Topics in Low Re flow: From Microfluidic Fluid-Structure Interactions to Proppant Transport in Hydraulic Fractures

Date
12/2/2016
Location
11:30AM at REC 121
Speaker
Ivan Christov, Purdue University
Title
Topics in Low Re flow: From Microfluidic Fluid-Structure Interactions to Proppant Transport in Hydraulic Fractures
Host
Peijun Li
Description

In this talk, I will summarize some recent results from and new research directions for my research group. The first topic is from the field of microfluidics, in which rectangular channels with deformable walls are used as one of the simplest models for lab-on-a-chip devices. Experimentally, these devices are found to deform into a non rectangular cross-section due to fluid--structure interactions. These deformations result in a non-linear relationship between the volumetric flow rate and the pressure drop, which we seek to predict. Via perturbative calculations, the flow rate--pressure drop relation can be obtained by analyzing a coupled system of Stokes ($Re=0$) flow in a three-dimensional (3D) rectangular channel with a top wall that is linearly elastic, specifically a Kirchhoff--Love plate. We have recently benchmarked and verified the theoretical predictions by 3D numerical simulations, calibrated with experimental pressure drop--flow rate data, using the commercial software suite ANSYS. The second topic addresses some new ideas about controlling particle migration using geometry and hydrodynamics. Particle migration in flows is a phenomenon common to many areas of the engineering sciences, specifically in predicting how proppants are deposited into hydraulic fractures. Fracking involves the use of not just clear fluids but also fluids bearing proppants, which are particulate materials meant to settle into cracks to prop them open, prevent crack localization instabilities and increase fracture conductivity. There still remain fundamental aspects to particle migration in flows that are not fully understood. I will discuss some open problems, specifically related to formulating a transport problem for proppants and understanding how nonuniform conduit shapes and nonuniform hydrodynamic forcing could be exploited to preferentially control particle migration.