Merry Christmas! The time has finally come, and Joy is best when it is shared. Therefore, we wish you a little peace, enjoy the days with your family and recharge your batteries.
But before, you might be interested in our “GAMMA” R&D project, a joint effort by @FRIENDSHIP SYSTEMS, @MTU Friedrichshafen, the @Technical University Darmstadt and @NUMECA Ingenieurbüro over a period of 3 years. In a dedicated workshop you can get some exclusive insight into efficient geometry parametrization, (structured!) CFD-workflows and fully coupled optimization of several turbocharger components. An advanced method for the full design chain is shown, tackling various challenges like aerodynamic performance, structural reliability and manufacturing feasibility. Shout-out to all our partners!
It’s nearly x-mas. Let’s see, what’s behind door number 23?
Extending quadcopter drone flight time and range with OMNIS™ CFD simulation
For multi-copter electric drones, maximum flight time and range remain to be one of the most important issues to address. The aerodynamic simulation and optimisation of the industrial quadcopter drone (UAV) were performed in hover mode, the most energy-intensive mode of this type of drone. The presented case demonstrates a set of powerful capabilities of OMNIS™, such as the combination of structured and unstructured meshing techniques and high-fidelity unsteady simulations using the Nonlinear Harmonic Method. Fully automated optimisation, based on efficient evolutionary algorithms, parameterisation and morphing, ensure a fast and robust workflow and an optimum design result for the defined objectives, such as maximising flight time and range.
December 22. Let’s see what’s behind today’s door.
Lowering fuel consumption through Robust Design Optimisation (RDO) of ship propellers
An optimised propulsion system (ship + propellers) is key in the shipping industry, as it has a direct impact on operational costs and fuel consumption. Traditionally, optimisation is done in a deterministic way, which is a simplification though. In real-world, geometries are not perfect as they are subject to tolerances, and the operating conditions vary a lot as well. Robust design optimisation (RDO) considers all these uncertainties in the optimisation loop and allows to optimise not only for a deterministic optimum, but also for ideal mean values and their standard deviations (and even more) – leading to reliable and robust products.
Coming back to the propeller: see our method applied on a real case here
December 21. Let’s see what’s behind today’s door.
Design Choices & Templates for Mesh Automation in OMNIS™
How can a simple automation for the study of geometry variation look like in OMNIS™?
We provide the answer here: We show you how to use Python to automate the process from geometry import to meshing and how to work efficiently with templates in the GUI. From partial to full automation in batch mode, everything is possible. The choice is entirely yours.
It’s December 20. Let’s see what’s behind today’s door.
Design and analysis of a centrifugal compressor for refrigeration cycles
One of our most recent projects was initiated by a request from a new customer, Teqtoniq GmbH . The objective: Establish an efficient workflow to design a turbomachine for a refrigeration cycle from scratch, that is from the velocity triangles to a final 3D design. To accomplish this goal, a test case was designed by means of CAE software provided from Cadence and Concepts NREC . This article will briefly describe the methodology and summarize a few numerical results from this preliminary design.
The first candles are being lit… first one, then two, then three, then four!
A wonderful fourth Advent Sunday to everyone and let’s see, what’s behind door number 19?
Design and Optimisation of an Inline Pump for Marine Applications
Pumps in vessels face various challenges: durability and ease of maintenance are a key cost factor, while space confinements demand small overall pump dimensions, including suction and pressure ducts. An interesting configuration is the so-called inline type, where both ducts share an axis, perpendicular to the centrifugal impeller shaft. However, such twisting and bending of a flow channel normally comes with a cost in terms of efficiency and head, plus higher risk of cavitation.
German pump experts at @Allweiler GmbH evaluate NUMECA for their CFD and optimisation tasks: a centrifugal pump is re-designed to an inline configuration and optimised!
Naturally, it would be favorable to consider seals and cavities during the CFD simulation of turbomachinery – but the meshing setup… For axisymmetric geometries the usage of a meridional effect, NUMECA internally also called ZR-Effect can make life and the meshing significantly easier. Seeing how a labyrinth seal is meshed (structured!) within a few minutes!
Toyota Motorsports optimises their already high-performing turbocharger components closer to perfection with FINE™/Design3D.
In this multi-disciplinary optimisation, Computational Fluid Dynamic (CFD) and Computational Structural Mechanic (CSM) simulations are considered to guarantee that changes in shape do not lead to unacceptable high stress levels. All aerodynamic targets are fulfilled and the structural integrity is also ensured. The results of the optimisation are very satisfactory:
1. Efficiency increase by up to 1.4% (percentage points) 2. Up to 8.0% higher total pressure ratio 3. Maintaining the chocking mass flow 4. Extension of the surge line up to 5% 5. Von Mises stresses are below limit
Let’s set sails and see, what’s behind door number 16?
Overset Grids and Adaptive Grid Refinement (AGR) for Marine Applications
These two techniques allow very realistic and efficient simulations: overset grids remove all limitations for body motions, for example controlled rudders or ships in heavy sea. AGR on top ensures a locally fine grid in the interpolation zones, increasing accuracy with minimum extra CPU costs. Also, AGR can capture relevant flow features like strong gradients or the free surface position, and the mesh will follow in space and time.
Furthermore, they are also easy to use thanks to the CWizard. In our lifehack we show some main applications and how to get you started:
Online CFD Course ends with Rocket Science. It was a pleasure seeing the great interest of so many students in the 2021 version of the Online CFD Course with Omnis™. In the final class the attendees simulated a launch vehicle traveling at Ma=1.5. We wish them all the best in applying their newly gained knowledge in future CFD projects. Follow us here on LinkedIn to stay in touch or sign up to our reminder mail to be on time for the 2022 edition:
Need to run a Contra-Rotating Open Rotor overnight? Unsteady of course!
Then our Nonlinear Harmonic (NLH) method is your tool that saves you a factor of 1.000 in CPU time compared to a classic unsteady approach. This frequency-based method is applied to the contra-rotating rotors, the engine pylon and the fuselage, modelling the fully unsteady interactions between all components for performance prediction or even as an input for acoustic simulations.
And for the halftime show we bring you this year’s CFD Marine workshop: a potpourri of contributions from partners like Friendship Systems, customers as MMG and academic users like Federal University of Rio de Janeiro. A lot of applications and methods were covered, small powerboats, electric ferries, offshore structures, optimisation and parametrisation – a big shout-out to all speakers! And to the almost 100 participants.
Ahh, some unsteady CFD + FSI (fluid-structure-interaction) on a radial turbine, performed by our long-year customers and turbomachinery experts at University Stuttgart. A fully structured mesh and the frequency-based NLH method allow for impressive turnaround times for such simulations – without compromising accuracy. And of course, proven by experimental data.
Unbelievable, how fast the time goes by. It’s December 10. Let’s see what’s behind today’s door.
In the race to more environmentally friendly electrical aircrafts, Pipistrel designs a propeller specially adapted for exploiting in-flight power recuperation using CFD optimisation. They use the propeller as an airborne wind turbine, by transforming the energy created during the descent of an aircraft into electric energy and storing it in a battery. The performance of the propeller design is numerically computed with OMNIS™/Turbo.
The results are:
– The aircraft consumes 6% less energy during the climb. – Net energy consumption during ascent/descent manoeuvres decreases by 19%. – A 27% increase in number of traffic pattern circuits is achieved.
Interested in more details? Here you can get the whole case study
Today we evaluate the wind loads on a Slender Vessel. DAMEN and Cadence Computational Fluid Dynamics developed a CFD methodology to proof a vessels capability to resist over-rolling in severe side winds. A numerical wind tunnel mimics the validation normally done in an experimental way, ranging from unsteady RANS simulations up to DES methods to ensure the necessary accuracy: a side-by-side comparison shows very good agreement between experiment and CFD. The latter can be expanded easily to full scale though, and it is also found to be more cost-efficient.
Maybe our design tools are exactly what you are looking for. Take a minute to get a first impression or have a closer look at one of our Lifehacks regarding “Intuitive Design of Turbomachines”. Whether you are interested in axial or radial, turbine, pump, fan or compressor. We have a design tool for every turbomachine.
Today we watch OMNIS™/AutoSeal in action in this short demo of the Honda CR-V geometry preparation (courtesy of Honda).
Poor quality CADs and highly complex geometries lead to long preparation and set-up time and the need for a lot of manual input to result in a good quality mesh. AutoSeal technology automates this entire process, without losing any detail of the geometry, and delivers quality meshes ready for CFD analysis.
HONDA testifies a major breakthrough in meshing speed with Cadence AutoSeal and OMNIS™/HEXPRESS.
Shoes out, socks out – St Nicholas comes. And while we are waiting for Santa to come, we glimpse behind door number 6!
Today, we see the opening of dual-disc check valves. The opening of the check valves is mainly caused by the hydraulic forces, acting on the discs. A dual-disc check valve relies primarily on the spring force for closure. Here, the transient flow through a typical valve is investigated in FINE™/Marine, and the opening process of the valve is analysed.
The first candles are being lit. First one, then two …!
A wonderful second Advent Sunday to everyone and let’s see, what’s behind door number 5?
Structured grids, such as those from AutoGrid, tend to follow the flow direction for numerical accuracy. For the sake of simplicity, unstructured grids mostly utilise a cartesian background mesh, which is flexible in usage and still provides good mesh quality. Still, unstructured grids can often be improved with only minimal extra effort via the usage of an adapted background mesh. This way, unstructured grid lines can be aligned with the main flow and hence achieve almost structured-grid mesh quality.
How about a cylindrical mesh? Or something fancier? Check our latest lifehack and see what you can do in OMNIS™.
Sci-Fi-Fans surely recognise the Colonial Viper fighter from the TV series Battlestar Galactica. Shown is the original design versus an optimised one in various stages of re-entry, focusing on performance and vessel stability.
The whole CFD and optimisation process is a well-developed workflow by Masten Space Systems, using NUMECA tools for parametrisation, meshing, solving and design optimisation. It’s fully adapted to HPC environments and considers aerodynamic performance, control, loads and aerothermal heating, with simultaneous trajectory optimisation. At Masten, these tools allow to increase reusability and hence decrease launch costs, while also improving the ecological footprint. Not just on the Colonial Viper.
If you like more details, follow the link and read on.
Today, we have a look at the fully-coupled fluid-dynamic simulation of a complete gas turbine engine done by @NUMECA is now Cadence. The analysis was comprised of a single fully-coupled 3D CFD simulation of the flow of a KJ66 engine redesign. A simplified flamelet model is used to model the injection and burning of fuel inside the combustion chamber. Using advanced RANS treatment with inputs from the Nonlinear-Harmonic (NLH) method (available as a module for OMNIS™/Turbo), tangential non-uniformities are captured and the flow physics of the interaction between compressor, combustor and turbine are assessed.
If you like more details, follow the link and read on.
Yesterday we promised a CFD Advent Calendar. So let’s see, what’s behind door number 2?
Today we have a close look at propulsion modelling using an actuator disk in marine applications. To spice it up, we included some oblique waves and a rudder controller. The actuator disc is a simplified propeller model and very cheap from a computational point of view, though it already accounts for some propeller-hull interaction (and appendages and rudders as well if you like). This makes it ideal for very realistic and complex simulations like seakeeping.
For details on our actuator disc, you can check out Rodrigo Correa’s life hack.
Christmas is approaching. Nothing in the world is as powerful as an idea whose time has come. We like to sweeten your Christmas days with our digital CFD Advent calendar. Every day we post a review of our best CFD projects, lifehacks and webinars of the last years, and of course, some new events are also in for you.
So let’s see what’s behind the first door? You think you’ve seen them all? Challenge accepted! Enjoy some insight into the latest projects of Prof. Dr Andreas P. Weiß and his team at the OTH Amberg-Weiden – the so-called “Elektra-Turbine”. Supersonic nozzles, shock waves, unfortunately far too much entropy production – and yet gorgeous! If you like to read more, follow the link.