International space industry as well as European space industry continues to develop in areas such as space exploration, Earth observation, science and telecommunications. In order to ensure this development, transportation systems are required (rockets) that are themselves propelled by high performance engines.
The current tendency is minimizing the volume that the propellants occupy inside the tanks in order to ensure a higher power-to-weight ratio of the rocket and a bigger load. Liquid systems enable higher specific impulse than solids and hybrid rocket engines, can provide very high tankage efficiency and present throttle, shut down and restart capabilities.
The performance of liquid propelled rocket engines presents a crucial dependency towards the turbopump assemblies. Current liquid propelled rocket engines development time and maintenance costs to a large extent are determined by the performance of and the technologies used in turbopumps assemblies.
The level of sophistication and reliability of the turbopumps assemblies has a significant impact on engine performance.
The turbopump system represents the highest loaded engine component with a large number of interrelated design elements. Complex design, high rotation speeds, and a direct link between turbopump system operating conditions and the processes occurring in the engine are the reason that defects attributable to the turbopump assembly represent a large proportion of the overall engine defects during development. Difficulties in eliminating defects occurring in the course of engine development are caused by the fact that processes occurring in a turbopump are by nature transient.
Trend technology to develop through present project is based on advanced principles and methods to optimize the entire development cycle involved in designing and manufacturing this complex and vital rocket engine subassembly. The research results of the project can be extrapolated and used to increase the efficiency and reduce cost by utilizing a solid structured data base for material and technology suppliers, upgrading existing software capabilities to suit requirements, increase efficiency in the manufacturing sector.
Cosmic Vision 2015 – 2025 is the current cycle of ESA’s long-term planning for space science missions. That means ten to twenty years from now, a succession of clever new spacecraft will need to fly according to ESA’s continuing Science Programme, called Cosmic Vision.
The new spacecraft requires a new-generation of liquid propulsion systems for launch vehicles.
The present project prepares the way to produce a new turbopump for Europe’s Ariane launcher and opens the collaboration with SNECMA FRANCE, the lead engine supplier on Ariane launcher and the world’s second largest manufacturer of liquid propulsion systems for launch vehicles.
This collaboration is in line with the Plan for European Cooperating States (PECS) designed to help European countries, particularly those that joined the EU after 2004 as it is the situation of Romania.
At present Romania has signed a PECS Charter. PECS is helping to stimulate relations with interested countries, to expand the overall European scientific and industrial base and to enrich ESA as a research and development organisation.
A similar solution hasn’t been previously studied in Romania and an optimal solution is necessary to be found in order to align national competencies and achievements in the international ones. Given previous achievements on high-speed equipment, COMOTI Institute has the necessary competence to develop a solution that is compatible to the international ones.
In this project, DevPump, a practical harmonization with international technologies and methodologies - aspect that is in accordance with the ESA strategy. Thus, for the project, in accordance with ESAs Technology programmes, a critical evaluation of international existing solutions will be realized in order to introduce an improved centrifugal flow module that can be widely used.
Through this preliminary study decrease the risks generated by non-European equipment manufacturer’s dependence, essential part of the European Component Initiative of ESA. By realizing all the necessary activities in the European area, the European space programs and implicitly ROSA’s will evolve significantly compared with similar associations outside EU borders.
In conclusion, the general objectives of the project consist in:
Development and promoting the national research capacities in the field of turbopumps for liquid rocket engines;
Multidisciplinary training of specialists at the highest level in hydro-gasodynamics, structural analysis, cryogenics, the study of materials and innovating technologies.
To respond to these requests, the project proposal pursues the development of an advanced mechanism of strategic planning to design and manufacture a high-precision, high-reliable turbopump system for liquid propellant rocket engines.
The list of specific objectives for DevPump result from the main technical and scientific issues and is as follows:
1.strategic planning in order to develop the main components of the turbopump system (pump, turbine, shaft, bearings, seals);
Within the framework of this objective main turbopump components development planning is considered: the pump and the turbine. The working plans dedicated for manufacturing these two key components present a great level of complexity since they represent unique rotating machineries that work with cryogenic liquids and hot high pressure gasses respectively.
The working plans for the two main components present mostly the same phases:
-documentation study regarding turbopumps fluid dynamics and mechanical features in order to determine general demands and special demands from the material point of view ;
-identification of potential material and technology suppliers in order to establish a solid data base;
-testing the existing software dedicated to hydro-gasodynamics calculus with gaseous and liquid types of fluid (particularly hydrogen and oxygen) and also validating the results with reference cases (computer tools like Computer Aided Design, Computational Fluid Dynamics and Finite Element Analysis will be employed to give accurate and extensive results); a 3D CAD model of the turbine will be created and numerical simulations will be computed to see how the working conditions affect the material behaviour; rotational speed, temperature, mass flow and pressure will be the input data for the CFD environment the most important output being the temperature and pressure distribution on the turbine blades;
-testing the existing software dedicated to mechanical resistance calculus(FEA);
-manufacturing technologies for the two key components of the turbopump system from the identification point of view of the machines and tools involved in the manufacturing process, and also from an operation planning perspective.
2.strategic planning in order to develop the entire turbopump assembly and the technology;
This objective consists in a single phase in which a report will be compiled, report that describes a working plan which successfully identifies all the activities required in the manufacturing process for all other components of the turbopump assembly. The working plan also integrates the assembly process as well as hydro-gasodynamics calculus and resistance calculus performed in the entire turbopump system.
Two additional stages are integrated besides the ones mentioned above:
-study regarding seals;
-mechanical balancing study of rotor systems in order to determine the technological constraints imposed when building such turbopump system; although balancing is well known and even standardized for rotary parts, when speaking about high speed components the problem may be difficult and will be studied with respect to material manufacturing processes.
3.strategic planning in order to develop a test bench facility dedicated for turbopump testing;
The completion of this objective will result into a working plan consisting in the following stages:
-documentation regarding current state of test bench facilities dedicated for turbopumps
-once the parts obtained they will be checked using 3D measuring machines allowing to verify the actual obtained geometry with the CAD model of the part
-testing programs development in order to define parameters that need to be measured during the turbopump testing
-test bench setup dedicated for testing turbopumps along with equipment required for testing (low density liquids used lead to special storing installations)
-instrumentation methodology defining – identification of instrumentation systems for eventual purchase
-conducting tests in order to determine turbopump performance
However, the original approach in DevPump consists in the evaluation of state-of-the-art tools in each and every part of the resulting development plan. These tools, both virtual (computer) and real (machining) tools are already in use for different applications but a strategic plan capable to give optimum results has been never conceived from early or even pre-design phases.
Novelty is present at almost every level since latest developments will be exploited in such manner to ensure that a turbopump constructed following the resulting plan will overcome the disadvantages of already existing products in terms of technical and economical efficiency.
The project is in itself innovative by the nature of the involved partners which come from the aeronautical field and from the cryogenic sector, creating a partnership with unprecedented potential in the field of rocket technology in Romania and even Europe.