscous Fluid Food


Influence of Number of Blades on Performance and Internal Flow of High Head Contra-Rotating Small Hydroturbine


二重反転形ダクテッドファンに関する研究開発

二重反転形ダクテッドファンに関する研究開発


二重反転形小型ハイドロタービンの高落差設計に関する研究開発

二重反転形小型ハイドロタービンの高落差設計に関する研究開発


Study on High Pressure Design of Contra Rotating Small Hydroturbine


PIV Measurement of Internal Flow in Mini Centrifugal Pump


低粘度流体食品用遠心ポンプの羽根出口角が性能と内部流れに及ぼす影響

低粘度流体食品用遠心ポンプの羽根出口角が性能と内部流れに及ぼす影響


Investigation and Analysis of Attack Angle and Rear Flow Condition of Contra-Rotating Small Hydro-Turbine


Performance and Internal Flow of Contra-Rotating Small-Sized Cooling Fan


Study on performance of contra-rotating small hydro-turbine with thinner blade and longer front hub


Numerical Analysis of Contra-Rotating Small Hydro-Turbine with Cylinder Spoke


Internal Flow Condition between Front and Rear Rotor of Contra-Rotating Small-Sized Axial Fan at Low Flow Rate


Unsteady Flow Condition of Centrifugal Pump for Low Viscous Fluid Food


Internal Flow and Performance with Foreign Vegetable Materials in a Contra-Rotating Small Hydro-Turbine


Unsteady Flow Condition between Front and Rear Rotor of Contra-Rotating Small Sized Axial Fan


二重反転形小型ハイドロタービンの翼近傍における圧力変動

二重反転形小型ハイドロタービンの翼近傍における圧力変動


PIV Measurement of Inlet and Outlet Flow of Contra-Rotating Small-Sized Cooling Fan

Contra-rotating rotors have been adopted for some of the cooling fans to meet the demand for the high pressure and large flow rate. Therefore, it is important to clarify its inlet and outlet flows by experiments for the high performance and stable operation. PIV measurements were conducted at the design and partial flow rates. In the present paper, the inlet and outlet flow conditions of the contra-rotating small-sized cooling fan with a 40mm square casing are studied by using PIV measurement. Furthermore, improvements of the flow condition and design guideline to increase the performance were discussed based on the experimental results.

International Journal of Fluid Machinery and Systems


Performance and Flow Condition of Cross-Flow Wind Turbine with a Symmetrical Casing Having Side Boards

A cross-flow wind turbine has a high torque coefficient at a low tip speed ratio. Therefore, it is a good candidate for use as a self-starting turbine. Furthermore, it has low noise and excellent stability; therefore, it has attracted attention from the viewpoint of applications as a small wind turbine for an urban district. However, its maximum power coefficient is extremely low (10 %) as compared to that of other small wind turbines. In order to improve the performance and flow condition of the cross-flow rotor, the symmetrical casing with a nozzle and a diffuser are proposed and the experimental research with the symmetrical casing is conducted. The maximum power coefficient is obtained as Cpmax = 0.17 in the case with the casing and Cpmax=0.098 in the case without the casing. In the present study, the power characteristics of the cross-flow rotor and those of the symmetrical casing with the nozzle and diffuser are investigated. Then, the performance and internal flow patterns of the cross-flow wind turbine with the symmetrical casings are clarified. After that, the effect of the side boards set on the symmetrical casing is discussed on the basis of the analysis results.


Influence of Spoke Geometry on Performance and Internal Flow of Contra-Rotating Small-Sized Hydroturbine

二重反転形小型ハイドロタービンのスポーク形状が性能と内部流れに及ぼす影響


Internal Flow of Contra-Rotating Small-Sized Hydro Turbine at Maximum Efficiency Flow Rate

二重反転形小型ハイドロタービンの最高効率流量点における内部流れ

Small hydropower generation is one of important alternative energy, and potential of small hydropower is great. Efficiency of small hydro turbines is lower than that of large one. Then, there are demands for small hydro turbines to keep high performance. Therefore, we adopted contra-rotating rotors, which can be expected to achieve high performance. In this research, experimental apparatus of the contra-rotating small hydro turbine with 60 mm casing diameter was manufactured and performance of it was investigated by an experiment. Efficiency of the contra-rotating small hydro turbine was high in pico-hydro turbines and high efficiency could be kept in wide flow rate range. Unsteady internal flow conditions, which were difficult to measure experimentally, were shown by the numerical flow analysis. Further, pressure distributions and wake interactions with a rotor rotation were clarified. Then, a relation between the performance and unsteady internal flow condition was considered by the experimental and numerical analysis results.


Effects of eccentric vortex on internal flow and performance of a cross-flow fan

クロスフローファンの偏心渦が内部流れと性能に及ぼす影響について

In the internal flow of the cross flow fan, the formation of the eccentric vortex centered on the rotor inner periphery is well known. So far, the relationship between fan shape and performance, and the formation mechanism and behavior of the eccentric vortex have been reported. However, few studies have focused on the relevance of the fan performance and the eccentric vortex. In this paper, the structure, behavior and driving power of the eccentric vortex are investigated. Next, the effect of the eccentric vortex on the performance is considered. As a result, the following becomes apparent. The entrance flow of the cross flow fan is sucked towards the eccentric vortex indicating strong suction pressure, and therefore, the velocity at the rotor inlet becomes non-uniform in the circumferential direction. Because inlet velocity becomes fast in the tongue side which is near the eccentric vortex, the driving power of the eccentric vortex becomes large. By generating swirling flow by the change of an entrance shape and decreasing tongue side velocity by the outward centrifugal force of this turning flow, the eccentric vortex power decreases and high fan efficiency is accomplished. Finally, the high-performance design guideline of the cross flow fan by controlling the eccentric vortex is proposed.


PIV Measurement of Inlet and Outlet Flow of High Pressure and High Flow Rate Small-Sized Cooling Fan

高圧・高風量な小型冷却ファンの入口および出口流れのPIV計測

Data center has been built with spread of cloud computing. Further, electric power consumption of it is growing rapidly. High pressure and high flow rate cooling fans are used for servers in the data center and there is a strong demand to increase pressure and flow rate of it because of increase of quantity of heat from the servers. Contra-rotating rotors have been adopted for some of high pressure and high flow rate cooling fans. It is important to clarify inlet and outlet flows of it by experiments for high performance and stable operation. PIV measurements of a high pressure and high flow rate cooling fan with 40 mm square were conducted and improvements of the flow condition were discussed by the experimental results.


Study of emulsification mechanism and droplet size estimation in a homogenizer

圧力式ホモジナイザーの乳化作用と液滴径予測に関する研究

A pressure type homogenizer consists of a plunger pump, and a valve part with a narrow channel. It generates effects such as a shear, a turbulent flow and a cavitation between fluid molecules at very short time, and makes a homogeneous emulsification state. If the flow pattern in a valve can be solved in more detail, the more efficient and stabilized emulsification will be attained. However, since it is difficult to measure the size, the pressure and the flow velocity in a narrow gap space by experiment, the details of the mechanism of emulsification by s shear, a turbulent flow, a cavitation and a collision have not been clarified enough. In this research, the size of gap is first calculated from the theoretical equation assumed to be laminar flow, based on the Reynolds number of the gap flow. Next, the pressure, the flow velocity, shearing stress, etc. are calculated. Then, the emulsification mechanism of each part of the valve is clarified by expressing the droplet size as a function of the gap size, the shearing stress and the exit velocity about two kinds of original solutions in which interfacial tension differs. Furthermore, the prediction expression of droplet size obtained by the emulsification is proposed.


Internal Flow of Contra-Rotating Small Hydro-Turbine at Off-Design Flow Rates

二重反転形小型ハイドロタービンの非設計流量点における内部流れ


Internal Flow with Foreign Vegetable Materials in a Contra-Rotating Small Hydro-Turbine

植物性異物混入時における二重反転形小型ハイドロタービンの内部流れ


Unsteady Internal Flow in a Centrifugal Pump for Low Viscous Fluid Food

低粘度流体食品用遠心ポンプの非定常内部流れについて

Fluid machineries for fluid food have been used in wide variety of field i.e. transportation, filling, and improvement of quality of fluid food. Although, flow conditions of these are quite complicated because fluid food is different from water. Therefore, design method based on the internal flow conditions is not conducted. In this research, the centrifugal pump having small number of blade was used to decrease shear loss and keep wide flow passage. In previous studies, it was found that unsteady internal flow condition occurred in a test pump, but those flow phenomena were not clarified. In order to investigate the unsteady internal flow condition in detail, the numerical analysis using low viscous fluid was conducted. In this paper, the unsteady internal flow conditions of centrifugal pump using low viscous fluid were clarified by experimental and unsteady numerical analysis results. In addition to that, the design method based on the internal flow was considered.


Performance Analysis of Mini Centrifugal Pump with Splitter Blades


Study of Emulsification Mechanism in a Pressure Type Homogenizer

圧力式ホモジナイザーの乳化メカニズムに関する研究

Emulsification technique is used in broad fields, such as food, chemistry, and medical treatment, and the range of use has been spreading still more. A pressure type homogenizer consists of a plunger pump and a valve part with a narrow channel. It generates the effects of shear, a turbulent flow and cavitation at very short time, and then makes a homogeneous emulsification state. If the flow pattern in the valve can be solved in more detail, the more effective and stabilized emulsification will be attained. However, since the measurement of the size, the pressure and the flow velocity in a narrow gap space by experiments is difficult, the details of the mechanism of emulsification by the shear, the turbulent flow, the cavitation and a collision have not been clarified enough. In this research, the size of gap is first calculated from the theoretical equation assumed to be laminar flow, based on the Reynolds number of the gap flow. Next, the pressure, the flow velocity, shearing stress, etc. are calculated. Then, the emulsification mechanism of each part of the valve is clarified by expressing the droplet size as a function of the gap size, the shearing stress and the exit velocity.

Transactions of The Japan Society of Mechanical Engineers, Series B

日本機械学会論文集(B編)


Performance Characteristics of Small-Sized Cooling Fan with High Pressure and High Flow Rate

高圧・高風量な小型冷却ファンの性能特性について

Data center has been built with spread of cloud computing. Further, electric power consumption of it is growing rapidly. High power cooling fans are used for servers in the data center and there is a strong demand to increase power of it because of increase of quantity of heat from the servers. Contra-rotating rotors have been adopted for some of the high power cooling fans. It is important to clarify complicated internal flow condition and influence of a geometric shape of the cooling fans on performance and internal flow condition to achieve the high performance cooling fans. The performance characteristics of the front and rear rotor of high power contra-rotating small-sized cooling fan is clarified by numerical analysis and design guideline to improve the performance is discussed.


Internal Flow Condition of High Power Contra-Rotating Small-Sized Axial Fan

International Journal of Fluid Machinery and Systems


Unsteady Internal Flow of High Pressure and Large Flow Rate Small-Sized Cooling Fan

高圧・高風量な小型冷却ファンの非定常内部流れについて

Data center has been built with spread of cloud computing. Further, electric power consumption of it is growing rapidly. High pressure and large flow rate cooling fans are used for servers in the data center and there is a strong demand to increase pressure and flow rate of it because of increase of quantity of heat from the servers. Contra-rotating rotors have been adopted for some of high pressure and large flow rate cooling fans. It is important to clarify unsteady internal flow condition of it for high performance and stable operation. Numerical analysis of high pressure and large flow rate cooling fan with 40 mm square was conducted and unsteady internal flow conditions were discussed in this research.


Unsteady Internal Flow Conditions of Mini Centrifugal Pump with Splitter Blades


Study on a Contra-Rotating Small Hydro Turbine

二重反転形小型ハイドロタービンに関する研究


Performance and Internal Flow Condition of Mini Centrifugal Pump with Splitter Blades


Study on Contra-Rotating Small-Sized Axial Flow Hydro Turbine


クロスフローファンの入口予旋回流れとその制御

クロスフローファンの入口予旋回流れとその制御

日本機械学会論文集(B編)


Influence of Blade Row Distance on Performance and Flow Condition of Contra-Rotating Small-Sized Axial Fan

International Journal of Fluid Machinery and Systems


低粘度流体食品用遠心ポンプのチップクリアランスが性能と内部流れに及ぼす影響

低粘度流体食品用遠心ポンプのチップクリアランスが性能と内部流れに及ぼす影響


Effects of Rotational Speed Control on Internal Flow of Contra-Rotating Small-Sized Axial Fan

二重反転形小型軸流ファンの回転速度制御が内部流れに及ぼす影響

Small-sized axial fans are used as air cooler for electric equipments. But there is a strong demand for higher power of fans according to the increase of quantity of heat from electric devices. Contra-rotating rotors were proposed for the improvement of the performance of small-sized axial fans and the advantages of it on the point of view of the performance were confirmed. On the other hand, the contra-rotating small-sized axial fan is operated at off design flow rates and the performance deteriorates at off design flow rates. Therefore, rotational speed control of each front and rear rotor is proposed for the improvement of the performance at off design flow rates in this research. In the present paper, the performance of the contra-rotating small-sized axial fan under the rotational speed control is shown and the internal flow conditions of each rotational speed control method are clarified by the numerical analysis results.


Unsteady flow condition of contra-rotating small-sized axial fan


Performance and Internal Flow of High Power Cooling Fan

高出力空冷ファンの性能と内部流れについて

Data center has been built with spread of cloud computing. Further, electric power consumption of it is growing rapidly. High power cooling fans are used for servers in the data center and there is a strong demand to increase power of it because of increase of quantity of heat from the servers. Contra-rotating rotors have been adopted for some of the high power cooling fans. It is important to clarify complicated internal flow condition and influence of a geometric shape of the cooling fans on performance and internal flow condition to achieve the high performance cooling fans. Numerical analysis of a cooling fan with 40 mm square was conducted and influence of tip clearance on performance was investigated experimentally in this research.


Influence of Blade Outlet Angle and Blade Thickness on Performance and Internal Flow Conditions of Mini Centrifugal Pump


翼先端流れに着目した斜流ポンプの不安定特性改善に関する研究

翼先端流れに着目した斜流ポンプの不安定特性改善に関する研究

Instability characteristics generated with partial flow rate in a mixed-flow pump have bad influence during the pump operation. This paper is described on the improvement of instability characteristics in a mixed-flow pump based on flow near blade tip. At first it was examined about the influence of the suction flow channel diameter which gave to performance and internal flow of mixed-flow pumps experimentally. Furthermore, it was examined about influence when it combined control of blade loading distributions near blade tip. As a result, pump efficiency fell at flow rate of the best efficiency a little when we reduced suction flow channel diameter. However, instability characteristics were improved so that a reverse flow developed at the impeller inlet tip side with the decrease of the flow rate slowly. In addition, about 82% head falls of instability characteristics were improved when we combined reduction of suction diameter and the impeller of aft-loading.

Transactions of The Japan Society of Mechanical Engineers, Series B

日本機械学会論文集(B編)


Study on Performance and Internal Flow of Fluid Food Pump

流体食品ポンプの性能と内部流れに関する研究

Fluid machineries for fluid food have been used in wide variety of field i.e. transportation, filling and improvement of thequality of fluid food. Although, flow conditions of it are quite complicated because fluid food is different from water.Therefore, the design method based on the internal flow conditions is not conducted. In this research, turbo-pump havingsmall number of blade number was used to decrease shear loss and keep wide flow passage. In this paper, performance andinternal flow conditions of turbo-pump using low viscous fluid were clarified by experimental and numerical analysisresults.


Study on Performance and Flow Condition of Cross-flow Wind Turbine with a Symmetrical Casing

Journal of Fluids Engineering - Transactions of the ASME


Study on Performance and Internal Flow Condition of Mini Turbopump

小型ターボポンプの性能特性と内部流れに関する研究

Mini turbo-pumps which have a diameter smaller than 100 mm are utilized in many fields. It is desirable that the miniturbo-pump design is as simple as possible due to the limitation of the precision for manufacture. But the design method forthe mini turbo-pump is not established. Therefore, we started the research of the mini turbo-pump for the purpose of developmentof high performance mini turbo-pump with simple structure. It is clarified from the numerical results that head andefficiency decrease drastically with the increase of the tip clearance and the flow condition near the tip region is influencedby the leakage flow from the blade tip. In the present paper, the performance of the mini turbo-pump is shown and the internalflow condition is clarified with the results of the numerical flow analysis. Furthermore, the effects of the tip clearance onthe performance are investigated and high performance rotor design for mini turbo-pump would be considered.


斜流ポンプの内部流れと不安定特性に及ぼす翼端羽根負荷分布の影響

斜流ポンプの内部流れと不安定特性に及ぼす翼端羽根負荷分布の影響

Instability characteristics generated with partial flow rate in a mixed-flow pump have bad influence during the pump operation. In this paper, a method to control blade loading distributions of the mixed-flow pump by a simple and easy method is shown. This method was applied to control of the blade loading distribution of the blade tip in mixed-flow pumps. Furthermore, performance and the internal flow of these pumps were examined experimentally. As a result, head and pump efficiency fell at flow rate of the best efficiency in the impeller of aft-loading, but the instability characteristics were largely improved. In addition, a reverse flow suddenly developed at the impeller inlet tip side with the decrease of the flow rate in the impeller of fore-loading, but it was shown clearly that the reverse flow did not suddenly develop in the impeller of aft-loading.

日本機械学会論文集(B編)


小型ターボポンプの羽根出口角が羽根車性能に及ぼす影響

小型ターボポンプの羽根出口角が羽根車性能に及ぼす影響


The Effect of Blade Outlet Angle on Performance and Internal Flow Condition of Mini Turbo-Pump


二重反転形小型軸流ファンの性能特性と内部流れに関する研究

二重反転形小型軸流ファンの性能特性と内部流れに関する研究

Small-sized axial fans are used as air cooler for electric equipments. But there is a strong demand for higher power of fans according to the increase of quantity of heat from electric devices. Therefore, higher rotational speed design is conducted although, it causes the deterioration of efficiency and the increase of noise. Then the adoption of contra-rotating rotors for the small-sized axial fan is proposed for the improvement of performance. In the present paper, the performance curves of the contra-rotating small-sized axial fan with 100mm diameter are shown and the velocity distributions with the designed flow rate at the inlet and the outlet of each front and rear rotors are clarified with experimental results. Furthermore, the flow conditions between front and rear rotors of the contra-rotating small-sized axial fan are investigated by numerical analysis results and higher performance design of the contra-rotating small-sized axial fan are discussed.

日本機械学会論文集(B編)


Performance and Flow Condition of Contra-rotating Small-sized Axial Fan at Partial Flow Rate

International Journal of Fluid Machinery and Systems


未加硫ゴムの充填過程における流れの現象と不均一な充填

未加硫ゴムの充填過程における流れの現象と不均一な充填

Rubber products like oil seal are produced by vulcanization molding and the vulcanization molding of rubber product is performed by past experience, trial and error. It is important issues to decrease the product cost, reduce defective products and solve the environmental problems by saving natural resources. If the vulcanization moldings of rubber products are reappeared by computer simulation, it is very useful and it could contribute to solve the above problems. In order to reduce surplus rubber and defective product, numerical analysis of flow phenomena of unvulcanized rubber was performed using commercial software FIDAP. In several types of rubber product models, the analysis was conducted taken the characteristic of visco-elasticity fluid obtained by experiment, without considering the effect of the heat. And experiments were conducted for the comparison of numerical results and actual phenomena. In the experiment, vulcanization process was stopped by arbitrary interval. Then the filling state and the shape of the rubber at each interval are observed in numerical and experiment results. The results showed that the filling state of numerical results represented good agreement with the experimental results. And it was clarified from the numerical analysis that shear stress acted when the unvulcanized rubber flowed in narrow channel and there was the relation between pressure and velocity. In the present paper, the flow phenomena under the condition of the compression molding are shown and the optimum flow conditions are discussed from the numerical results. Furthermore mechanism of occurrence of defective products is considered with the experimental and the numerical results.

日本機械学会論文集(B編)


小型軸流ファンへの二重反転形羽根車の採用について

小型軸流ファンへの二重反転形羽根車の採用について

Small-sized axial fans are used as air cooler for electric equipments. But there is a strong demand for higher power of fan according to the increase of quantity of heat from electric devices. Therefore, higher rotational speed design is conducted although, it causes the deterioration of the efficiency and the increase of noise. Then, the adoption of contra-rotating rotors for the small-sized axial fan is proposed for the improvement of performance. In the present paper, the experimental results of a conventional small-sized axial fan with 100 mm diameter are shown and the important points to adopt the contra-rotating rotors are considered with these results. Furthermore, the performance and the flow field of the contra-rotating smallsized axial fan are clarified by the numerical analysis results and the advantages of the adoption of the contra-rotating rotors for the small-sized axial fan are discussed.


Performance and Flow Condition of Small-Sized Axial Fan and Adoption of Contra-Rotating Rotors


ケーシング幅が二重反転多翼ファンの性能に及ぼす影響

ケーシング幅が二重反転多翼ファンの性能に及ぼす影響

A sirocco fan using contra-rotating rotors in which an inner rotor was settled inside the sirocco fan rotor and each rotor rotated in an opposite direction was proposed for the purpose of getting the higher pressure and making the structure of a sirocco fan compact more. If the high discharge pressure is obtained with the adoption of the contra-rotating rotors, it could be used for various purposes. Pressure coefficient of the sirocco fan with contra-rotating rotors was 2.4 times as high as the conventional sirocco fan and the maximum efficiency point of contra-rotating rotors shifted larger flow rate than the conventional sirocco fan. On the other hand, it was clarified from the flow measurement results that the larger back flow region than conventional one occurred at the shroud of the casing in the case of contra-rotating type and this would induce decrease of the efficiecy. In the present paper, the performance of the conventional sirocco fan and the sirocco fan with contra-rotating rotors are shown and the internal flow field at the outlet of the outer rotor of both cases is clarified Then, the effect of casing width on the performance and the internal flow field is investigated and the casing width which would be suitable for the contra-rotating type would be discussed.

日本機械学会論文集(B編)


The shapes of valves and emulsification action in a homogenizer

ホモジナイザーのバルブ形状と乳化効果

The homogenizer basically consists of a high-pressure plunger pump usually with triple plungers to minimize pressure fluctuations and a homogenizing valve with a narrow gap. However, the flow within the homogenizing valve is not clarified theoretically. In this paper, the influence of shape modification of the homogenizing valve was investigated in the emulsification action. The experiments using a small homogenizer are conducted. We studied the influence of the flow pattern (pressure distributions, shear stress) on the droplet size distribution obtained in the experiment, and investigated the relation between the shear flow and the emulsification action in the homogenizing valve. In this experiment, two valve types (sharp type and flat type) were applied. The pressure drop in the valve and the parallel gap part length were changed. The droplet size distribution results obtained in the emulsification tests could be analyzed based on the average value of the wall shear stress in the parallel gap part through the above experiments and calculation results.

圧力式乳化機は，安定した乳化が得られるため幅広い分野で利用されている．しかし，圧力式乳化機では，せん断・乱流・キャビテーションが同時に引き起こされ，乳化作用に対し重要度が高いものから，せん断・乱流・キャビテーションをランク付けすることは非常に難しい．圧力式乳化機の均質バルブ内の流れについて研究されているが，おもに圧力の違いで検討されており，依然として明らかにされていない部分がある．そこで，本研究では，小型の圧力式ホモジナイザーの均質バルブ形状を変更し，形状の違いによる影響について調査した．また，バルブ隙間の流れが放射状の層流であるとした計算式からバルブ隙間を算出し，均質バルブ内の圧力・せん断応力の代表値を導いた．さらにせん断応力の代表値による計算結果と実験による乳化後の粒子径を比較し，その代表値による乳化作用の整理式を提案できた．


Study on Performance Improvement of Cross-Flow Wind Turbine with Symmetrical Casing

A cross-flow wind turbine has a high torque coefficient at a low tip speed ratio. Therefore, it is a good candidate for use as a self-starting turbine. Furthermore, it has low noise and excellent stability; therefore, it has attracted attention from the viewpoint of applications as a small wind turbine for an urban district. However, its maximum power coefficient is extremely low (10 %) as compared to that of other small wind turbines. In order to improve the performance and the flow condition of the cross-flow rotor, symmetrical casings with a nozzle and a diffuser are proposed and experimental research with two types of symmetrical casings is conducted. The maximum power coefficient is obtained as Cpmax = 0.17 for casing 2 and Cpmax=0.098 for casing 1. In the present study, power characteristics of the cross-flow rotor and those of the symmetrical casings with the nozzle and the diffuser are investigated. Then, the performance and internal flow patterns of the cross-flow wind turbine with the symmetrical casings are clarified. After that, the effect of the symmetrical casings on the performance of the turbine is discussed on the basis of the analysis results.


圧力式ホモジナイザーにおける内部流れと乳化効果の研究

圧力式ホモジナイザーにおける内部流れと乳化効果の研究

The homogenizer is extensively used to emulsify, disperse the products in various industrial fields including: food, chemical, pharmaceutical and biotechnology. The homogenizer basically consists of a high-pressure plunger pump usually with triple plungers to minimize pressure fluctuations and a homogenizing valve with a narrow gap. However, the flow within the homogenizing valve is not clarified theoretically. If the flow pattern within the homogenizing valve could be solved, a more efficient and stabilized emulsification could be carried out. In this paper, the influence of shape modification of the homogenizing valve was investigated in the emulsification effect. The experiments using a small homogenizer are conducted. We studied the influence of the flow pattern (velocity distributions, pressure distributions, shear stress) on the drop size distribution obtained in the experiment, and investigated the relation between the average value of wall shear stress and the emulsification effect in the homogenizing valve. The flow patterns were investigated using a Computational Fluid Dynamic model of the flow in the homogenizing valve. The purpose of this paper is to clarify the effects of differences in the shapes of valves on the results of emulsification.

Transactions of The Japan Society of Mechanical Engineers, Series B

日本機械学会論文集(B編)


Internal Flow Measurement with LDV at Design Point of Contra-Rotating Axial Flow Pump

The adoption of the contra-rotating rotor has been proposed in response to a demand for the axial flow pump with higher specific speed. The internal flow field and blade rows interactions between front and rear rotors should be considered in the design for higher performance and more stable operation, but has not been clarified yet. The flow field in contra-rotating axial flow pump was measured at various flow rates with the LDV and wall pressure measurements. In the present paper, the experimental and numerical results in the flow field between front and rear rotors are shown at the design flow rate and the flow behaviors are discussed, related on blade loading, blade tip leakage flow, wake and blade rows interaction.


The Study on The Flow Phenomena of Unvulcanized Rubber in Process of Filling

未加硫ゴムの圧縮成形時における流動現象に関する研究

Rubber products, e.g. oil seal, are produced by vulcanization molding and the vulcanization molding of rubber product is performed by past experience, trial and error. In order to reduce surplus rubber and defective product, numerical analysis of flow phenomena of unvulcanized rubber was performed using FIDAP. The analysis was conducted taken the characteristic of unvulcanized rubber obtained by experiment, without considering the effect of the heat. The results showed that the filling state of numerical results represented good agreement with the experimental results. And it was clarified from the numerical results that high shear stress acted during unvulcanized rubber fill up to a narrow channel such as side surface of metal insert. In this paper, the flow phenomena under the condition of vulcanization molding are shown and the optimum flow condition would be discussed with experimental and numerical results.

日本機械学会論文集(B編)


対称形ケーシングによるクロスフロー風車の高性能化に関する研究

Cross-flow wind turbine has a characteristic of high torque coefficient at low tip speed ratio. Therefore, it is good for the self-starting. Furthermore, it is low noise and superior to stability so that it attracts attentions as the city type small-sized wind turbine for urban district. But the maximum power coefficient is extremely low as 10% compared with other small-sized wind turbines. In order to improve the performance and the flow condition of cross-flow rotor, a symmetrical casing with a nozzle and a diffuser was proposed and experimental research with two kinds of symmetrical casings was conducted. The maximum power coefficient was obtained as C_<pmax>=0.17 for the casing 2, however as C_<pmax>=0.098 for the casing 1. In the present paper, power characteristics of cross-flow rotor and one of a symmetrical casing with a nozzle and a diffuser were investigated. Then the performance and internal flow field of a cross flow wind turbine with the symmetrical casing were clarified. After that, the effect of the symmetrical casing on performance would be discussed with these results.

日本機械学会論文集(B編)


二重反転形軸流ポンプにおける設計流量点流れのLDV計測

The adoption of the contra-rotating rotor has been proposed in response to a demand for the axial flow pump with higher specific speed. The internal flow field and blade rows interactions between the front and rear rotors should be considered in the design for higher performance and more stable operation, but has not been clarified yet. The flow field in contra-rotating axial flow pump was measured at various flow rates with the LDV and wall pressure measurements. In the present paper, the experimental and numerical results in the flow field between front and rear rotors are shown at the design flow rate and the flow behaviors are discussed, related on blade loading, blade tip leakage flow, wake and blade rows interaction.

日本機械学会論文集(B編)


Performance and Internal Flow of Sirocco Fan Using Contra-Rotating Rotors


Performance Test and Flow Measurement of Contra-Rotating Axial Flow Pump


Blade Rows Interaction of Contra-Rotating Axial Flow Pump in Pressure Field on Casing Wall

An application of contra-rotating rotors has been proposed against a demand for developing higher specific speed axial flow pump with more compact structure, higher efficiency and higher cavitation performance. The blade rows interaction between front and rear rotors should be taken into account in pump design for stable operation and reduction of unsteady losses. The measurements of static pressure distributions on casing wall with the phase locked sampling method are carried out for two types of the rear rotors. In the present paper the difference of the rear blade interaction and the unsteady pressure fluctuation are clarified. The pressure fluctuations are more remarkable in the front rotor than in the rear rotor and they are caused by rear rotor pressure field. The effects of pressure fluctuations will be discussed in more details toward understanding the blade rows interaction in the contra-rotating axial flow pump.

JSME International Journal, Series B: Fluids and Thermal Engineering


二重反転形軸流ポンプのケーシング壁面静圧計測と翼列間干渉

二重反転形軸流ポンプのケーシング壁面静圧計測と翼列間干渉

An application of contra-rotating rotors, consisting of front and rear rotors rotating in the opposite direction each other, has been proposed against a demand for developing higher specific speed axial flow pump with more compact structure, higher efficiency and higher cavitation performance. The blade rows interaction between front and rear rotors should be clarified for stable operation and reduction of unsteady losses. In the present paper, static pressure distributions on casing wall are shown at two flow rates by measuring with phase locked sampling method, where double trigger signals from rotation pick-ups equipped on both front and rear rotor shafts are used. From the comparison between experimental results of two types of the rear rotors, one of which has three blades with long chord length and the other has five blades with short length, the difference of the rear blade interaction and the unsteady pressure fluctuation are identified. The pressure fluctuations by rear rotor were observed even upstream of the front rotor and upstream flow field changed due to the pressure fluctuation in the former case. The effect of pressure fluctuation to the flow field will be discussed in more details and the guideline of rear rotor design will be considered.

日本機械学会論文集(B編)


二重反転形軸流ポンプの気液二相流性能と後段翼車の回転数制御

二重反転形軸流ポンプの気液二相流性能と後段翼車の回転数制御

An application of contra-rotating rotors, consisting of front and rear rotors rotating in the opposite direction each other, has been proposed against a demand for developing higher specific speed axial flow pump with more compact structure, higher efficiency and better cavitation performance. Air/water two-phase flow performance of contra-rotating pump has to be, also, investigated as axial flow pumps are used for standby operations of air-lock and air/water mixing discharge to prevent floods. In the present paper, experimental results on air/water two-phase flow performance of test pump of contra-rotating rotors (RR1 Type) are shown and compared with those of conventional axial flow pump, consisting of a front rotor and a rear stator. Effects of changes of rear rotor rotational speed, which is an advantage of contra-rotating axial flow pump, on two-phase flow performance of RR1 type are discussed. It is shown that air/water two-phase flow performance of contra-rotating axial flow pump is capable to be improved by this control procedure for rear rotor rotational speed.

日本機械学会論文集(B編)


Pressure Measurement on Casing Wall and Blade Rows Interaction of Contra-Rotating Axial Flow Pump


二重反転形軸流ポンプの後段翼車設計に関する実験的考察

二重反転形軸流ポンプの後段翼車設計に関する実験的考察