This paper describes a pressure measurement method of the transonic flow through the turbine cascade by means of the suction-type shock tunnel. The present method which uses silicon oil containing tubes is characterized by an improvement in the response of the pressure-time. It is shown that the values of the static pressures on the blade surfaces measured by the present method almost agree with those by the optical method. The experimental results using a Pitot tube are also shown as an example of this method in order to obtain the total pressures downstream of the cascade.
An ion engine is one of the most advantageous thrusters for orbit transfer of space vehicles or station keeping of large and long life satellite because of its high specific impulse. The ion engine system includes the ion engine, power supply unit and command interface unit, then the compatibility and interaction between them are important problems. A simulation system is necessary for a design tool at its development phase and for prediction means at the space operation. The ion engine is a nonlinear and multivariable system which is controlled by 10 power supplies. Its operation characteristics are dependent on the thermal condition of several components, propellant particle density and power supply characteristics. Thermal model which is the dominant factor of the dynamics is derived. Most plasma models are described generally by rational polynomials and their unknown parameters are identified by the steepst descent method. Each model is identified individually and is integrated. Param-eters of the integrated models are adjusted from the view of the total system response. The computer aided parameter tuning method is employed and it takes effect to increase accuracy of the simulation. This simulation system is applied and compared with the real system. The improvement procedures of the ion engine system are presented for the application example of the simulation system.
A wrinkling analysis is presented for cylindrical sandwich shells subjected to torsion. The core of sandwich shells is assumed to be homogeneous and anti-plane orthotropic material, while the two facings are of equal thickness and have own bending stiffnesses. As the whole bending stiffness of sandwich shells is taken in the analysis, so buckling of the analysis unifies the wrinkling and the over-all buckling. A length of cylindrical shells is so long that the boundary conditions do not affect to the wrinkling loads. If a helical buckling deformation is assumed, then stresses in the core can be expressed in a matrix form in terms of facing displacements. Finally a DONNEL's type of equilibrium of the facings is reduced to algebraic eigenvalue equations. The numerical results obtained by this method were compared with the solutions of over-all buckling analysis by MARCH and KUENZI, and the fact, that the wrinkling stresses are lower than the over-all buckling stresses for cylindrical sandwich shells subjected to torsion when the core is relatively thick, is revealed.