Research

Multi Phase Flows and Heat Transfer - AAU Energy research group

Research

Ongoing PhD projects:

Bhavik Rajitram Barai

Kasper Gram Bilde

A wet scrubber is commonly used in the marine industry to remove sulphur and particulate matter from the engine exhaust gas. When the scrubber is operating in a closed-loop mode, the water is recirculated over the scrubber and therefore needs continuous cleaning to remove the particulate matter before being discharged into the Oceans and also to prevent clogging of sprayers. To reduce the time needed to separate the particulate matter from the water, agglomeration of the particulate matter is beneficial. The aim of the PhD study is to develop a numerical model describing the dilute particle-laden flow where particles can collide, agglomerate and break up. By successfully describing the multi-physics of the liquid-solid system, particle aggregates in a shear flow can be investigated which will be used for predicting and optimising particle aggregation and sedimentation applications. The multiphase model is developed using the open-source computational fluid dynamics application OpenFOAM.

Nick Høy Hansen

Different processes are today used onboard marine vessels to remove toxic gasses from the exhaust gas; however, large quantities of particle matter are still being discharged to the environment every year. To access this problem a wet electrostatic precipitator (ESP) can be used to remove the particles from the exhaust gas before being discharged. To minimize the wet ESP system and the time needed to separate the particles from the exhaust gas, particle charging, and forces applied to the different phases of the system are of great interest. The aim of the PhD study is to build a large-scale wet ESP system for a marine engine and develop a numerical model describing the different phenomena inside the system. By successfully describing the multi-physics of the electrostatic-gas-solid system, the particle migration from the gas-phase can be investigated which can be used for predicting and optimisation of the particle removal inside a wet ESP system under different conditions. The wet ESP model is developed using the open-source computational fluid dynamics application OpenFOAM.

Ali Yahyaee Nujukambari

Although thermally driven phase change phenomena have an essential role in largeā€scale and small-scale applications as an efficient heat transfer mechanism, their simulation is still in its infancy. One of the main challenges in CFD modeling of two-phase flows is locating the interface position. Default formulation for simulating phase change uses the Volume Of Fluid (VOF) method as the interface description method. The main drawback of VOF is the smearing of the interface and the difficulty in obtaining sharp interfaces between the phases, which may lead to spurious flows and inaccurate results. In this project, to avoid smeared interfaces and have accurate results in the simulation of thermally driven phase change phenomena, Ali will extend a new formulation (a solver in OpenFOAM) for their CFD simulation, being capable of using two more accurate interface description methods (CLSVOF and isoAdvection) and adaptive mesh refinement.

Finished PhD projects:

Anders Schou Simonson (2019):
Modelling and Analysis of Seawater Scrubbers for Reducing SOx Emissions from Marine Engines.

Marie Cecilie Pedersen (2018):
Modelling Icing on Structures for Wind Power Applications

Anna Lyhne Jensen (2018):
Characterisation of Rag Properties and their Transport in Wastewater Pumps

Jakob Hærvig (2017):
On the Adhesive Behaviour of Micron-sized Particles in Turbulent Flow: A Numerical Study Coupling the Discrete Element Method and Large Eddy Simulations.