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形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA1530050000, レポート番号: JAXA-RM-15-010

形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA1530049000, レポート番号: JAXA-RM-15-009

形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA1530040000, レポート番号: JAXA-RM-15-002

A floating ring seal (FRS) has been employed as a noncontact type seal, which seals in high-pressure liquid oxygen for the rocket engine turbopump. The turbopump, high-speed, high-power turbomachinery, has suffered from rotor vibration problems up to the present time. However, as the dynamic behavior of FRS has rarely been focused on, it is necessary to clarify the rotordynamic (RD) fluid forces of FRS. The objectives of the present study were to evaluate the RD fluid forces of FRS analytically (bulk-flow model) and experimentally, and to elucidate the structural behavior of FRS caused by the whirling motion of the rotor. Evaluation of RD fluid forces was attempted, and development of a program for evaluation of the FRS is now in progress. RD fluid forces of FRS were measured by an experimental apparatus with an active magnetic bearing. These forces had no significant impact on rotordynamic stability. The axial force induced by differential pressure presses the floating-ring (FR, the component of the FRS) against the stationary housing. Because of the increasing friction force of the secondary contact surface, high axial loads increase the radial force required to reposition the FR. Therefore, it is very important to investigate rotordynamic forces as tribological behavior., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA0062043000, レポート番号: JAXA-RM-13-008E

A rocket turbopump, high-speed, high-power turbomachinery, has suffered from various rotor vibration problems up to the present time. Establishment of an integrated design method consisting of turbopump components is eagerly expected to suppress the rotor vibration. We are now studying the design method of optimal rotor system by using multidisciplinary optimization due to information-sharing of turbopump components (pump, bearing, seal and turbine). A quality function deployment (QFD) is employed to visualize of the relation between turbopump components., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA0062042000, レポート番号: JAXA-RM-13-007

形態: カラー図版あり, Physical characteristics: Original contains color illustrations, Translation title: CFD analysis of inner fluid flow in a angular contact ball bearing on cryogenic and high speed condition, 資料番号: AA0062039000, レポート番号: JAXA-RM-13-001

形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA0061880000, レポート番号: JAXA-RM-12-009

Because rocket turbopump turbine blades have higher loading, there is a possibility of shaft vibration problem due to "Thomas Force". In order to reduce shaft vibrations, it is important to keep "Thomas Force" small. In the previous report, validity of optimization process for the reduction of Thomas Force was confirmed by performing Parameter Design and Multi-Objective Genetic Algorithm (MOGA). In this paper, by increasing the number of objective functions, the results of multi-objective optimization for reduction of Thomas Force and the considering the feasibility of blade structure are discussed. It was found that optimized blade reduced 10% in weight, 30% in Thomas Force, compared from the original blade., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA0065514000, レポート番号: JAXA-RM-12-007

Due to its special specification, rocket turbopump turbine blades have higher loading and its aspect ratio is extremely low. In such a situation, it is difficult to predict turbine efficiency accurately in system design phase of rocket engine. The purpose of the present work is to evaluate the accuracy of existing one dimensional loss model. By using the steady three dimensional CFD analyses, parametric studies against the major design variables such as tip clearance, blade loading, blade aspcet ratio, were carried out. These simulation results were compared with the results that were also obtained by using the existing one dimensional loss models. The results clarified the cause of the reduction of accuracy of one-dimensional prediction of turbine efficiency. The one-dimensional loss model was found to underestimate the loss under the condition of a blade with a low aspect ratio. From comparison between the existing one-dimensional loss models, it was also found that the "Craig & Cox model" could reproduce the tendency for blade loading correctly., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA0065515000, レポート番号: JAXA-RM-12-008