Damping element to reduce noise caused by steam venting
With power generators, it is sometimes necessary to vent steam to reduce pressure in the system. This venting is done through a device that consists of a safety valve and muffler. The muffle’s primary function is to reduce the pressure in the system to permissible levels. Due to highly turbulent changes during this process, acoustic emissions are generated. If the muffler is located close to populated areas, it is necessary to reduce the level of acoustic emissions as much as possible to a level permitted by health standards. The noise generated in the muffler can be predicted using CFD simulations and reduced through design optimization.
Today, conventional air-cooling of disc brakes occurs by ventilated and perforated discs. These brake systems attempt to maximize the heat transfer surface area through the shape of the brake’s disc. GCS braking systems are additionally equipped with a special cover (diffuser) that utilizes the air’s kinetic energy at the disc’s outlet and drives the cooling air through the disc (through transverse holes) one more time to increase cooling effect. With brakes, cooling is a priority because even the best friction materials have temperature limits. In addition to its cooling function, the diffuser also performs a protection function and protects brakes against the effects of abrasive particles such as water, snow, salt, dust, etc.. This extra protection further increases the efficiency and service life of brakes. GCS braking system is a new concept suitable mainly to racing cars, where extreme need for brake system cooling is requested. The system is suitable for application with steel, carbon or carbon/ceramic disc brake systems. This system was initially developed for Formula 1 racing cars, but it can also be applied for cars in general.
Research and development of a “G-Cooling System” (GCS) braking system
A sensor for measuring the temperature of motor flue gases
The main criteria in designing a sensor for measuring the temperature of exhaust gases are accuracy and the shortest possible starting time. Thermodynamic CFD simulations have enabled developers to make a number of calculations that have made it possible to design a sensor that meets the respective requirements. The proper design of such sensor with a short starting time requires the developers to know the heat-transfer coefficient between the sensor and circumfluent exhaust gases. Using conventional methods based on previous experience and experimental measurements to determine precisely this coefficient is very expensive and time consuming. Mathematical modelling and high performance computing systems, however, can significantly speed up the entire process and thus substantially reduce the costs associated with development.
When solving orthopaedic problems, it is important to know the mechanical properties of bones. These are mainly given by their complex internal structure that can be determined using computer tomography. The manner in which knowledge about the mechanical properties of bones is discovered is as follows: based on computer tomography results and known properties of individual components, it is possible to create a mathematical model of a representative volume that can be used for simulating various types of load and counting responses. This replaces conventional mechanical tests of materials that are destructive and therefore impractical. The use of mathematical modelling and high-performance parallel computing techniques together with computer tomography allows for the analysis of mechanical properties and the optimization of materials with complex internal structures.
To improve the strength of rock structures, we can use grout made from various substances, including polyurethane resins. The properties of a composite material (geocomposite) can be studied by creating a mathematical model of a representative volume and applying various types of loads to it. Thus, we can also look for the most suitable resin composition, determine its sensitivity to changes in composition, assess grouting technologies, etc. The use of mathematical modelling and high-performance parallel computing techniques together with computer tomography, allows for the analysis of mechanical properties and the optimization of materials with complex internal structure.
This discipline mainly focuses on flow in porous media in relation to mechanical deformation. This problem is prevalent in geomechanics in the use of underground oil and gas fields, as well as in the underground storage of carbon dioxide. Another area includes the sealing of underground spaces that are necessary, for example, for the underground storage of spent nuclear fuel. In this respect, the Research Program team at the Institute of Geonics is taking part in the international Decovalex project (short for “Development of Coupled Models and their Validation against Experiments”) and in the modelling of SEALEX experiments (the long-term monitoring of the sealing ability of swelling bentonite) in the experimental minitunnel (60 cm in diameter) in the Tournemire underground laboratory in southern France – see the figure. In this experiment, the modelling involves unsaturated flow in bentonite as well as the surrounding rocks and the mechanical response involving plasticity, swelling, changes in the pore space and other relatively complex and non-linear effects.
Solving problems of multiphysics
(fluid flow and mechanics)
Tuning of shock absorbers and mapping their movements
In mechanical systems, we encounter vibrations that are transmitted from the surroundings to the given piece of equipment. Such vibrations are generally undesirable and may even cause damage to a mechanism; they must therefore be dampened. One way of doing so is to install a shock body that absorbs energy and thus dampens the vibration of the entire system. Although this idea is simple, it turns out that finding the correct damper setting is a difficult engineering problem. The model is extremely sensitive to initial conditions, particularly to resonance frequency. Therefore, simulations give us a powerful tool to locate bifurcation boundaries for which the total vibration is minimal, and allow us to study trajectories that can be periodic, quasi-periodic or even chaotic. Using appropriate simulations, we are able to find the perfect damper setting and determine the mass of shock bodies, spring stiffness or gap width of the dampener’s clearance.