Category: Analysis

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Turbo pump design parameters for Liquid Propulsion

Posted by Ursula Shannon

turbo3aLiquid propellant rocket is known as the most common traditional rocket design. Although the first design was launched back in 1926, liquid propellant rocket remains a popular technology which space exploration companies and institutions study for further improvement.

The implementation of this particular technology is based on a simple idea: fuel and oxidizer are fed through a combustion chamber where both liquids will met and burned to produce launching energy. In order to inject propellant to combustion chamber, a turbo-pump is used to create required pressure . The turbo-pump design and operating parameters contribute to the optimization of both turbo-pump and engine system performance. The pump needs to be designed to avoid cavitation while operates pushing the liquid to combustion chamber.

There are three different cycles which are often used in liquid propellant rocket: the staged combustion, expander and gas generator cycle. Configuration of the turbo-pump strongly relies on the cycle and engine requirements –thus the best design must be selected from options available for the particular cycle’s optimal parameters. For example for staged combustion cycle, where turbine flows is in series with thrust chamber, the application allows high power turbo-pumps; which means high expansion ratio nozzles can be used at low altitude for better performance. Whereas, for implementation of gas-generator cycle, turbine flows are linked in parallel to thrust chamber, consequently, gas generator cycle turbine does not have to work the injection process from exhaust to combustion chamber, thus simplified the design and allows lighter weight to be implemented.

Some parameters are interdependent when it comes to designing a turbo-pump, i.e: turbo-pump cycle efficiency, pump specific needs, pump efficiencies, NPSH, overall performance, etc. Often in practice, pump characteristics will determine the maximum shaft speed at which a unit can operate. Once it’s determined turbine type, arrangements, and else can be selected. Another thing that must be taken into consideration while designing a turbo-pump is how it affect the overall payloads.

Schematic of a pump-fed liquid rocket
Schematic of a pump-fed liquid rocket

Turbo-pump design affect payload in different ways:

  1. Component weight
  2. Inlet suction pressure. As suction pressure goes up, the tank and pressurization system weight increased and reduce the payload.
  3. Gas flowrate, since increase in flowrate decrease the allowable-stage burnout weight, which would decrease payload weight.

All those has to be taken into consideration while trying to select an optimal design of turbo-pump, since it crucially affects overall performance of the engine.

Want to learn more how to design a turbo-pump? Check out AxSTREAM as your design, analysis and optimization tool!

 

References:
Turbopumps for Liquid Rocket Engines
Design of Liquid-Propellant Rocket Engines
Principal of Operation – Liquid-propellant rocket
Staged combustion cycle
Gas-generator cycle

Re-inventing the wheel (or perhaps our education system)?

Posted by Valentine Moroz

I hope everyone is having a great week. I wanted to write about our education system, as it relates to Turbomachinery, and perhaps some challenges that educators / students face, and some ideas for how things can be improved.

As computation technologies have evolved over the last 30-40 years, it seems that a large number of education institutions are still behind.

Part of my job at SoftInWay, is to make sure that local  & global Universities involved in Turbomachinery have the most advanced software tools, so that the students graduating from undergraduate, as well as Masters and PhD level programs, have some kind of relevant skills to develop / optimize Turbomachinery, as well as know how to use relevant software tools.

From talking to Academia from different countries, it seems that professors (perhaps due to bureaucracy of their positions) are often faced with several challenges / decisions:

1. No budget for software tools thus forced to use free tools

2. Desire to create their own software, to eventually spin off and start a company

3. Lack of deep technical program, thus only picking macro topics as they relate to turbomachinery as general thermodynamics, etc. (which is important also).

What’s the problem with all of these approaches: When students graduate, and want to go into the field of Turbomachinery, a large portion of these students think that “Turbomachinery Design” can be done with CFD.

Looking at the last 5-10 years of CFD as it relates to Turbomachinery, people have been in several “camps”, with the most known names (such as products from Ansys, or CD Adapco (now owned by Siemens), Numeca, and some free open source CFD codes.  Additionally, there has been a plethora of free or academic codes written by 100s of wide-eyed graduates students in hoping of making the next big software company.

Why does this cripple the education system, industry and the general concept of innovation? First of all, in all of these packages, you are going on the assumption that you already have a geometry of the turbomachinery and generally know what the machine looks like. Granted, some advertise that by “partnering” with other vendors they can do 1D or inverse design, when looking at these options closely, they are still very weak.   At the same time, there are lessor known CFD packages (from example our Turbomachinery specific CFD module AxCFD that we offer) that while hasn’t been aggressively marketed, comes at 30% of the cost, and has not only faster computation speed, but is fully integrated in a complete turbomachinery design platform. While this is a great option for students, very few know about it, and we are always stuck with a thought “people need to understand the complete process of design, not just CFD, so let’s focus on teaching that, and sharing that message”.

In addition to working with Universities, another part of my job at SoftInWay is hiring, so what have i learned from looking at 1000s of resumes from masters and PhD students?

If you start to dig deeply, about what candidates have learned about turbomachinery design, how well do they understand, for example, compressor aerodynamics, or gas turbine cooling, quite often the answers come up short. This creates a steep learning curve, not just for our company, but also for major manufacturers and service providers.

We believe, that instead of the next generation of students, trying to re-invent the wheel, and spend their 2,3,4,5,6 years of education  on equations and writing code, for a problem that has been solved, they should use a holistic approach, to advance, Power Generation, Transportation, Propulsion and Advance the clean energy space.

We have created a range of free resources for students in an online university format (learn.softinway.com) and encourage everyone to dig deeply, and together we can create a greener world, for the future generations.

Additionally, our turbomachinery development platform AxSTREAM (r), is the only platform in the world which is wholly integrated and developed in-house, including thermodynamic cycle design, 1D,2D,3D turbomachinery design, analysis and optimization, rotor dynamics and bearing design, stress analysis, advanced optimization and visualization, etc.

** Feel free to fact check this by looking at your current software simulation tools, and see how many modules or features or “tools” are borrowed from other companies.  How can one ever learn and understand how things work and talk to each other, if knowledge is not developed, but rather borrowed.

If  you are a student, or a professor at a college or university, and are interested in improving your turbomachinery program, and giving your students the extra skills (fundamentals and software), to really develop innovations, please write me a message !

Message Me

What parallels exist between traditional Gas Turbines with SCO2 turbine of the future?

Posted by Maksym Burlaka

At the beginning of my studying of the peculiarities of supercritical CO2 (S-CO2) cycle I was wondering: why do scientists involved in this area state that highest temperature limit for the cycle is about 650-700 ˚C. In turn, the inlet temperature in the first stages of gas turbines handles the temperatures about 900 ˚C without cooling at similar pressure levels as for supercritical CO2 Turbines. As a result the following question rose in my mind – why the temperature magnitudes of 900 ˚C are not achievable in S-CO2 turbines?

As a next step, some investigations were performed with the aim to reveal the essence of such a temperature limit. Eventually the result was quite obvious but rather interesting. The density of S-CO2 is significantly higher than the density of combustion products at the same pressure and temperature magnitudes. This fact means that stresses at static vanes and rotating blades are significantly higher than in gas turbines vanes and blades at the same conditions. Therefore the maximum allowable temperature for S-CO2 turbine will be respectively less with the same high temperature material. However, you might say that there is another way to solve the problem with stresses, namely, increasing the chords of blades, leading edge thickness, trailing edge thickness, fillets etc. This approach would lead to such blades shape and turbine cascade configuration that their aerodynamic quality becomes very low so the gain in efficiency at cycle level will be leveled.

Interested in learning more about our research, and how using the AxSTREAM turbomachinery platform, we were able to study these phenomena?

Contact us for a chat!

Crowd Sourcing Innovation – What’s your vision?

Posted by Valentine Moroz

Dear Friends,

I hope that you are having a great week. In case that you are not on our mailing list, I wanted to share some updates and discuss innovation.

Typically, every week we send marketing or information emails about our latest customers, case studies, upcoming webinars & seminars, etc.

However, after along product development meeting planning our next 3-9 month, I wanted to reach out to the world and ask: how can we help? What don’t you like about your current engineering process? How can you do what you do faster? What would it take to develop a truly more efficeint machine?

Simulation technology and computers have come a long way in the last 30+ years, and yet there are still many companies, and engineering departments stuck using old designs, and methods.

For those of you who have attended the 2005 Turbo Expo in Montreal, we first publically laid out the idea of “Collaborative Development” and “Crowd Sourcing Innovation”: Watch Video

We are working hard on getting ready the next generation of AxSTREAM Platform, and AxCYCLE, with features and level of integration, that the industry has never seen before.

If you have a few minutes, we would appreciate you answering a few questions, and providing some ideas / or some pains / frustrations you may currently have about your turbomachinery design/analysis process.
**** 10 people will be picked at random, to receive a free access to our online, self-paced, Turbomachinery Course of their choosing.

Please respond by filling out this questionnaire: Questionnaire

We greatly appreciate your help, and feedback.
Warmest Regards,
Valentine Moroz

Turbochargers in Formula 1

Posted by Seyed Ghoreyshi

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 [1]. “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.

MMR, twin turbocharged GT500 V8 engine, from Mustangs Daily [3].
MMR, twin turbocharged GT500 V8 engine, from Mustangs Daily [3].
From theJUDGE13 [2].
From theJUDGE13 [2].
 

 

 

 

 

 

Continue reading “Turbochargers in Formula 1” →

Is CFD Evolving Fast Enough for the Technologic World?

Posted by Clement Joly

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.

AxCFD
The AxCFD module in SoftInWay’s AxSTREAM

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.

Innovative Boost of Larger Internal Combustion Engines

Posted by Sarah Decelle

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.

turbocharger
Turbocharger

 

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.

[su_button url=”http://www2.softinway.com/automotivewebinar” target=”blank” radius=”round” icon=”icon: arrow-right”]Register[/su_button]

 

Power Production Does Not Have To Be So Wasteful

Posted by Clement Joly

Update – March 1, 2023: AxCYCLE is our legacy software depreciated by AxSTREAM System Simulation. System Simulation was born out of the union of the legacy AxCYCLE and AxSTREAM NET software packages.

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.

Presentation of the boundary conditions, unrecuperated and recuperated waste heat recovery cycles in AxCYCLE™
Presentation of the boundary conditions, unrecuperated and recuperated waste heat recovery cycles in AxCYCLE™

Continue reading “Power Production Does Not Have To Be So Wasteful” →

Sustainable Turbomachinery

Posted by Valentine Moroz

iStock_000015544357MediumThis 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” →

SoftInWay April Events and Why You Should Attend

Posted by Jackie Bowser

Update – March 1, 2023: AxCYCLE is our legacy software depreciated by AxSTREAM System Simulation. System Simulation was born out of the union of the legacy AxCYCLE and AxSTREAM NET software packages.

supercriticalco2inaxcycleMarch just really flew by!

We’re kicking off April with our new Heat Balance Calculation with AxCYCLE online classes this month. Here’s three good reasons you should attend:

1. You’ll get to learn, understand and dive into our new conceptual cycle analysis tool that has built-in customizable OEM turbine and ICE libraries (perfect for engineers involved in waste heat recovery) Continue reading “SoftInWay April Events and Why You Should Attend” →