Namesti 1. kvetna 63, 664 34 Kurim, Czech republic
Tel.: +420 541 231 696, Fax: +420 541 231 272
www.sobriety.cz , info@sobriety.cz
Computations
Numerical simulations at present complement or completely replace a large portion of experiments and product tests. In the field of technical computing, we cover a wide range of disciplines, including the most challenging, which include fluid flow or aero-acoustics. Broad scope of expertise allows us to solve complex problems that require a multidisciplinary approach. Our solutions are based on proven commercial software and the latest computer hardware.
External aerodynamics
In the field of external aerodynamics mainly concentrate on computations of drag and lift forces acting on a body in the airflow, which supplement, or often even completely replace the experiments in aerodynamic tunnels. Greatest importance of this discipline is in the automotive and aircraft industry, but its application can be found also in construction industry. Optimization of shapes from aerodynamic perspective goes hand in hand with the trend of reducing energy losses of vehicles and thus lowering the environmental impact.
- Determination of drag and lift forces and coefficients of objects (vehicles, aircraft or their components)
- Optimization of components with regard of the previous point
- Simulation of non stationary events /processes behind flow around objects (influence of behind moving vehicles)
Internal aerodynamics
In the area of internal aerodynamics we concentrate on the flow of gases and liquids in confined spaces. In general cases, it is necessary to solve problems with medium compressibility, viscosity, turbulent behavior and other nonlinearities, which ranks the area to difficult subjects, not just to engineering applications. The aim of our optimization is usually to find a suitable channel shape for optimal gas flow, in order to meet defined requirements such as minimum pressure loss, maximizing the flow etc. We also provide optimization of flow in the space within motor vehicles with the aim of more efficient cooling and we suggest shapes of exhaust grilles in ventilation circuits of cars.
- Air intakes and exhaust gas outlets optimization
- Simulation of air flow in combustion engine compartments
- Air-condition systems and pipes flow
- Under-hood flow simulations (engine compartment flows)
- Mass flow optimization of channel shapes
- Air flow through heat exchangers
- Oil leakage flow analyses at rotational sealing parts
- Aerodynamic particle and air drop separator design and optimization
Thermodynamic calculations
Cooling / Heating
Proper heat dissipation from heat-stressed components increases their reliability. Thanks to 3D CFD calculations we are able to evaluate the sufficiency of the total exhausted heat and also the risk of local boiling. For cooling systems, we are able to design or optimize heat exchangers, while ensuring their proper supply with cooling medium. In the context of increasing demands for efficiency and economy of all the systems we also deal with the use of waste heat.
- Heat conducting in liquids, gases and solids
- Convection coefficients identification
- Evaluation of cooling efficiency of components, for example brakes
- Optimization of cooling air intakes
- Heat exchangers design and optimization
In-cylinder flow of combustion engines, turbines and turbochargers
Through optimization of flow in the combustion engines can be achieved a better filling of the cylinder or more efficient fuel combustion. Using non-stationary calculations we are able to perform in-cylinder shapes optimization of piston heads or valve seats, and thus reveal the hidden performance potential of the engine. Likewise we are able to suggest a more efficient flow through turbocharger and determine pressure on turbine vanes.
- Air intakes and exhaust gas outlets optimization
- Optimization of in-cylinder shapes of piston heads and valve seats
- Calculation of pressure distribution determination on turbine stator vanes
- Shape design of outlet diffuser and piping of turbocharger turbine
Radiation
Thermal radiation plays an important role, especially in cases of higher temperatures of radiating objects. The radiation occurs not only between the surfaces of solids, but depending on the contents of radiating particles or particles radiating through its volume also in gases. In the field of radiation we most commonly solve :
Example of use :- Heating resulting in sun radiation (for example heating of passenger space in cars, heating in buildings)
- Heating / cooling of surfaces through radiation (also in connection with convection and conduction)
- Exhaust gas radiation during flow and burning (for example radiation of combustion gases in turbochargers)
- Sun radiation through windows in various HVAC applications
Simulations with phase changes
Condensation
We perform simulations focused on air moisture management. Its utilization can be found wherever it is necessary to achieve certain air quality, such as the residential rooms or passenger room of cars. We can assess the risk of condensation and thereby prevent damage associated with its elimination.
Example of use :- Air-condition air moisture management
- Condensate accumulation assessment based on air moisture
Defrosting
Clear view from a car is essential for safe driving of any motor vehicle. Thanks to 3D CFD calculations can we are able to simulate the process of windows defrosting in a time period. Based on the results we are able to design appropriate amount and direction of air from the blowers and provide the driver with clear view in the shortest possible time.
- Windscreen defrosting speeding up
- Mirrors defrosting evaluation
Hot liquids and boiling
Boiling of liquids in closed systems can very negatively affect the strength and durability of technical structures and their corrosion. Uneven heat flow causes formation of thermo-galvanic cells and causes corrosion, especially where heat transfer causes a change between liquid and gas. By controlling the geometry of liquid channels with the aim to ensure adequate cooling, we can identify areas at risk of local liquid boiling.
Example of use :- Determination of heat transfer coefficients on a cavity and channel walls
- Local boiling risk assessment for cooling liquids inside channels and cavities of turbochargers
- Identifying minimal flow rate without the risk of cooling liquid boiling.
Soiling / Dusting
Multiphase computational models allow tracing the movement of small particles such as dust or water drops in the air. These calculations are widely used for example in the design of particle separators and defining the rate of filter chokes.
- Particle tracing in various liquids or water drops tracing in the air
- Filter chokes simulations
- Aerodynamic particle separator design and optimization
- Particle tracing in turbochargers to assess damage risk
- Car soiling analyses
Acoustics
Flow of liquids and gases in industrial applications is often accompanied by the emergence of unwanted noise. This is caused by slight pressure pulsations in the liquid, which usually bear several degrees lower energy than the actual flow. In the field of aero-acoustics we mostly predict generation and spread of noise induced by air flow.
- Noise generation and propagation due to the external flow (buffeting by opening side and roof car windows)
- Noise generation and propagation due to the external flow (whistling sound caused by external flow around narrow joints)
- Noise generated due to gas intake, for example to radial compressor
- Noise generated at liquid outlet through a nozzle
Optimization
For optimization of component parameters we use several methods, which allow us to determine the optimal settings for many, often conflicting, requests of customers. Sensitivity analysis and DOE methods implemented in the optimization methods are able to provide us with more comprehensive insight into the problem in question.
- Mass flow optimization of channel shapes towards the intercooler of compressed air
- Shape modifications for pressure losses minimizing
- Piping shape modification for pressure losses minimizing
FEM analyses
Many practical problems is of a multidisciplinary nature, when interaction of fluid and structural mechanics occurs. This interaction is realized by forceful action of the current field (flow pattern) on structural component and heat transfer from the current field to structural parts. In the FEM calculations, we solve current field exposure to changes in stressed structural components, and also the problematic of fatigue life. For validation we use experiments and contact and optical measurements that we perform at high temperatures up to 1200 ° C.
Thermo-mechanical analyses
We provide services in the field of design and development of components. Based on our knowledge of the distribution of temperature fields in a body we solve elasto-plastic analyses with the aim to identify critical points in structures. Analyses may also include the influence of creep impact, which will result in rendering the number of cycles to crack initiation in low cycle and high cycle fatigue. We also create a methodology for evaluation of plasticity and validate the use of contact and non-contact measurements.
The most frequently solved areas :- Static and dynamic analyses of structure distortion due to thermal pulsation
- Transient thermal analyses to determine critical spots
- Creep analysis
- Combined elasto-plastic analyses incl. impact of creep
- Plastic creep simulation (Thermal Ratcheting)
- Optimization of components to eliminate thermal stress
- Static and dynamic analyses of structure components from metal, ceramics and composite materials
- Fluid structure interaction (FSI) simulation
- Optimization of shape, weight, strength and deflection
- Stress-strain analysis with use of hyper-elastic models (elastomers, plastics, soft tissues)
- Measurement of material characteristics and evaluation of parameters of material models (Mooney-Rivlin, Ogden …)
- Analysis of residual stress in a body and converting the measurements to the actual stress and strain on the general objects considering plasticity
Fatigue and fracture mechanics
We provide calculations in the field of fatigue and fracture mechanics. We deal with methods of evaluating thermal fatigue and elimination of costs necessary to obtain parameters describing the fatigue model. For the experimental design of fatigue models parameter identification we use DOE methods in combination with accelerated testing. For validation we utilize non-contact optical methods of image analysis.
- Improved description of the fatigue model and its engineering implementation
- Design of samples for low-cost measurement of fatigue model parameters
- Design methodologies for evaluation of residual life cycles
- Validation of the methodology on real component
- Crack initiation and propagation analyses
- Determination of residual durability
- Analysis of fractured objects
- Suggestion of measurements against cracks initiation, eventually against crack propagation
- Optimization of the number of cycles to crack initiation