In his research, Göran Tuomas, who will defend his thesis titled Water Powered Percussive Rock Drilling—Process Analysis, Modeling, and Numerical Simulation on December 20, has addressed several different processes and problems presented by water-powered rock drilling. The function and rock penetration process for the drill itself have been analyzed, modeled, and simulated, which means that the performance of the machine can be studied even before it is manufactured.
The computer models also offer enhanced capacity to assess the quality of the rock during drilling, since the dynamic behavior of the machines is dependent on the mechanical properties of the rock. In this way the computer has become an important tool in developing, optimizing, and using these machines.
This research work has also resulted in a new measurement laboratory and in a number of new products and prototypes. An absorber for equalizing variations in pressure in the feed water of the drill has been developed using carbon-fiber/epoxy material in collaboration with the Sicomp company in Piteå.
This choice of material provides low weight and high rigidity, a prerequisite for absorbing very rapid pulses of pressure.
Another product developed is a dumpster-based machine for separating the crushed rock from the drilling water and for pumping the high-pressure water to the drill. This machine makes it possible to recycle the polluted drilling water, which reduces the use of water and emissions during operation. Here, too, the computer was used as a tool in developing the product, in that the process of particle flow in a system with this machine was modeled and simulated.
“My dissertation also presents new thinking about drilling techniques in connection with geothermal heating systems,” says Göran Tuomas.
“The idea is based on the fact that heat is generated in drilling, which leads to the rock around the drill hole being warmed up. By determining the amount of heat produced, it is possible to estimate the heat conductivity of the rock directly during drilling, which enables us to dimension the geothermal system dynamically.”