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This paper reports about experimental investigations of rotordynamic fluid force moments on an open type centrifugal impeller in precessing motion. The results show, at design flow rate, that the fluid force moment becomes destabilizing in the region of negative precession frequency ratio: -0.3

This paper presents the experimental results of rotordynamic forces on an open-type centrifugal impeller in whirling motion. For the whirling open-type impeller, the variation of the tip clearance produces the rotordynamic force. It was found that, [1] destabilizing force occures at small whirling/rotation ratio throughout all of the flow range, and [2] At smaller flow rate the magnitude of the force changes dramatically at a whirling/rotation ratio. The forces estimated from unsteady pressure distribution on the casing and that estimated from the pressure difference across the blades are compared with the measured rotordynamic forces.

The history of mechanical engineering education at the University of Tokyo is surveyed and the trend of evolution in the curricula and their requirement conditions is studied. The survey covers the past 106 years between 1886 and 1991, and ten representative curricula are selected from that period. Courses of each curriculum are classified into seven categories and listed for comparison. The history of curricula indicates that the traditional mechanical engineering curriculum, which features heavy concentration in applied mechanics education, took its present form half a century ago and continued until the mid 1980s. The shift from power-driven machines to information-driven ones required qualitative change in mechanical engineering education, and a new generation of curriculum with the combination of natural and artificial sciences appeared in recent years.

Thin-film formation on a rotating disk during the spin-coating process is analyzed. In the experiments for a solution of PMMA (polymethyl methacrylate) solute and chlorobenzene solvent, the final film thickness of dry film formed on silicon wafers for integrated circuits is measured with an ellipse thickness meter. Also, the transient film thickness during the entire film formation process on a rotating optical glass is measured using a laser displacement meter. A numerical calculation considering heat and mass transfer such as solvent evaporation is performed using a one-dimensional complete model proposed by the authors for each phase of liquid film and adjacent gas phase. Satisfactory agreement is obtained between these numerical and experimental results and the effect of various process parameters, e.g., spinning speed and initial film thickness, is clarified by this study.

An air-water two phase flow recirculating water test tunnel was constructed. This tunnel was designed and constructed to measure the performance of either an isolated hydrofoil or a cascade of hydrofoils under variable two phase condition. Void fraction measuring system using Point Electric Resistivity Probe was also developed. In this paper, the specification and the basic characteristics of the tunnel, such as the distribution of velocity, void fraction and bubble radius at the test section, are reported. As an example of test results, the distribution of void fraction behind an airfoil is shown.

Flow pattern in the rotor of turbomachines changes discontinuously when flow rate decreases beyond a critical limit. Typical examples are seen in reverse flow at the suction flow at the suction of axial and centrifugal impellers, in the reversal of discharge direction of centripetal impellers, etc. The purpose of this study is to find a clue to the criteria which initiate the transition from one pattern to the other. Non-staggered rotor was installed in an annulus between two stators with plane-symmetric configurations, so that the flow condition became perfectly symmetric. The flow pattern took either discharge or recirculation mode according to the geometry of rotor and stator. Transition criteria were discussed based on the measured driving torque and discharge flow.