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The aim of this work was to investigate the rate of heat transfer from a moving radial plate clutch surface. The paper presents experimental results over a range of angular speeds (Q) and fluid gap widths (h), which are then favorably compared to analytical and Computational Fluid Dynamics (CFD) solutions for the same geometry and operating conditions. Verifying the heat transfer capabilities of the latter goes some way towards validating a CFD package as a viable virtual prototyping method. In light of the results assumptions were established to allow the comparison of a duel channel radial and concentric clutch designs on a heat transfer basis.

An application of electrorheological (ER) fluid in ER clutch is considered. The clutch is embedded in a broader system with a driving machine on one side and a loading machine (brake) on the other. The quasistatic model of the system at a constant load and speed is described and solved in a dimensionless form. Efficiency of ER clutch is determined as the ratio of the output and input powers and consecutively analyzed in the space of model parameters. A special sensitivity analysis for many thousands of combinations of parameters (in their possible ranges) is performed and statistically evaluated. For some combinations of parameters and some arrangements of the system, efficiency can be greater than one due to additional energy originating from ER fluid. In such cases, more refined energy balance and definition of efficiency are needed.

In the paper an experimental device with upper half of a radial electro-structured fluid (ESF) clutch with vertical axis (consisting of a lower stationary disc and upper rotating disc) is examined for constant speed of rotation. The narrow gap between the discs is filled with a viscous liquid, so electro-structural effect is not taken into consideration. Frictional tangential forces in the fluid generate heat which is transferred through the fluid and rotating disc (by conduction) into surrounding air (by convection). A steady state model of heat transfer for the system in question in nondimensional form is built up and solved. Several novelties in approach and solution relative to existing ones are adopted and realized (described in detail in 5 appendices). Analysis of influence of the system parameters upon results of solution is given. For some particular cases theoretical results are compared with experimental ones by means of tables and diagrams and very good agreement is pointed out.