The history of turbochargers in Formula 1 is pretty fascinating. Turbochargers were initially introduced in 1905, applied to large diesel engines in the 1920’s and found their way into commercial automobiles in 1938. However, it took a few more decades for the turbochargers to be used in Formula 1 car racing.
When Renault decided to enter the sport in 1977, they started their engines based on the novel turbocharger concept. As one would expect, their first design suffered from constant reliability problems through all the races it competed in. As Renault focused their development entirely on the engine, the car’s aerodynamics worsened; it suffered a huge turbolag under acceleration, and when the boost finally triggered the tires were not able to handle it . “So the engine broke and made everyone one laugh”, Jean-Pierre Jabouille, the driver, admitted in an interview. At the time, everyone was looking at the turbo engines as something that no one would ever hear about again.
It is common knowledge that CFD analyses are more of a “see you tomorrow” affair than an “I’ll grab a coffee and I’ll be back”.
Although the fairly recent developments in electronics allow for more computing power while being more affordable, it can still take a significant amount of time to run a good CFD case.
One of the main advantages of running CFD is that there is no need to have an actual, manufactured prototype in order to run an experiment. Prototypes have been known to be mainly restricted to companies/individuals that had manufacturing capabilities and quite a lot of money on their hands. However, with recent advancements like 3D printing, this prototyping is not only possible but is also relatively fast (and getting faster everyday with new techniques being developed).
It comes to a point where it is worth evaluating, qualitatively, each method, however different they actually are.
Although CFD is an extremely common practice in modern day engineering and is immensely useful, it tends to sometimes completely replace actual prototyping and this can create some issues… Indeed, CFD is neither an exact science nor it is always “cheap” (some complex problems can easily cost several thousand dollars in computing costs) but either way it sure has its perks. These two arguments are unfortunately largely part of a general misconception of CFD that decision makers and the younger generation of engineers are often victims of. When managers are given the choice between purchasing a software that can supposedly simulate any physical problem (CFD case) and a machine that can physically build components (manufacturing case) the upfront cost strongly leads these decision makers to adopt the first option.
However, CFD does not always suffice. Results of CFD analyses are influenced by numerical and modeling errors, unknown boundary conditions or geometry and more. Refining your mesh is becoming easier and ultimately leads to reduced numerical errors while, at the same time, increasing your calculation time. Modeling errors can come from misuse or inaccuracy of certain models when trying to simulate real, complex physics like turbulence. And so on to the point that different codes and even different engineers can find some minor discrepancies in the final results of the same case.
This means that less experienced engineers tend to over-trust their results, thinking of CFD as the universal answer to every physical problem. To place (smartly) more confidence in CFD results the codes should be calibrated and corrected based on experimental results that do require prototyping at some point unless a product is wrongly put on the market without proper physical testing – which can happen, unfortunately. Comparing both an original and an optimized geometry in CFD is perfectly possible and realistic but as for any solver a baseline should be created. One cannot simply say he has improved the efficiency of a machine by 2% if the original machine was not analyzed beforehand.
Calibration of the CFD models is based on available data from experiments and this data is often very limited compared to the results that CFD can provide. While a physical test would provide values like power as well as some pressures and temperatures in most cases, CFD analyses can go way beyond this by providing parameters distributions, flow recirculation areas, representation of the boundary layer appearing on the surfaces, etc. that allow getting a good understanding of what is happening to the flow within the machine, which is something that definitely cannot be appreciated in most experimental runs. Beside the mentioned disadvantages that 3D printing has, an important one that is shared with CFD is that the time needed to build a geometry strongly depends on its size. However, CFD can deal with the repetition of an element in a row fairly accurately while the entire wheel has to be manufactured to be analyzed. This sort of restrains rapid prototyping to smaller machines, at the moment.
For these reasons and despite all these “warnings”, CFD remains and will remain an essential engineering tool that provides a good comparison of cases rather than a truly accurate representation of the reality we live in. As a conclusion, CFD still continues to evolve with the recent technological developments and should be supplemented with experimental testing instead of substituting it.
The last few decades have brought with them a dramatic increase in the development and use of turbochargers in automobiles, trains, boats, ships, and aircrafts. There are several reasons for this growth, including rising demand for fuel efficiency, stricter regulations on emissions, and advancements in turbomachinery design. Turbochargers are appearing more and more and are replacing superchargers.
Turbochargers are not the only turbomachinery technology growing in popularity in the marine, automobile, and railroad industries. Organic Rankine Cycles are being applied to take advantage of the exhaust gas energy and boost engine power output. ORCs, a system for Waste Heat Recovery, improve the overall efficiency of the vehicle, train, or boat, and reduce specific emissions.
As the size of the engines we consider increases, there is more heat available to recuperate, and more potential WHR systems to use. For instance, we can consider different combinations of these systems with both non-turbocharged and turbocharged engines. We are able to design and compare engine boost system combinations, with and without a turbocharger, with and without a blowdown turbine, and with and without a WHR system, at the cycle and turbine design levels.
In our upcoming webinar, we will do just that. We will design different combinations for larger ICEs and compare the results. This webinar will also cover introductions to these systems and application examples for supplementary power production systems in the automotive and marine industries.
We hope you can attend! Register by following the link below.
Whether it’s to drive you to work, power up your electronic devices, fly you to your holiday destination (extraterrestrial or not), or even set up the perfect lighting for this Valentine’s Day, your daily life requires power production. Although renewable energies are gaining popularity, many people remain unprepared to make the complete switch to these innovative power sources (except Iceland). Making the things we have more “energy efficient” or “green” has become an attractive marketing tool for many of businesses.
This past Tuesday was the 44th celebrated Earth Day. On Earth Day, more than 100 countries join together to literally stop and smell the roses, appreciate the splendor and beauty of Mother Nature and take extra efforts to be more conscientious for our shared home.
Turbomachinery, though not always the first thing that comes to mind when speaking on the subject of green technology, plays an important role toward our efforts for a more sustainable environment. Continue reading “Sustainable Turbomachinery”→
To have a successful application of an ORC system, the availability of an adequate heat source is crucial. In principal every heat-generating process, such as burning fossil fuel, can be taken as a heat source for ORC.
However, the aim is to improve energy efficiency and sustainability of new or existing applications with the focus on waste heat and renewable energy sources.