Non-Newtonian Bubble Suspensions
Lead Research Organisation:
University College London
Department Name: Chemical Engineering
Abstract
In this project, we will investigate the role of air entrainment on the rheology and processing of oral health products. The following tasks are planned.
Task 1 - Generation of bubble suspensions in Newtonian media. We will develop setups to introduce controlled amounts of air bubbles in liquids. Possible bubble generator setups will include microstructured membranes or microchannels connected to a pneumatic control system to generate the required amount of bubbles. We will also consider surfactants commonly used in oral healthcare products to study their effects and to increase the fraction of entrained air. Initially, the ambient fluid will be Newtonian. At a later stage of the project, we may consider non-Newtonian ambient fluids.
Task 2 - Rheology characterization. We will systematically study the theological behaviour of the mixtures from Task 1 using shear and elongational rheology tests in steady-state and transient (oscillatory) conditions. This will include flow curves, determining storage and loss moduli.
Task 3 - Details of bubble suspensions. The sizes and size distributions of the bubbles in the suspensions will be measured using imaging. We also plan to visualise the bubbles in flow either in a modified rheometer or in small channels to investigate their deformation and the relation to rheology. We will introduce the suspensions in stirred vessels or channels and measure the power requirements or pressure drop which will be related to the rheology of the suspensions. Depending on the conditions it may be possible to carry out velocity measurements in the continuous phase at various flow cases (flow in channels or in stirred vessels).
Task 4 - CFD studies. A CFD model may be developed using the rheology data from Task 2 to model the flow of bubble suspensions. Power (or pressure drop) measurements can be used for the initial validation of the CFD model. It may be possible to validate results against the velocity measurements.
Task 5 - Suspensions in non-Newtonian media. As mentioned in Task 1, at a later stage of the project we may investigate experimentally bubble suspensions in non-Newtonian media. Rheological tests will be carried out to characterize the rheology of the suspensions, while for some systems the power requirements (or pressure drop) in stirred vessels (or channels) will be measured.
Task 1 - Generation of bubble suspensions in Newtonian media. We will develop setups to introduce controlled amounts of air bubbles in liquids. Possible bubble generator setups will include microstructured membranes or microchannels connected to a pneumatic control system to generate the required amount of bubbles. We will also consider surfactants commonly used in oral healthcare products to study their effects and to increase the fraction of entrained air. Initially, the ambient fluid will be Newtonian. At a later stage of the project, we may consider non-Newtonian ambient fluids.
Task 2 - Rheology characterization. We will systematically study the theological behaviour of the mixtures from Task 1 using shear and elongational rheology tests in steady-state and transient (oscillatory) conditions. This will include flow curves, determining storage and loss moduli.
Task 3 - Details of bubble suspensions. The sizes and size distributions of the bubbles in the suspensions will be measured using imaging. We also plan to visualise the bubbles in flow either in a modified rheometer or in small channels to investigate their deformation and the relation to rheology. We will introduce the suspensions in stirred vessels or channels and measure the power requirements or pressure drop which will be related to the rheology of the suspensions. Depending on the conditions it may be possible to carry out velocity measurements in the continuous phase at various flow cases (flow in channels or in stirred vessels).
Task 4 - CFD studies. A CFD model may be developed using the rheology data from Task 2 to model the flow of bubble suspensions. Power (or pressure drop) measurements can be used for the initial validation of the CFD model. It may be possible to validate results against the velocity measurements.
Task 5 - Suspensions in non-Newtonian media. As mentioned in Task 1, at a later stage of the project we may investigate experimentally bubble suspensions in non-Newtonian media. Rheological tests will be carried out to characterize the rheology of the suspensions, while for some systems the power requirements (or pressure drop) in stirred vessels (or channels) will be measured.
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| EP/R513143/1 | 01/10/2018 | 30/09/2023 | |||
| 2339605 | Studentship | EP/R513143/1 | 16/12/2019 | 15/02/2024 | Stamatina Mitrou |