Fluid machineries for fluid food have been used in wide variety of field i.e. transportation, the filling, and improvement of the quality 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 having small number of blade number was used to decrease shear loss and keep wide flow passage. The influence of the tip clearance was investigated by the numerical analysis using the model with and without the tip clearance. In this paper, the influence of the tip clearance on performances and internal flow conditions of turbo-pump using low viscous fluid were clarified by experimental and numerical analysis results. In addition, the design method based on the internal flow was considered. Further, the influences of viscosity on the performance characteristic and internal flow were investigated.

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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.

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The effect of nozzle-bucket axial gap length on the unsteady force for buckets was studied by using new method to predict the unsteady force which is induced by potential field and wake interactions between nozzles and buckets of steam turbines. The new method can separate the unsteady force into two components due to potential field and wake interactions, and the effect of nozzle-bucket axial gap length is obtained. A simple relationship between the nozzle-bucket axial gap length and the unsteady force was found to give easy and reliable prediction of the unsteady force.

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Variable Geometry System(VGS)is widely applied to the nozzle vane for the radial inflow turbine of automotive turbochargers to optimize the power output at each operating condition. The setting angle of nozzle vane influences the secondary flow structure in the turbine impeller. Moreover, a scallop is usually present at the back-face of the impeller to minimize the inertia. However it may reduce the aerodynamic performance of turbine impeller due to the appearance of the hubside leakage flow. Therefore, it is very important to clarify the influence of the scallop configuration on the aerodynamic loss generation in the impeller channel at wide range of operating condition. In this study, the numerical calculations were carried out for the flow in radial turbine with the parameters of the inlet flow angle at nozzle and the scallop radius ratio of turbine impeller. The computed results revealed that the hub-side leakage flow was strongly affected by the inlet flow angle and the scallop radial ratio.

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In a radial-inflow turbine of the automotive turbocharger, the variable nozzle guide vane is an indispensable component to achieve the high aerodynamic performance over the wide operating range. By changing the nozzle throat area, it is enabled to optimize the impeller inlet flow velocity for several engine speeds from the idle to the rated power condition. However, the aerodynamic excitation force caused by the rotor-stator interaction between the nozzle vanes and the impeller has become a large issue for the variable nozzle turbine. In this paper, three-dimensional numerical simulations were conductedto investigate the unsteady stage interaction. Two parameters are mainly focused, which are the nozzle vane angle and the stage expansion ratio. When the nozzle is fixed at the open condition, the excitation force is proportional to the turbine inlet pressure. On the other hand, when the nozzle is at the closed or medium opened condition, the shock wave is generated near the nozzle outlet by the rapid flow acceleration within the nozzle passage and the interaction between the nozzle potential flow field and the impeller blades causes the large excitation force on the impeller blade surface.

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In this study, to clarify the specific mechanism of noise and vibration on a propeller fan mounted in the rectangular duct is aimed. Since the channel in the rectangular duct is expanded partially on the diagonal line of the duct, the velocity of the main flow domain in the wake decreased at the diagonal position. The pseudo four vanes were made by the pressure distribution on the impeller surface due to the velocity distribution. When the four vanes interfere with the fourteen rotors, the discrete frequency noise of the second harmonics in the axial direction of the duct was hard to decrease on the condition of this experiment. The ring-shaped shroud attached to the propeller removed the influence of the noise and vibration in the rectangular duct.

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In experiments of water hammer phenomenon including column separation, pressure spike that is much bigger than the supposed water hammer pressure is often observed. That pressure arises not only in the experimental model but also in full scale system. This paper describes the mechanism of such pressure spike and the effect of valve closure time on water hammer with column separation. Computational model based on the Discrete Free Gas Model with 3-element Voigt model is used in this study. From the comparison of the numerical solution with experimental results, it is shown that the pressure spike occurs because of the difference of acoustic impedance of two connected pipes. Observed length of vapor slug at upstream end are slightly longer than that of numerical solution. The volume of free gas in the computational model has different meanings for various states of unsteady cavity flows.

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The aim of this investigation was to clarify the mechanism of improving power performance of Savonius type hydraulic turbine with a flat shield plate. A model of a Savonius type hydraulic turbine was constructed and, a relation between a runner and the flat shield plate was investigated to arrive at an optimum installation condition. Effects of installation parameters, namely angles of setting and tilting the flat shield plate, and a distance between the runner and the flat shield plate were examined. Then the flow field around the runner was studied visually to clear influence of the flat shield plate setting conditions. This study found the effects of a vortex from top edge of the shield plate that prompt impinging flow towards convex side of the returning blade. Finally it was clarified the favorable flat shield plate installation condition. Then the CPmax was obtained 49%.

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