Thermophoresis and its effect on particle impaction on a cylinder for low and moderate Reynolds numbers

The effect of thermophoresis on the impaction particles a cylinder is investigated for different particle sizes, conductivities, temperature gradients and Reynolds numbers between 100 1600. This first such study performed using Direct Numerical Simulations (DNS), where all temporal spatial scales fluid are resolved. Pencil Code, high-order finite difference code with an overset-grid method precisely simulating flow around cylinder. ratio impacting to number inserted upstream used calculate efficiency. It found that both conductivity gradient have close linear influence efficiency small particles. Higher result in higher middle-sized particles, while smaller In general, it only has larger dominated by inertial impaction. An algebraic model presented predicts thermophoretic force developed based fundamental principles validated against DNS results, which faithfully reproduced. As such, this can be understand mechanisms behind deposition due force, and, more importantly, identify means rate reduced. relevant example order minimise fouling super-heater tube bundles thermal power plants.