金涌, 俞芷青, P.N.Rowe D.J.Cheesman. On the Bed Collapse Technique for Measuring Dense Phase Voidage of a Gas Fluidized Bed[J]. CIESC Journal, 1988, (2).DOI:
Dense phase voidage can be estimated by cutting gas flow and following the rate of bed collapse. Abrupt cessation of flow is not possible when excess gas in the wind box can only discharge through the bed. The magnitude of this problem is examined experimentally.