The rate of deposition on the manifold wall of liquid droplets from the multi-component, two-phase stream of fluid flowing in the inlet manifold of a carburetted petrol engine and the re-entrainment of droplets into the stream from the liquid film which flows on the walls have been investigated using a single cylinder crossflow engine. The effect of throttle opening, straight manifold length, a smooth bend and a mitre bend is reported: measurements of exhaust emissions and cycle-to-cycle pressure variation of cylinder pressure are related to wall film quantities. It was found that throttle position was important in determining the initial wall film, that the average thickness of the film decreases with length along the straight manifold and that droplet re-entrainment from a sharp bend is greater than from a smooth bend. Removal of the wall film yields a significant reduction in the emission of unburned hydrocarbons and virtually eliminates cycle-to-cycle variations of pressure in the engine cylinder.

The present paper reports the correlation between the predicted performance and experimental data obtained from a hydrostatic thrust bearing under conditions designed to produce phase change due to viscous dissipation within the lubricant. The predicted values of pressure distribution indicate that the best correlation is obtained when the viscosity of a two-phase mixture is assumed to be the volume average of the viscosity of the individual phases.

SummaryTypical performance characteristics are presented for a cascade of two-dimensional bluff aerofoils employing circulation control from a tangential blowing jet. The cascade was tested in various configurations at a freestream Mach number of 0·3 and Reynolds number of approximately 1·5 x 105. Lift and drag coefficients and stream deflection are related to the blowing jet momentum coefficient. The expressions employed for lift and drag eliminate the direct effect of the blowing jet on measured performance, which was found to be influenced strongly by vortex shedding at low jet blowing rates.For the configurations employed, tests showed that the economical application of circulation control on an uncambered blade could produce flow turning angles up to 20°.

SummaryThe procedure described applies to aerofoils or cascades with circulation controlled by tangential blowing jets and provides a complete numerical solution for aerodynamic performance in incompressible flow conditions.The pressure distribution over the blade surface is predicted by a potential flow model in which the region of separated flow is represented by an appropriated source distribution. Boundary layer development is calculated by a finite-difference solution of the parabolic boundary layer momentum equation: the development of the blowing jet and its mixing with the boundary layer over the curved trailing edge is predicted by the same procedure applied to an angular momentum equation, using an intermittency representation of the eddy viscosity distribution.Predictions are compared with experimentally measured lift coefficients for an isolated aerofoil, with turning angles for a cascade tested by other workers and with experimental turning angles for a cascade tested by the authors. The agreement between theory and experiment is good.