A High-Temperature Assessment of Air-Cooled Unsteady Pressure Transducers

1998 ◽  
Vol 120 (3) ◽  
pp. 608-612 ◽  
Author(s):  
D. G. Ferguson ◽  
P. C. Ivey
Keyword(s):  
High Temperature ◽  
Control Systems ◽  
Thermal Protection ◽  
Transfer Model ◽  
Test Bed ◽  
Cooling Effectiveness ◽  
Pressure Transducers ◽  
Unsteady Pressure ◽  
Cooling Medium ◽  
Source Flow

This paper discusses the problem of measuring unsteady pressure in a high-temperature environment using standard transducers. Commercially available cooling adapters for these transducers use water as the cooling medium to provide thermal protection. This arrangement is suitable only for some test bed applications and not suitable for integration into in-flight active control systems. An assessment of the cooling effectiveness of a commercial water-cooled adapter using air as the cooling medium is presented using an experimentally validated finite element heat transfer model. The assessment indicates survival of an air-cooled transducer, itself rated to 235°C, at source flow temperatures up to 800°C.

scholarly journals A High Temperature Assessment of Air-Cooled Unsteady Pressure Transducers

1997 ◽  
Author(s):  
Derek G. Ferguson ◽  
Paul C. Ivey
Keyword(s):  
High Temperature ◽  
Control Systems ◽  
Thermal Protection ◽  
Transfer Model ◽  
Test Bed ◽  
Cooling Effectiveness ◽  
Pressure Transducers ◽  
Unsteady Pressure ◽  
Cooling Medium ◽  
Source Flow

This paper discusses the problem of measuring unsteady pressure in a high temperature environment using standard transducers. Commercially available cooling adapters for these transducers use water as the cooling medium to provide thermal protection. This arrangement is suitable only for some test bed applications and not suitable for integration into inflight active control systems. An assessment of the cooling effectiveness of a commercial water cooled adapter using air as the cooling medium is presented using an experimentally validated finite element heat transfer model. The assessment indicates survival of an air-cooled transducer, itself rated to 235°C, at source flow temperatures up to 800°C.

scholarly journals Unsteady Pressure Measurement in a High Temperature Environment Using Water Cooled Fast Response Pressure Transducers

1995 ◽  
Author(s):  
D. G. Ferguson ◽  
P. C. Ivey
Keyword(s):  
High Temperature ◽  
Elevated Temperatures ◽  
Thermal Protection ◽  
Dynamic Pressure ◽  
Fast Response ◽  
Ambient Conditions ◽  
Pressure Transducers ◽  
Unsteady Pressure ◽  
Temperature Environment ◽  
High Temperature Environment

Measurement of unsteady pressure is a requirement in many proposed aero-engine active control systems. In the high temperature environment associated with the engine, thermally unprotected transducers may not measure accurately or even survive. This paper reports an examination of two water cooled, commercially available unsteady pressure transducers, which assesses the ability of the transducer to accurately measure unsteady pressure when mounted in a water cooling adapter and the effectiveness of the thermal protection at high temperatures. Mounting the transducer in a cooling adapter was shown to have no adverse effect upon its ability to measure dynamic pressure. Deliberately recessing the adapter back from the flow provided the most stable and predictable output at all flow conditions tested. Thermal protection allowed the transducer to survive at flow temperatures of up to 500°C with a potential to survive at higher temperatures. No reduction in performance is shown at elevated temperatures relative to performance at ambient conditions.

An Air-Cooled Jacket Designed to Protect Unsteady Pressure Transducers at Elevated Temperatures in Gas Turbine Engines

2002 ◽  
Author(s):  
Paul C. Ivey ◽  
Derek G. Ferguson
Keyword(s):  
Gas Turbine ◽  
Pressure Transducer ◽  
Elevated Temperatures ◽  
Thermal Protection ◽  
Pressure Sensors ◽  
Air Cooling ◽  
Pressure Transducers ◽  
Unsteady Pressure ◽  
Cooling Media ◽  
Aero Engines

Current unsteady pressure sensors have a limiting upper temperature range and with few exceptions cannot survive at the temperatures experienced in gas turbine aero-engines. This paper describes a design and development study of an air-cooled commercially available unsteady pressure transducer capable of operation at temperatures exceeding 900 °C. The research objective for this work is the following: To design a cooling adapter, using air as the cooling media, capable of protecting a standard unsteady pressure transducer, whose maximum operating temperature is around 250 °C. in a gas turbine engine environment where temperatures typically reach 800–l500 °C. In addition the provision of thermal protection must not adversely effect the measurement of unsteady pressure and the cooling adapter and transducer assembly must be small enough to access critical parts of the engine. Current transducer can operate at temperatures exceeding 250 °C; the purpose of this paper is to demonstrate the additional protection offered by air-cooling. The paper describes the validation experiments conducted for this design, the level of thermal protection achieved and the frequency response of the transducer/cooling jacket assembly.

Amplified Pressure Transducers Using SOI Sensors and SOI Electronics, Suitable for High Temperature Operation (250°C)

2011 ◽  
Author(s):  
Alex A. Ned ◽  
Wolf S. Landmann ◽  
Andrew Bemis ◽  
David S. Kerr
Keyword(s):  
High Temperature ◽  
Control Systems ◽  
Distributed Control ◽  
Integrated Circuit ◽  
Pressure Sensors ◽  
Silicon On Insulator ◽  
Centralized Control ◽  
Distributed Control Systems ◽  
Pressure Transducers ◽  
Application Specific

In an effort to improve efficiency, reliability and reduce costs, engineers are moving towards distributed control systems on trains, cars, planes and other systems in place of centralized control systems. In a distributed control system, sensors, processors and actuators are all located together at remote locations [1]. Distributed control systems require significantly less cabling which leads to weight reductions and therefore cost and energy savings. To implement distributed control, in many applications sensors and their electronics must be able to withstand higher temperatures. Kulite Semiconductor Products has therefore developed a high temperature amplifier to be coupled with high temperature pressure sensors. While the suitable sensing technologies have been under the development for some time, the development of an Application Specific Integrated circuit (ASIC) utilizing SOI technology is now introduced and optimized. This paper reports on the latest developments of the Silicon-On-Insulator (SOI) piezoresistive sensors, the SOI application specific integrated circuits (ASICs) and the high temperature packaging of the two together. The design of the latest miniature amplified-pressure transducers capable of operating reliably under extreme environmental conditions (in excess of 250°C and under accelerations of greater than 200g) is described in detail. The performance of such amplified pressure transducers is presented and indicates that ruggedized, piezoresistive transducers with excellent static and dynamic performance characteristics are capable of operation in extremely harsh, high temperature environments.

Trends in the development of flexible thermal protection systems for modern aircraft

2020 ◽  
pp. 10-21
Author(s):  
V. G. Babashov ◽  
◽  
N. M. Varrik ◽  
Keyword(s):  
High Temperature ◽  
Thermal Protection ◽  
Heat Removal ◽  
Operating Conditions ◽  
Passive Protection ◽  
Thermal Protection Systems ◽  
Heat Protection ◽  
Protection Systems ◽  
Protected Surface ◽  
Flexible Panels

The emergence of new types of space and aviation technology necessitates the development of new types of thermal protection systems capable of operating at high temperature and long operating times. There are several types of thermal protection systems for different operating conditions: active thermal protection systems using forced supply of coolant to the protected surface, passive thermal protection systems using materials with low thermal conductivity without additional heat removal, high-temperature systems, which are simultaneously elements of the bearing structure and provide thermal protection, ablation materials. Heat protection systems in the form of rigid tiles and flexible panels, felt and mats are most common kind of heat protecting systems. This article examines the trends of development of flexible reusable heat protection systems intended for passive protection of aircraft structural structures from overheating.

Ultra-High Temperature Ceramics (UHTCs) via Reactive Sintering

2007 ◽  
Vol 336-338 ◽  
pp. 1159-1163 ◽  
Author(s):  
Guo Jun Zhang ◽  
Wen Wen Wu ◽  
Yan Mei Kan ◽  
Pei Ling Wang
Keyword(s):  
Phase Composition ◽  
High Temperature ◽  
Oxidation Resistance ◽  
High Performance ◽  
Thermal Protection ◽  
Ambient Pressure ◽  
Stable Phase ◽  
Reactive Sintering ◽  
Dissociation Temperature ◽  
Monolithic Ceramics

Current high temperature ceramics, such as ZrO2, Si3N4 and SiC, cannot be used at temperatures over 1600°C due to their low melting temperature or dissociation temperature. For ultrahigh temperature applications over 1800°C, materials with high melting points, high phase composition stability, high thermal conductivity, good thermal shock and oxidation resistance are needed. The transition metal diborides, mainly include ZrB2 and HfB2, have melting temperatures of above 3000°C, and can basically meet the above demands. However, the oxidation resistance of diboride monolithic ceramics at ultra-high temperatures need to be improved for the applications in thermal protection systems for future aerospace vehicles and jet engines. On the other hand, processing science for making high performance UHTCs is another hot topic in the UHTC field. Densification of UHTCs at mild temperatures through reactive sintering is an attracting way due to the chemically stable phase composition and microstructure as well as clean grain boundaries in the obtained materials. Moreover, the stability studies of the materials in phase composition and microstructures at ultra high application temperatures is also critical for materials manufactured at relatively low temperature. Furthermore, the oxidation resistance in simulated reentry environments instead of in static or flowing air of ambient pressure should be evaluated. Here we will report the concept, advantages and some recent progress on the reactive sintering of diboride–based composites at mild temperatures.

Thermal Response and Ablation Research of EPDM Thermal Protection Material in Ramjet

2015 ◽  
Vol 1092-1093 ◽  
pp. 534-538
Author(s):  
Xiong Chen ◽  
Hai Feng Xue ◽  
Hua Liang
Keyword(s):  
Heat Transfer ◽  
Heat Load ◽  
Thermal Protection ◽  
Thermal Response ◽  
Transfer Model ◽  
Back Face ◽  
Ground Test ◽  
Simulation Results ◽  
Face Temperature ◽  
Scanning Electron

Thermal protection materials are required to preserve the metal components of motor that suffer severe heat load. The research on thermal response of insulation of ramjet combustion chamber was carried out by the ground test and numerical simulation. During the working time of the ramjet, the back-face temperature of the thermal protection material was measured. The scanning electron microscope of samples was investigated. The calculation of thermo-chemical flow was solved by the CFD software FLUENT to provide the heat load boundary for simulation of heat transfer of EPDM insulation. The heat transfer model was solved by the FEA software ANSYS. Comparison of the temperature profile at the ablating surface between calculation and measurement shows the two results agree with each other. The simulation results can provide the temperature rising trend of insulation in a certain extent.

scholarly journals Investigations on Quench Recovery Characteristics of High-Temperature Superconducting Coated Conductors for Superconducting Fault Current Limiters

Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 259
Author(s):  
Wei Chen ◽  
Peng Song ◽  
Hao Jiang ◽  
Jiahui Zhu ◽  
Shengnan Zou ◽  
...  
Keyword(s):  
High Temperature ◽  
Smart Grids ◽  
Recovery Time ◽  
Coated Conductors ◽  
Transfer Model ◽  
Fault Current ◽  
High Temperature Superconducting ◽  
Fault Current Limiters ◽  
Recovery Characteristic ◽  
The Impact

Superconducting fault current limiters (SFCLs) are attracting increasing attention due to their potential for use in modern smart grids or micro grids. Thanks to the unique non-linear properties of high-temperature-superconducting (HTS) tapes, an SFCL is invisible to the grid with faster response compared to traditional fault current limiters. The quench recovery characteristic of an HTS tape is fundamental for the design of an SFCL. In this work, the quench recovery time of an HTS tape was measured for fault currents of different magnitudes and durations. A global heat transfer model was developed to describe the quench recovery characteristic and compared with experiments to validate its effectiveness. Based on the model, the influence of tape properties on the quench recovery time was discussed, and a safe margin for the impact energy was proposed.

scholarly journals A Satellite-Based Assessment of Upper-Tropospheric Water Vapor Measurements during AFWEX

2009 ◽  
Vol 48 (11) ◽  
pp. 2284-2294 ◽  
Author(s):  
Eui-Seok Chung ◽  
Brian J. Soden
Keyword(s):  
Water Vapor ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Raman Lidar ◽  
Test Bed ◽  
Upper Troposphere ◽  
Brightness Temperatures ◽  
Radiation Test ◽  
Humidity Measurements ◽  
Atmospheric Radiation Measurement

Abstract Consistency of upper-tropospheric water vapor measurements from a variety of state-of-the-art instruments was assessed using collocated Geostationary Operational Environmental Satellite-8 (GOES-8) 6.7-μm brightness temperatures as a common benchmark during the Atmospheric Radiation Measurement Program (ARM) First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment (FIRE) Water Vapor Experiment (AFWEX). To avoid uncertainties associated with the inversion of satellite-measured radiances into water vapor quantity, profiles of temperature and humidity observed from in situ, ground-based, and airborne instruments are inserted into a radiative transfer model to simulate the brightness temperature that the GOES-8 would have observed under those conditions (i.e., profile-to-radiance approach). Comparisons showed that Vaisala RS80-H radiosondes and Meteolabor Snow White chilled-mirror dewpoint hygrometers are systemically drier in the upper troposphere by ∼30%–40% relative to the GOES-8 measured upper-tropospheric humidity (UTH). By contrast, two ground-based Raman lidars (Cloud and Radiation Test Bed Raman lidar and scanning Raman lidar) and one airborne differential absorption lidar agree to within 10% of the GOES-8 measured UTH. These results indicate that upper-tropospheric water vapor can be monitored by these lidars and well-calibrated, stable geostationary satellites with an uncertainty of less than 10%, and that correction procedures are required to rectify the inherent deficiencies of humidity measurements in the upper troposphere from these radiosondes.

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