[en] An analysis on the adhesive wear of heat exchangers tubes of PWR electric power plants is presented. The obtained results show that the proposed model is adequate, since the predicted tube wear life reasonably matches the recorded tube failure life. Some comments about the phenomenon are presented, in special their non linear characteristics and the uncertainty on the appropriate values of relevant design parameters. (Author)

[en] A PWR Emergency Core Cooling Simulator Loop for investigations of the phenomena involved, in a postulated Loss-of-Coolant Accident, during the Reflooding Phase, was designed. The functions of each component of the loop and the system operation sequence are presented. (Author)

[en] Considering a turbulent flow in a wire wrapped rod bundle geometry with triangular array, typical of a LMFBR fuel element, the wall shear stress distributions were measured by using Preston tubes, for Reynolds numbers equal to 33000 and 77000. Nondimensionalized by its average value, the wall shear stress distribution presents abrupt variations in its behavior and is not a function of the Reynolds number. (Author)

[en] An experimental study was developed for a vertical gas solid two phase flow with heat transfer by analysing the gradient of both static pressure and temperature alongside the system. The measurements were used to produce the isothermal hydrodynamic entry lenght and the gas-solid heat transfer coefficient as well as the influence of the solid particle. (Author)

[en] Some papers on fluid flow and heat transfer for elements of nuclear power plants are presented. (E.G.)

[en] Equations for calculating the loss coefficient in combining flows in tee functions are obtained by an integral linear momentum balance. It is a practice, when solving this type of problem, to neglect the pressure difference in the upstream location as well as the wall-fluid interaction in the lateral branch of the junction. In this work it is demonstrated the influence of the above parameters on the loss coefficient based on experimental values and by apropriate algebraic manipulation of the loss coefficient values published by previous investigators. (Author)

[en] An experimental system was developed in order to get data on the dynamics of a gas-solids flow in a fast fluidized bed. Measuring the mass flow rate of gas and solids and static pressure alongside the bed it was possible to calculate the longitudinal porosity profile of the system. (Author)

[en] The results of an experimental investigation in divided-flow fittings head loss are presented. The main purposes are to verify the minimum value of the coefficient and to see it as a Carnot-Borda head-loss. The Reynolds number influence on head loss coefficients were qualitatively identified. The 90 degrees cross section fittings used in this experiment had a unitary area ratio. (Author)

[en] The flow around two closely-spaced cylinders, moving harmonically in aninfinite fluid region is analysed. The amplitude motion is assumed to be small and the viscosity is neglected. Under such assumptions the complex velocity potential can be written as a series; each term of such a series represents a dipole inside one of the cylinders. As the number of the term increases the respective dipole is located nearer the boundary. A generalized from for the Blasius relations, which is applied to non steady state flows, is used to obtain the hydrodynamic loads. (Author)

[en] A general theory for the dynamic analysis of anisotropic thin cylindrical shells containing flowing fluid is presented. The shell may be uniform or non-uniform, provided it is geometrically axially symmetric. This is a finite- element theory, using cylindrical finite elements, but the displacement functions are determined by using classical shell theory. A new solution of the wave equation of the liquid finite element leads to an expression of the fluid pressure, p, as a function of the nodal displacements of the element and three operative forces (inertia, centrifugal and Coriolis) of the moving fluid. (Author)