With his multidisciplinary team, Civil Engineer Majid Hassanizadeh is using experiments and computer simulations to develop new models for describing the flow of liquids and gases in porous materials. He has set up the Experimental and Computational Laboratory for Porous Media, which is already attracting interest from international companies and scientists. There are plenty of useful applications: oil fields, ink penetration into paper, tissues, filters and the release of methane gas from the frozen soils under the oceans. Hassanizadeh has even analysed the spread of injection of chemotherapy drug solutions in the brain.
From soil to other porous media
Geoscientist Hassanizadeh comes from Iran: "My original expertise is hydrogeology: the movement of water in the soil. I was then able to apply that knowledge to the contamination of groundwater by organic liquids. I went on to research liquids in oil fields and the consequences of storage of radioactive waste in deep geological formations on groundwater quality. Eventually I began to study porous media other than soils, for example fuel cells. Several years ago, I joined forces with Professor Helmig from Stuttgart to set up an international association for porous media. The experts from different sectors have hardly any knowledge of each other's work." There is still a lot to discover. "Existing calculation models take insufficient account of the interaction of several liquids with each other. In the current routine of 'reservoir engineering', they have to continually modify their calculations when oil field production does not match the estimates."
Chemical reactions at interfaces between fluids
Progress is possible in various areas "Most calculations are based on average quantities; averaged over thousands of very small pores. But the interactions between fluids and solid are often irregular. For example, in the case of a gas, it forms tiny bubbles. Here, we can analyse in real-time what happens when several liquids and gases permeate into the minuscule channels of a porous material. We can see that interactions occur at the interfaces between two fluids, which we can quantify using image analysis. This results in better estimates. You can also influence the behaviour of the two liquids at the interfaces and therefore also their dispersal within the porous material."
In the years ahead, the researchers will focus on such areas as the absorption of ink by paper and of liquid in nappies and the movement of various liquids in sand and hydrogen batteries. Experiments can be conducted through the use of a sandbox and in small porous disks in the lab. With a special camera set-up, the research team is able to image very fast movements of several liquids in small channels. Very few of these dynamic experiments have been conducted elsewhere. "We use a special high-resolution microscope. In this way, we are able to image the three-dimensional absorption of ink in paper or the movement of tiny colloidal particles within soil. We also make computer simulations. They are faster and can be used to measure the pressure in a pore or the surface area of the boundary between two fluids."
Hassanizadeh is focused on science "My main goal is: upgrading the lab and making Utrecht a place where scientists and industrial researchers come in search of new information about two-phase flow: the effect of several fluids on porous media. Old theories will then make room for new ones."
Written by: Youetta Visser