We analyze the laminar motion of incompressible fluids in self-acting thrust bearings with spiral grooves with inner or external pumping. The purpose of the study is to find some mathematical relations useful to approach the theoretical functionality of these bearings having magnetic controllable fluids as incompressible fluids, in the presence of a controllable magnetic field. This theoretical study approaches the permanent motion regime. To validate the theoretical results, we compare them to some experimental results presented in previous papers. The laminar motion of incompressible fluids in bearings is described by the fundamental equations of fluid dynamics. We developed and particularized these equations by taking into consideration the geometrical and functional characteristics of these hydrodynamic bearings. Through the integration of the differential equation, we determined the pressure and speed distributions in bearings with length in the “pumping” direction. These pressure and speed distributions offer important information, both quantitative (concerning the bearing performances) and qualitative (evidence of the viscous-inertial effects, the fluid compressibility, etc.), for the laminar and permanent motion regime.

This paper presents the results of a study of a magnetorheological fluid (MRF) damper. The principle could be used for such applications as seismic protectors for civil structure (where the dimensions are chosen to handle the greatest forces) or shock absorbers for the automotive industry (where the dimensions are chosen to accommodate heating effects). We describe the preparation method and some characteristics of the MRF, the experimental method (we used a hydraulic linear motor and pressure measurements), and the main experimental results. The external force required to move the damper increases several times when the magnetic field is applied.

Heavy automotive vehicles and automobiles are, almost exclusively, equipped with automatic hydrodynamic transmissions. This article is devoted to one of the possibilities to control the operation of hydrodynamic transmissions through partially filling the torque converter with liquid. The investigation was centred on torque converters with two-phase flows, namely oil-air. There are proposed theoretical, numerical models and an experimental facility, testing rig, was erected.The obtained results are in the hydrodynamic field (velocities and pressures) in the torus and the characteristic curves of the two-phase flow hydrodynamic transmission.

We analyze the motion of viscous and incompressible liquids in the annular space of controllable hydraulic resistances with a cylindrical linear slide-valve. This theoretical study focuses on the turbulent and steady-state motion regimes. The hydraulic resistances mentioned above are the most frequent type of hydraulic resistances used in hydraulic actuators and automation systems. To study the liquids' motion in the controllable hydraulic resistances with a linear cylindrical slide-valve, the report proposes an original analytic method. This study can similarly be applied to any other type of hydraulic resistance. Another purpose of this study is to determine certain mathematical relationships useful to approach the theoretical functionality of hydraulic resistances with magnetic controllable fluids as incompressible fluids in the presence of a controllable magnetic field. In this report, we established general analytic equations to calculate (i) velocity and pressure distributions, (ii) average velocity, (iii) volume flow rate of the liquid, (iv) pressures difference, and (v) radial clearance.