Rocket engines are the perfect creation of the human mind, incorporating our existing knowledge in aerodynamics, thermodynamics, solid and fluid mechanics, and rotor dynamics. Believe it or not, rocket engines designs contain turbopumps that move fuel and the oxidizer into a combustion chamber creating the perfect conditions for their burning and high-efficiency rocket motion. The word “turbopump” means that the pump is driven by the turbine installed on the same shaft or connected to it through a gearbox. This thrilling tandem results in a bunch of rotor dynamics effects inherent in pumps, turbines, high-speed rotors, cryogenic temperature materials, etc. And all these effects must be carefully taken into account during rotor dynamics studies.
A standard schematic of an internally geared turbopump consists of the liquid hydrogen (LH2, fuel) and liquid oxygen (LO2, oxidizer) rotors.
Although the rotor dynamics model is usually simpler than the CAD models, it looks quite complicated in the case of the turbopump. The rotors contain sections that are hollow and sections with some elements inside the hollow space. Read More
There’s nothing quite like rocket science, is there? It’s as fascinating as it is complicated. It’s not enough to just get a design right anymore – you have to get it right on the first go-around or very soon thereafter. Enter AxSTREAM.SPACE and all the functionality upgrades introduced in 2021.
AxSTREAM.SPACE was created by experienced mechanical and turbomachinery engineers to level the playing field when it comes to turbomachine-based liquid rocket engine design. By giving propulsion and system engineers a comprehensive tool that can connect with other proprietary or commercial software packages, the sky is, in fact, not the limit for innovation. It covers everything from flow path aerodynamic and hydrodynamic design to rotor dynamics, secondary flow/thermal network simulation, and system power balance calculations. This year, we are proud to unveil some new features that enhance each of these capabilities, which were developed at the request of our customers.
A critical part of any rocket engine development, as pointed out in a NASA blog, is engine power balance, also known as thermodynamic cycle simulation. AxCYCLE, SoftInWay’s own thermodynamic cycle solver that has been widely used in power generation and aviation is now helping companies build rocket engines from scratch, as well as expand their engine lineup based on an existing system. There are some goodies, however, which make it the perfect tool for power balance, and an asset of AxSTREAM.SPACE.
Corresponding with the development of industrial technology in the middle of the nineteenth century, people dealt with multiphase flows but the decision to describe them in a rigorous mathematical form was first made only 70 years ago. As the years progressed, development of computers and computation technologies led to the revolution in mathematical modeling of mixing and multiphase flows. There are a few periods, which could describe the development of this computation:
«Empirical Period» (1950-1975)
There were a lot of experiments that were done during this period. All models were obtained from experimental or industrial facilities which is why using them was difficult for different cases.
«Awakening Period» (1975-1985)
Because of sophisticated, expensive, and not universal experiments, the researchers’ attention was directed to the physical processes in multiphase flows.
«Modeling Period» (1985-Present)
Today, the models for multi-flow calculation using the equations of continuity together with equations of energy conservation are obtained, which allow describing phase’s interaction for different flow regimes. (A.V. Babenko, L. B. Korelshtein – Hydraulic calculation two-phase gas-liquid course: modern approach // Calculations and modeling journal. – 2016. – TPА 2 (83) 2016. – P.38-42.)
Since the time of industrial development, installation designs have undergone great changes. For example, there are shell and tube evaporators for freeze systems where the heat transfer coefficient has increased 10 times over during the last 50 years. These results are a consequence of different innovation decisions. Developments led to research into mini-channels systems, which is the one of the methods to increase intensification of phase transition. Research has shown that heat exchange systems with micro and nano dimensions have a much greater effect than the macrosystems with channels dimensions ≤3-200 mm.
In order to organize fundamental research, it is very important to understand hydro, gas dynamics, and heat changes in two-phase systems with the phase transition. At present, the number of researchers using advanced CFD programs has increased. Our team is one of the lead developers of these program complexes. Mathematical modeling of compressible multiphase fluid flows is interesting with a lot of scientific directions and has big potential for practical use in many different engineering fields. Today it is no secret that environmental issues are some of the most commonly discussed questions in the world. People are trying to reduce the emissions of combustion products. One of the methods to decrease emissions is the organization of an environmentally acceptable process of fuel-burning with reduced yields of nitrogen and sulfur. The last blog (https://blog.softinway.com/en/modern-approach-to-liquid-rocket-engine-development-for-microsatellite-launchers/) discussed numerical methods, which can calculate these tasks with minimal time and cost in CFD applications.
For more effective use of energy resources and low-potential heat utilization, the choice of the Organic Rankine Cycle (ORC) is justified. Due to the fact that heat is used and converted to mechanical work, it is important to use a fluid with a boiling temperature lower than the boiling temperature of water at atmospheric pressure (with working flow-boiling temperature about 100⁰C). The usage of freons and hydrocarbons in these systems makes a solution impossible without taking into account the changes of working fluid phases. Read More
Quite surprisingly, rockets in their primal form were invented before turbomachinery, even though turbines and pumps are both present in modern launcher engines. However, it is interesting to note that both can be traced to the same ancestor. In this post we will discuss some of the history and technical evolution of rockets and turbomachinery – and this all starts with an old pigeon.
Circa 400BCE, a Greek philosopher and mathematician named Archytas designed a pigeon-like shape made out of wood that was suspended with wires and propelled along these guides using steam demonstrating the action-reaction principle long before Newton formalized it as a rule in Physics. As we know today, the faster and the more steam escapes the pigeon, the faster it goes. Turn this 90 degrees to have the bird face upward, and you have a very basic rocket concept. However, rockets are a lot more complex than this, and do not typically use steam (except in the case of liquid hydrogen + liquid oxygen propellants) as the propelling fluid. Read More
Rockets have always fascinated us and to this day a rocket launch is still a global news event worth watching. The sheer noise, power and sight after you hear that “…3-2-1, Lift off!” leave us in awe. A masterpiece of engineering, the recent historic manned SpaceX Falcon 9 launch was no exception. Or was it?
From the outside, a rocket does not look especially advanced – a mere ‘stick’ with a big flame shooting out at one end. The principal concept is simple, too, but the inner workings of a modern liquid-fuel rocket are highly complex.
The first rockets are believed to have existed in China, around 1200. The invention of gunpowder was crucial to the development of these primitive rockets, which were fireworks initially and then weapons. Multistage so-called ‘fire arrows’ were documented during the early Ming Dynasty (Figure 1). The designs were based on bamboo sticks – still a little way off a Falcon 9.
With the rise of gunpowder, this crude rocket technology spread throughout the Middle East and Europe.
The next rocketry milestone came in the 1780s, when the Indian military developed Mysorean rockets with iron castings and successfully deployed them against the British East India Company. Read More
Mechanical engineering is an ever-changing field, and we want to be there to help engineers stay ahead of the curve, even while they are flattening it. In that spirit, we wanted to share with you our different training options that are available now. Whether you are looking to brush up on the fundamentals, or evaluate a software platform, this is a great time to train and explore the latest and greatest in turbomachinery engineering.
Without further ado, let’s get into it!
Private Corporate Trainings Online
First and foremost, the best most comprehensive training you can get from SoftInWay is a private session with one of SoftInWay’s lead engineers and your team. Why is this the best training option? A couple of reasons:
Courses are entirely customizable: The scope of these private training courses is tailored to your specific needs. Are you looking to learn the fundamentals? Or perhaps you want to expand your team’s R&D capabilities when it comes to turbomachinery, rotor dynamics, and 1D thermal systems? Whatever the application, we’ll work with you to develop a course curriculum which brings the most value to you and your team.
One-on-one consultation with our expert engineers on individual projects and challenges. Our engineering expertise ranges from flowpath design on a turbomachine, to rotor dynamics, as well as secondary flows/multiphase flows, and other all-encompassing projects such as liquid rocket engine design.
ll registrants get a 1-month license of the relevant AxSTREAM modules. During the class, users will be familiarized with the ins and outs of AxSTREAM, and be able to make use of AxSTREAM’s capabilities for 1 month afterwards.
The class can be as long or as short as you need and scheduled around you and your team. Read More
Microsatellites have been carried to space as secondary payloads aboard larger launchers for many years. However, this secondary payload method does not offer the specificity required for modern day demands of increasingly sophisticated small satellites which have unique orbital and launch-time requirements. Furthermore, to remain competitive the launch cost must be as low as $7000/kg. The question of paramount importance today is how to design both the liquid rocket engine turbopump and the entire engine to reduce the duration and cost of development.
The system design approach applied to rocket engine design is one of the potential ways for development duration reduction. The development of the design system which reduces the duration of development along with performance optimization is described herein.
The engineering system for preliminary engine design needs to integrate a variety of tools for design/simulation of each specific component or subsystem of the turbopump including thermodynamic simulation of the engine in a single iterative process.
The process flowchart, developed by SoftInWay, Inc., integrates all design and analysis processes and is presented in the picture below.
The preliminary layout of the turbopump was automatically generated in CAD tool (Block 11). The developed sketch was utilized in the algorithm for mass/inertia parameters determination, secondary flow system dimensions generations, and for the visualization of the turbopump configuration. The layout was automatically refined at every iteration. Read More
Operation of most liquid-propellant rocket engines, first introduced by Robert Goddard in 1926- is simple. Initially, a fuel and an oxidizer are pumped into a combustion chamber, where they burn to create hot gases of high pressure and high speed. Next, the gases are further accelerated through a nozzle before leaving the engine. Nowadays, liquid propellant propulsion systems still form the back-bone of the majority of space rockets allowing humanity to expand its presence into space. However, one of the big problems in a liquid-propellant rocket engine is cooling the combustion chamber and nozzle, so the cryogenic liquids are first circulated around the super-heated parts to bring the temperature down.
The Internet practically exploded early yesterday morning with talk of an extraterrestrial discovery after a signal was detected by a Russian telescope. The star in question, HD 164595 located a vast 95 light years away, sent out a strong radio spike that was picked up and sparked a boom of excitement. According to an article published by National Geographic, however, this signal may not be what it was first interpreted as.
Astronomers have pointed their radio telescopes towards the stars for over half a century, hoping to catch a glimmer of life beyond this planet. Short of a futuristic rocket ship, these telescopes seem to be the best bet for catching a peak of something out of this world. That is a main cause as to why this discovery is so tantalizing to both scientists and the rest of us earthlings. However, after further investigation, neither the Allen Telescope Array, commanded by the SETI (the Search for Extra-Terrestrial Intelligence) Institute, nor the Green Bank Telescope, used by the Breakthrough Listen project, turned up additional signals or observations.
Another issue that has risen according to this article is that the signal did not repeat and could have been caused by something else. A source on Earth, such as a faulty power supply, military transmission, or arcing electrical fence for example. Another possible explanation could be that gravity from another object in space amplified a weaker signal. That being said, it would appear that HD 164595 is similar in many ways to our sun. It is composed of the same ingredients, is approximately the same age and has at least one planet in its orbit. This would suggest that theoretically, it would be plausible for life to exist within this system.
Liquid 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.
Turbo-pump design affect payload in different ways:
Inlet suction pressure. As suction pressure goes up, the tank and pressurization system weight increased and reduce the payload.
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!