Drag coefficient for particles in rarefied, low Mach-number flows

From international symposium on two-phase systems; Haifa, Israel (29 Aug 1971). See CONF-710836-. A parameter essential to the quantitative analysis of two-phase flows is the drag coefficient of the condensed phase particles. A review of the published drag data reveals that no results are available in the important flow region delimited by Mach numbers less than 2 and Reynolds numbers less than 100. A microballistic range was developed and utilized to measure particle-drag forces in this flow region. The results, reduced in terms of a normalized drag coefficient, are correlated with other drag data available over a wide range of flow conditions. Finally, an algebraic equation which provides a good data fit for all Mach numbers and for Reynolds numbers less than the critical Reynolds number is presented. (auth)