scholarly journals Present state and future of high-temperature equipment design. Basic concept of design.

1987 ◽  
Vol 36 (407) ◽  
pp. 903-909
Author(s):  
M. Kitagawa
Keyword(s):  
High Temperature ◽  
Present State ◽  
Basic Concept ◽  
Equipment Design

A Gas Operated Bearing Damper for Turbomachinery

1991 ◽  
Author(s):  
John M. Vance ◽  
Bradley P. Cardon ◽  
Luis A. San Andres ◽  
Albert F. Storace
Keyword(s):  
High Temperature ◽  
Basic Concept ◽  
Critical Speed ◽  
Ball Bearings ◽  
Aircraft Engines ◽  
Power Penalty ◽  
Design Objective ◽  
Phase Lead ◽  
Pressure Phase ◽  
Speed Response

A gas operated bearing damper for turbomachinery has been designed, analyzed, and experimentally investigated in the laboratory. The damper utilizes air bled off from the compressor to power an actuator through orifices with area modulated by the vibratory displacement at the bearing support. The design objective for this passive device is to make the actuating dynamic gas pressure phase lead the vibratory displacement by 90 degrees. Several variations of the basic concept have been tested. An analysis was performed to guide the experiments. All of the designs tested to date can produce positive damping, and one particular design has produced a damping coefficient of 8756 N-s/m (50 lb-sec/in) with a power penalty of 5.2 KW (7 HP) at 310 KPa (45 psi). This design was installed on a laboratory rotor with flexibly supported ball bearings, and significant damping of the critical speed response was demonstrated. The experimental results to date suggest that further research can produce significant improvements in performance, and the device appears to be especially adaptable to high temperature applications for aircraft engines.

The influence of residual and trace elements on hot shortness and high temperature embrittlement

1980 ◽  
Vol 295 (1413) ◽  
pp. 89-103 ◽  
Keyword(s):  
Mechanical Properties ◽  
Trace Elements ◽  
High Temperature ◽  
Present State ◽  
Electric Steelmaking ◽  
Hot Ductility ◽  
High Temperature Mechanical Properties ◽  
Hot Shortness ◽  
Long Time ◽  
Residual Elements

The problems of hot shortness and overheating have beset the metallurgist, forgemaster and smith for a surprisingly long time. In recent years the increase in electric steelmaking has emphasized the difficulties arising from the steady build up of residual elements which is the inexorable consequence of scrap recirculation. Although many of the early investigations considered the influence of individual trace elements on hot ductility, in practice such relatively simple situations seldom arise. More often than not it is the interaction between a combination of trace elements which has to be understood if their net influence on high temperature mechanical properties is to be evaluated. This survey of the present state of knowledge in this field therefore places particular emphasis on the need for an understanding of the interactions between trace elements

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