Abstract
The influence of cross-flow velocity and transmembrane pressure on the optimal back-shock frequency and normalized net flux during back-shocking has been studied using a semi-analytical mathematical model. The model uses the flux as a function of time without back-shocking together with knowledge of the streamlines and pathlines during the back-shock cycle to predict the optimal normalized net flux as a function of forward filtration time. The model was used to investigate three different transmembrane pressures and three different cross-flow velocities during a back-shock cycle. The net flux was found to increase under all operating conditions when using back-shocking. The greatest increase in normalized net flux was found at the highest cross-flow velocity and the highest transmembrane pressure, and corresponds to an increase of 37% compared to the steady-state flux. The highest cross-flow velocity and the highest transmembrane pressure gave the highest optimal back-shock frequency of 0.21 Hz. The optimal back-shock frequency was found to decrease with increasing pressure and decreasing cross-flow velocity.The model is easy to use in different applications as it is easy to measure flux during forward filtration without back-shocking. Good agreement was found between the semi-analytical model and a model based on computer fluid dynamics in predicting both the value of the optimal normalized net flux and the optimal back-shock frequency.
| Original language | English |
|---|---|
| Pages (from-to) | 137-143 |
| Number of pages | 7 |
| Journal | Journal of Membrane Science |
| Volume | 506 |
| DOIs | |
| Publication status | Published - 2016 May 15 |
Subject classification (UKÄ)
- Fluid Mechanics and Acoustics
Free keywords
- Back-shock frequency
- Back-shocking
- Mathematical modelling
- Net flux
- Semi-analytical model
- Ultrafiltration