This project’s objective is to bring unique experimental insight to the detailed interactions between a gas and dispersed particles. By informing recent theories for those interactions, notably those of Profs. Brady and Koch, this work will benefit a wide array of industrial processes involving gas-solid suspensions.
The research is made possible by our development of a unique experiment producing shearing flows of gas and solids in the absence of gravitational accelerations. The facility will permit gas-particle interactions to be studied over a range of conditions where the suspension is steady and fully- developed. Within that range, we shall characterize the viscous dissipation of the energy of the particle fluctuations and record the dependence of the mean drag on granular agitation.
We are developing a microgravity flow cell in which to study the interaction of a flowing gas with relatively massive particles that collide with each other and with the moving boundaries of the cell. Unlike Earth-bound flows where the gas velocity must be set to a value large enough to defeat the weight of particles, the duration and quality of microgravity on the Space Station will permit us to achieve suspensions where the agitation of the particles and the gas flow can be controlled independently by adjusting the pressure gradient along the flow and the relative motion of the boundaries.
After a literature review, this second annual report describes the new axisymmetric experimental apparatus that we have designed for this project, and it outlines theories that we will employ for the interpretation of its data.