High Speed Characterization of a Prototype Leaf Seal on an Advanced Seal Test Facility

Author(s):  
Michael J. Pekris ◽  
Adele Nasti ◽  
Ingo H. J. Jahn ◽  
Gervas Franceschini

Advanced contacting seals, such as leaf seals or brush seals, can offer reduced leakage during engine operation when compared to conventional labyrinth seals. The flexible elements of these seals provide better compliance with the rotor during flight manoeuvres. The functionality and performance retention attributes of an engine-scale prototype leaf seal have been investigated on a seal test facility at Rolls-Royce that achieves engine-representative pressures and speeds and allows dynamic control of the seal position relative to the rotor, both concentric and eccentric. In this paper the experimental setup and the test method are described in detail, including the quantification of the measurement uncertainty developed to ASME standard PTC 19.1. Experimental data are presented that show the variations in leakage and torque over typical variations of the test parameters. Insight is gained into the interactions between the operating pressure and speed and the concentric and eccentric movements imposed on the seal.

Author(s):  
Michael J. Pekris ◽  
Adele Nasti ◽  
Ingo H. J. Jahn ◽  
Gervas Franceschini

Advanced contacting seals, such as leaf seals or brush seals, can offer reduced leakage during engine operation when compared to conventional labyrinth seals. The flexible elements of these seals provide better compliance with the rotor during flight maneuvers. The functionality and performance retention attributes of an engine-scale prototype leaf seal have been investigated on a seal test facility at Rolls-Royce that achieves engine-representative pressures and speeds and allows dynamic control of the seal position relative to the rotor, both concentric and eccentric. In this paper, the experimental setup and the test method are described in detail, including the quantification of the measurement uncertainty developed to ASME standard PTC 19.1. Experimental data are presented that show the variations in leakage and torque over typical variations of the test parameters. Insight is gained into the interactions between the operating pressure and speed and the concentric and eccentric movements imposed on the seal.


Author(s):  
Alberto Serena ◽  
Lars E. Bakken

Part load operation of pumps generates flow and machine instabilities, which are not desirable and should be avoided as they result in premature wear and mechanical problems. Two-phase flow introduces additional challenges, both at the design and operational stages, due to the different phase behavior and mutual interaction. The phenomena involved present an intermittent character and are strongly dependent on the specific geometry and operating conditions. Despite the recent promising development of numerical simulations capabilities, an accurate characterization of the flow mechanisms still relies on real tests, which are needed to validate the numerical models too. An advanced laboratory test facility built at the Norwegian University of Science and Technology provides the required optical access to the pump channels, and high-speed recordings, along with local measurements of the pressure pulsations, allow to describe the flow structures in terms of location, length and time scales, and relate them to overall machine measurements, such as flow, pressure and torque. This provides a wide collection of test data of great value for a further understanding of the surging phenomenon, the development of a surging onset prediction model and a control strategy. Tests are performed covering the whole range of flow rates; a characteristic surging condition is identified and described in the article.


2006 ◽  
Vol 129 (2) ◽  
pp. 136-145 ◽  
Author(s):  
Xiongjun Wu ◽  
Georges L. Chahine

A high speed/high flow test facility was designed and implemented to study experimentally the supercavitating flow behind a projectile nose in a controlled laboratory setting. The simulated projectile nose was held in position in the flow and the cavity interior was made visible by having the walls of the visualization facility “cut through” the supercavity. Direct visualization of the cavity interior and measurements of the properties of the cavity contents were made. Transducers were positioned in the test section within the supercavitation volume to enable measurement of the sound speed and attenuation as a function of the flow and geometry parameters. These characterized indirectly the content of the cavity. Photography, high speed videos, and acoustic measurements were used to investigate the contents of the cavity. A side sampling cell was also used to sample in real time the contents of the cavity and measure the properties. Calibration tests conducted in parallel in a vapor cell enabled confirmation that, in absence of air injection, the properties of the supercavity medium match those of a mixture of water vapor and water droplets. Such a mixture has a very high sound speed with strong sound attenuation. Injection of air was also found to significantly decrease sound speed and to increase transmission.


Author(s):  
Rocky Shih ◽  
Cullen E. Bash

The principle of measuring thermal resistance of thermal interface material (TIM) by sandwiching the material between a hot block and cold block is well known in the industry. TIM manufacturers usually use a variation of the industrial standard ASTM D5470 test method, and subsequently provide data that is difficult for the end user to effectively utilize for product development. This paper will discuss the design and construction of an automated TIM test system based on the ASTM D5470 standard. This automated test vehicle provides an independent study of various TIMs. The instrument enables standardized testing and performance documentation of interface materials from a wide array of manufacturers making it easier for end-users to compare and select the appropriate material for various applications. The automated test method is faster and easier to use than previous methods. It requires minimal operator intervention during the test and can perform preconditioning, and non-uniform heating if required. Experimental results obtained from the instrument will be discussed.


Author(s):  
Angelo Pasini ◽  
Riccardo Simi ◽  
Gabriele Brotini ◽  
Alessandro Apollonio ◽  
Luca d'Agostino ◽  
...  
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