High Temperature Aged Leakage Relaxation Screening Tests on Confined Flexible Graphite Gaskets

2021 ◽  
Author(s):  
Abdel-Hakim Bouzid ◽  
Shubhra Kanti Das
Keyword(s):  
Weight Loss ◽  
High Temperature ◽  
Degradation Process ◽  
Screening Tests ◽  
Thickness Change ◽  
Graphite Sheet ◽  
Mechanical Feature ◽  
Graphite Oxidation ◽  
Temperature Exposure ◽  
Flexible Graphite

Abstract Flexible graphite-based gaskets are used extensively in high-temperature applications as a replacement of asbestos based gaskets. The effect of aging and temperature exposure of flexible graphite sheet gaskets was the subject of a previous work [1,2], however, the effect when flexible graphite is in a confined gasket configuration is not known. This study outlines the performance evaluation of the elevated temperature behavior of flexible graphite-based gaskets under a confined configuration and exposed over a long period employing HALR (High temperature Aged Leakage Relaxation) fixture. This ARLA-like fixture can retain the mechanical feature of the ATRS/HATR while allowing the cold leakage rate and weight loss measurement. Four different confined gasket configurations, namely corrugated metal, spiral wound, kammprofile and double jacketed, are evaluated within a temperature range of (427 to 649 °C) 800 to 1200 °F and exposure time of 2500 hours. Graphite weight loss, gasket thickness change, leakage and tightness parameter, creep and relaxation measurements were taken at regular intervals for each gasket style. To better understand the aging process, these critical mechanical and leakage properties are scrutinized; the degradation process related to mainly graphite oxidation is further discussed, and a conclusion is drawn.

Investigation on Thermal Stability of Geopolymer Based Zeolite in Fire Case Study

2020 ◽  
Vol 1009 ◽  
pp. 31-36
Author(s):  
Kanokwan Kanyalert ◽  
Prinya Chindaprasirt ◽  
Duangkanok Tanangteerapong
Keyword(s):  
Weight Loss ◽  
Compressive Strength ◽  
High Temperature ◽  
Fly Ash ◽  
Alkali Activation ◽  
Different Types ◽  
Temperature Exposure ◽  
In Fire ◽  
Thermal Stability Of

This work aims to reveal the effects of zeolite on properties of fly ash based geopolymer under high temperature at 300 °C, 600 °C and 900 °C. The specimens were prepared by alkali activation of fly ash, which was partially replaced by two different types of zeolite at 10%, 20% and 30% by weight. The specimens were analyzed for the maximum compressive strength, weight loss percentage, XRD and SEM. The results highlighted that the percentage of weight loss increased with the ratio of zeolite replacement. The compressive strength of geopolymer with synthetic zeolite and natural zeolite at 7, 28, 60 days were similar. The high-temperature exposure resulted in the reduction in compressive strength in all proportions. At the same temperature, compressive strength of all specimens were not significantly different.

Performance of Concrete at Sustained High Temperature in Material Applications

2012 ◽  
Vol 578 ◽  
pp. 150-153
Author(s):  
Hong Zhu Quan
Keyword(s):  
Weight Loss ◽  
Compressive Strength ◽  
High Temperature ◽  
Portland Cement ◽  
Test Results ◽  
Test Procedures ◽  
High Temperature Exposure ◽  
Concrete Properties ◽  
Early Strength ◽  
Temperature Exposure

The effects of sustained high temperature on concrete properties are discussed in this paper. In this experiment, concrete with 6 types of cement were tested after high temperature exposure. Although, test procedures were the same as past literature, test results showed different tendency. The temperature of 50°C at which compressive strength was minimal were found for concrete with high-early strength and medium-heat portland cement, which concrete with other cements showed no change up to 110°C. Relationship between weight loss and compressive strength differed from past literature.

scholarly journals Novel Multilayer SAW Temperature Sensor for Ultra-High Temperature Environments

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 643
Author(s):  
Xuhang Zhou ◽  
Qiulin Tan ◽  
Xiaorui Liang ◽  
Baimao Lin ◽  
Tao Guo ◽  
...  
Keyword(s):  
High Temperature ◽  
Temperature Sensor ◽  
X Ray Diffraction ◽  
Aero Engine ◽  
Before And After ◽  
Application Potential ◽  
Passive Sensors ◽  
Temperature Exposure ◽  
Engine Systems

Performing high-temperature measurements on the rotating parts of aero-engine systems requires wireless passive sensors. Surface acoustic wave (SAW) sensors can measure high temperatures wirelessly, making them ideal for extreme situations where wired sensors are not applicable. This study reports a new SAW temperature sensor based on a langasite (LGS) substrate that can perform measurements in environments with temperatures as high as 1300 °C. The Pt electrode and LGS substrate were protected by an AlN passivation layer deposited via a pulsed laser, thereby improving the crystallization quality of the Pt film, with the function and stability of the SAW device guaranteed at 1100 °C. The linear relationship between the resonant frequency and temperature is verified by various high-temperature radio-frequency (RF) tests. Changes in sample microstructure before and after high-temperature exposure are analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The analysis confirms that the proposed AlN/Pt/Cr thin-film electrode has great application potential in high-temperature SAW sensors.

Creep Properties and Interfacial Microstructure of SiC Whisker Reinforced Si3N4

1989 ◽  
Vol 170 ◽  
Author(s):  
Håkan A. Swan ◽  
Colette O'meara
Keyword(s):  
High Temperature ◽  
Creep Resistance ◽  
Interfacial Microstructure ◽  
Deformation Mechanisms ◽  
Amorphous Films ◽  
Creep Tests ◽  
Creep Properties ◽  
High Temperature Exposure ◽  
Temperature Exposure

AbstractPreliminary creep tests were performed on SiC whisker reinforced and matrix Si3N4 material fabricated by the NPS technique. The material was extensively crystallised in the as received material, leaving only thin amorphous films surrounding the grains. No improvement in the creep resistance could be detected for the whisker reinforced material. The deformation mechanisms were found to be that of cavitation in the form of microcracks, predominantly at the whisker/matrix interfaces, and the formation of larger cracks. Extensive oxidation of the samples, as a result of high temperature exposure to air, was observed for the materials tested at 1375°C.

scholarly journals Beyond the classical kinetic model for chronic graphite oxidation by moisture in high temperature gas-cooled reactors

Carbon ◽  
2018 ◽  
Vol 127 ◽  
pp. 158-169 ◽  
Author(s):  
Cristian I. Contescu ◽  
Robert W. Mee ◽  
Yoonjo (Jo Jo) Lee ◽  
José D. Arregui-Mena ◽  
Nidia C. Gallego ◽  
...  
Keyword(s):  
High Temperature ◽  
Kinetic Model ◽  
Graphite Oxidation ◽  
High Temperature Gas
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