D. Guichard, F. Laithier, J.-P. Fournier

Snecma has started the development of a new rocket engine for upper stage applications; its name is VINCI. The liquid hydrogen turbopump is two-stage centrifugal including one shrouded impeller per stage and the max peripheral speed is 600 m/s. The cost is the main criterion for the turbopump design. Isoprec®, a new net shape powder metallurgy process developed in a team including Snecma has been chosen for these components production. For turbopump impeller applications the expected benefits of this process are : -) machining simplifications by obtaining Net-Shape surfaces (vanes), -) high dimensional reproducibility, -) good as HIP material properties. Indeed in the frame of a preparatory research and development program, a demonstrator impeller was already manufactured at the same scale ; the feedback in this program allows to directly manufacture the first development VINCI items. The parts are manufactured by Tecphy (HTM group). The main characteristics for VINCI impeller are : Pressure rise per stage: 140 bar; Rotational speed: 100000 rpm; Outer diameter: 110 mm; Tip speed: 600 m/s. In order to check the impeller burst margin Snecma has decided to invest in a spin test facility at cryogenic temperature. This temperature requirement allows testing the impeller in the turbopump temperature conditions and avoiding using similarity rules. The spin test system will be designed for the following requirements: Rotor weight: <50 kg, < 10 kg; Outer diameter: < 250 mm, < 150 mm; Maximum rotation speed: 100000 rpm, 1200000 rpm; Test temperature: from 10 K to Room Temperature. This facility is designed and manufactured by SCHENCK RoTec GmbH (Darmstadt, Germany) on the basis of a standard spin test system by adding a high performance vacuum system and a cooling device using liquid helium and nitrogen. The first burst test of the lsoprec® demonstrator impeller has been performed in October 2000. The burst speed of 145600 rpm at 20 K has demonstrated the potential of the PM process for this application. The spin test will be used in the future to overspeed each flight item instead of performing non destructive controls.

19th European Conference on Materials for Aerospace Applications, Munich, Germany, 2000

Book Chapter

englisch

14,8 x 21,0 cm, 6 Seiten

DGLR-Bericht, 2001, 2001-02, Advanced Aerospace Materials - Proceedings 2000 ; S.265-270; 2001; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

NA

astronautics, rocket engines, pumps

Bibliothek

2001