Effects of flow regime and geometrical parameters on the heat transfer in blow-by gases cyclone separators

The aim of this experimental study is to investigate the gas-to-wall heat transfer, as a function of the flow regime. The experimental set-up involves a flow configuration with a constant wall temperature. Simultaneous measurements of the flow rate and characteristic temperatures permit the determination of the average wall heat transfer coefficient through an enthalpy balance. Static pressure fluctuation intensities have been carried out, and we use these measurements to identify the change in the flow regime from laminar to fully turbulent. We varied the inlet Reynolds number, and the geometry of the cyclone. An average Nusselt number correlation for the evaluation of the heat transfer in a cyclone is proposed for inlet Reynolds number Re-i ranging from 400 to 20 000, and for different values of the dimensionless geometrical parameters L* (0.75 <= L* <= 2.25). Pressure drops are also measured and compared to those obtained by application of available models.