Research Activities

Research Report 2013The Wessex Institute of Technology continues to be very active in research covering a number of specialised fields including environmental and electromagnetics, ecology, fluid mechanics, corrosion, damage and fracture, damage tolerance and many others.

There are several divisions involved in both industry and EU funded projects of which typical examples are as follows:

 

 

 

Antibacterial and Antifungal Medical Textiles based on a SONO chemical process (SONO)

sono
The pilot plant produced by CEDRAT, France, using piezoelectric transducers.

SONO is a large scale integrated project involving 17 institutions from Europe. It is part of the European Commission 7th Framework Programme and it is focused on the application of nanotechnology in medicine. The project’s duration is 48 months. The main objective of this project is to build a pilot line based on the sonochemical process to produce biocidal textiles by impregnating fabrics with antibacterial nanoparticles. The design of the pilot sonochemical reactor is aided by employing computational modelling, which is the main task of the Environmental Fluid Mechanics Division at WIT. The developed models are used for optimisation of the pilot line and the design of a full scale production line.


 

reactor
Reactor’s cross section showing mixing in the reactor due to acoustic streaming and mechanical mixing (the white bar represents one of the transducers).
Reactor Model

The project includes modelling of the mechanical mixing, species transport with reaction and heat transfer in a sonoreactor. The effects of acoustic streaming are included in the model together with the mechanical mixing due to fluid recirculation supported by a pump. The results obtained from these studies provide crucial information for the understanding of the various processes taking place simultaneously inside the reactor. This information is further used for reactor’s operation optimisation.


 

Propogation of Acoustic Waves in Bubbly Liquid

When acoustic waves propagate in bubbly liquid, there is a damping of the waves, which in this case has been modelled by introducing a complex wavenumber in the Helmholtz equation. Understanding how the acoustic waves propagate inside the sonochemical tank provides information on the active cavitation zones that are crucial for the sonochemical reaction.


 

Multiple Bubble Dynamics

Cavitation in liquids is a very important phenomenon which can be considered as a means for energy concentration in the liquid. The collapse of the bubbles can be so rapid that temperatures of thousands of degrees Kelvin and pressures of thousands of atmospheres can be achieved. Such high pressures and temperatures can help the chemical reactions.

Modelling of the bubble dynamics is a moving boundary problem where the interface between the liquid and the gas changes very rapidly. The numerical solution is based on the boundary element method as only the gas-liquid interface needs to be taken into account.

bubbles


 

Exposure of the Human Eye to HF Electromagnetic Field with respect to Thermal Effects

This research involves the developement of efficient methods and codes for the calculation of high frequency electromagnetic fields in lossy media such as human tissue. These codes help us understand certain often overlooked effects, such as the effect of EM fields in the eye at frequencies lower than those present in the visible range. This investigation has identified the focussing effect of such radiation which causes ‘hot spots’, that is temperature gradients that exceed agreed standards.


 

“Life Span Prediction of Hydraulic Turbine Rotors” in collaboration with the University of Sulainmani (Iraq)

Velocity1The project requires 3D simulations of water flow in the Francis turbine runner for different operating conditions combined with stress analysis with the aim to identify possible crack locations in turbine blades.

The pressure distributions on the runner are obtained from this analysis and the results for different boundary conditions are incorporated into a FEM model to calculate the stress distributions. The results indicate that the maximum stresses are situated at the transition between the blades and the crown on the trailing edge, which is verifi ed by the appearance of cracks in these areas.

The models were used for synthetic data generation of the vibration of the turbine runner. The changes in the vibration of the turbine runner were analyzed using the principal component analysis (PCA) combined with artificial neural networks (ANN) and multiple adaptive neuro-fuzzy inference systems (ANFIS) in order to identify the size and position of the crack.