Rim Sealing of Rotor–Stator Wheelspaces in the Absence of External Flow

Sealing of the cavity formed between a rotating disk and a stator in the absence of a forced external flow is considered. In these circumstances the pumping action of the rotating disk may draw fluid into the cavity through the rim seal. Minimum cavity throughflow rates required to prevent such ingress are estimated experimentally and from a mathematical model. The results are compared with other workers’ measurements. Measurements for three different types of rim seal are reported for a range of seal clearances and for rotational Reynolds numbers up to 3 × 10⁶. The mathematical model is found to correlate the experimental data reasonably well.