TURBULENT-FLOW BETWEEN 2 DISKS CONTRAROTATING AT DIFFERENT SPEEDS

This paper describes a combined computational and experimental study o f the turbulent flow between two contrarotating disks for -1 less than or equal to Gamma less than or equal to 0 and Re-phi approximate to 1 .2 x 10(6), where Gamma is the ratio of the speed of the slower disk t o that of the faster one and Re-phi is the rotational Reynolds number. The computations were conducted using an axisymmetric elliptic multig rid solver and a low-Reynolds-number k-epsilon turbulence model. Veloc ity measurements were made using LDA at nondimensional radius ratios o f 0.6 less than or equal to x less than or equal to 0.85. For Gamma = 0, the rotor-stator case, Batchelor-type flow occurs: There is radial outflow and inflow in boundary layers on the rotor and stator, respect ively, between which is an inviscid rotating core of fluid where the r a;dial component of velocity is zero and there is an axial flow from s tator to rotor. For Gamma = -1, antisymmetric contrarotating disks, St ewartson-type flow occurs with radial outflow it boundary layers on bo th disks and inflow in the viscid nonrotating core. At intermediate va lues of Gamma, two cells separated by a streamline that stagnates oil the slower disk are formed. Batchelor-type flow and Stewartson-type fl ow occur radially outward and inward, respectively, of the stagnation streamline. Agreement between the computed and measured velocities is mainly very good, and no evidence was found of nonaxisymmetric or unst eady flow.