Download or read book A Fiber Optic Probe Design for Combustion Chamber Flame Detection Applications Design Criteria Performance Specifications and Fabrication Technique written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-19 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper documents the design and development of the fiber-optic probes utilized in the flame detection systems used in NASA Langley Research Center's 8-Foot High Temperature Tunnel (8-ft HTT). Two independent flame detection systems are utilized to monitor the presence and stability of the main-burner and pilot-level flames during facility operation. Due to the harsh environment within the combustor, the successful development of a rugged and efficient fiber-optic probe was a critical milestone in the development of these flame detection systems. The final optical probe design for the two flame detection systems resulted from research that was conducted in Langley's 7-in High Temperature Pilot Tunnel (7-in HTT). A detailed description of the manufacturing process behind the optical probes used in the 8-ft HTT is provided in Appendix A of this report. Borg, Stephen E. and Harper, Samuel E. Langley Research Center NASA/TM-2001-211233, L-18121, NAS 1.15:211233

Download or read book A Fiber Optic Probe Design for Combustion Chamber Flame Detection Applications Design Criteria Performance Specifications and Fabrication Technique written by and published by . This book was released on 2001 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A FIBER OPTIC PROBE DESIGN FOR COMBUSTION CHAMBER FLAME DETECTION APPLICATIONS DESIGN CRITERIA PERFORMANCES NASA TM 2001 211233 DEC written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Fiber Optic Probe Design for Combustion Chamber Flame Detection Applications Design Criteria Performance S NASA written by and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NASA Langley Scientific and Technical Information Output 2001 written by and published by . This book was released on 2002 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book High Temperature Tolerant Optical Fiber Inline Microsensors by Laser Fabrication written by Tao Wei and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Fiber sensors are particularly attractive for harsh environment defined by high temperature, high pressure, corrosive/erosive, and strong electromagnetic interference, where conventional electronic sensors do not have a chance to survive. However, the key issue has been the robustness of the sensor probe (not the fiber itself) mostly due to the problems stemmed from the traditional assembly based approaches used to construct fiber optic sensors. For example, at high temperatures (e.g., above 500°C), the thermal expansion coefficient mismatch between different composited parts has a high chance to lead to sensors' malfunction by breaking the sensor as a result of the excessive thermo-stress building up inside the multi-component sensor structure. To survive the high temperature harsh environment, it is thus highly desired that the sensor probes are made assembly-free. We are proposing to fabricate assembly-free fiber sensor probes by manufacturing various microstructures directly on optical fibers. This dissertation aims to design, develop and demonstrate robust, miniaturized fiber sensor probes for harsh environment applications through assembly-free, laser fabrication. Working towards this objective, the dissertation explored three types of fiber inline microsensors fabricated by two types of laser systems. Using a CO2 laser, long period fiber grating (LPFG) and core-cladding mode interferometer sensors were fabricated. Using a femto-second laser, an extrinsic Fabry-Perot interferometric (EFPI) sensor with an open cavity was fabricated. The scope of the dissertation work consists of device design, device modeling/simulation, laser fabrication system setups, signal processing method development and sensor performance evaluation and demonstration. This research work provides theoretical and experimental evidences that laser fabrication technique is a valid tool to fabricate previously undoable miniaturized photonic sensor structures, which can avoid complicated assembly processes and, as a result, enhance robustness, functionality and survivability of the sensor for applications in harsh environments. In addition, a number of novel optical fiber sensor platforms are proposed, studied and demonstrated for sensing and monitoring of various physical and chemical parameters in high temperature harsh environments"--Abstract, leaf iii

Download or read book Fiber Optic Sensors and Systems written by and published by Information Gatekeepers Inc. This book was released on with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fabrication of Silicon Microprobes for Optical Near Field Applications written by Phan Ngoc Minh and published by CRC Press. This book was released on 2018-10-08 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of near-field optics marked a major advance in microscopy and our ability to develop nanoscale technologies. However, the tapered optical fiber widely in use as the optical near-field probe has serious limitations in its fabrication, its optical transmission efficiency, and its use in arrays. Fabrication of Silicon Microprobes for Optical Near-Field Applications reports on several technological approaches to using silicon micromachining techniques for fabricating microprobes without the drawbacks of conventional optical fiber probes. The authors have developed a simple, effective method for batch-process production of silicon cantilevered probes with apertures as small as 20 nanometers. They have investigated in detail the probes' optical performance characteristics and show how the silicon probes overcome the limitations of the optical fiber probes in terms of production throughput, optical throughput, reproducibility, simplicity of instrumentation, and mechanical performance.

Download or read book Fiber Optic Sensors written by David A. Krohn and published by . This book was released on 1989 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fiber Optics in Aerospace Vehicle Hazard Detection written by Alan Cutler Traub and published by . This book was released on 1962 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: Light-transmitting glass fiber bundles in various configurations have been subjected to extensive optical, mechanical and thermal testing and to various other analyses. The report provides im portant information on fiber optic characteristics as well as design considerations for developing optimum systems. System configurations are rec ommended which would extend the capabilities of the basic fiber bundle in meeting the diverse requirements of installation, operation and maintenance in various applications. An experi mental fiber optic system for flame detection is described. It uses a 25 foot long bundle and incorporates a special photoelectric detection system and other embodiments of our findings.

Download or read book Development of Optical Fiber based Sensing Devices Using Laser Microfabrication Methods written by Seyed Hamidreza Alemohammad and published by . This book was released on 2010 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: The focus of this thesis is on the development of sensing devices based on optical fiber sensors, specifically optical Fiber Bragg Gratings (FBG), using laser microfabrication methods. FBG is a type of optical fibers whose spectral response is affected by applied strain and temperature. As a result, it can be calibrated for the measurement of physical parameters manifesting themselves in the changes of strain or temperature. The unique features of optical fiber sensors such as FBGs have encouraged the widespread use of the sensor and the development of optical fiber-based sensing devices for structural measurements, failure diagnostics, thermal measurements, pressure monitoring, etc. These features include light weight, small size, long-term durability, robustness to electromagnetic disturbances, and resistance to corrosion. Despite the encouraging features, there are some limitations and challenges associated with FBGs and their applications. One of the challenges associated with FBGs is the coupling of the effects of strain and temperature in the optical response of the sensors which affects the reliability and accuracy of the measurements. Another limitation of FBGs is insensitivity to the index of refraction of their surrounding medium. In liquids, the index of refraction is a function of concentration. Making FBGs sensitive to the index of refraction and keeping their thermal sensitivity intact enable optical sensors with the capability of the simultaneous measurement of concentration and temperature in liquids. Considering the unique features of FBGs, embedding of the sensors in metal parts for in-situ load monitoring is a cutting-edge research topic. Several industries such as machining tools, aerospace, and automotive industries can benefit from this technology. The metal embedding process is a challenging task, as the thermal decay of UV-written gratings can starts at a temperature of ~200 oC and accelerates at higher temperatures. As a result, the embedding process needs to be performed at low temperatures. The objective of the current thesis is to move forward the existing research front in the area of optical fiber sensors by finding effective solutions to the aforementioned limitations. The approaches consist of modeling, design, and fabrication of new FBG-based sensing devices. State-of-the-art laser microfabrication methods are proposed and implemented for the fabrication of the devices. Two approaches are adopted for the development of the FBG-based sensing devices: the additive method and the subtractive method. In both methods, laser direct microfabrication techniques are utilized. The additive method deals with the deposition of on-fiber metal thin films, and the subtractive method is based on the selective removal of materials from the periphery of optical fibers. To design the sensing devices and analyze the performance of the sensors, an opto-mechanical model of FBGs for thermal and structural monitoring is developed. The model is derived from the photo-elastic and thermo-optic properties of optical fibers. The developed model can be applied to predict the optical responses of a FBG exposed to structural loads and temperature variations with uniform and non-uniform distributions. The model is also extended to obtain optical responses of superstructure FBGs in which a secondary periodicity is induced in the index of refraction along the optical fiber. To address the temperature-strain coupling in FBGs, Superstructure FBGs (SFBG) with on-fiber metal thin films are designed and fabricated. It is shown that SFBGs have the capability of measuring strain and temperature simultaneously. The design of the sensor with on-fiber thin films is carried out by using the developed opto-mechanical model of FBGs. The performance of the sensor in concurrent measurement of strain and temperature is investigated by using a customized test rig. A laser-based Direct Write (DW) method, called Laser-Assisted Maskless Microdeposition (LAMM), is implemented to selectively deposit silver thin films on optical fibers and fabricate the superstructure FBGs. To attain thin films with premium quality, a characterization scheme is designed to study the geometrical, mechanical, and microstructural properties of the thin films in terms of the LAMM process parameters. A FBG, capable of measuring concentration and temperature of liquids is developed, and its performance is tested. Femtosecond laser micromachining is successfully implemented as a subtractive method for the sensor fabrication. For this purpose, periodic micro-grooves are inscribed in the cladding of regular FBGs so as to increase their sensitivity to the concentration of their surrounding liquid while keeping their thermal sensitivity intact. This type of sensors has the potential for applications in biomedical research, in which the in-situ measurement of the properties of biological analytes is required. Another accomplishment of this thesis is the development of FBG sensors embedded in metal parts for structural health monitoring using low temperature embedding processes. In this regard, the opto-mechanical model is extended to predict the optical response of the embedded FBGs. The embedding process involves low temperature casting, on-fiber thin film deposition, and electroplating methods. The performance of the embedded sensors is evaluated in structural loading and thermal cycling.

Download or read book Fiber Optic Sensor Specification Guidelines for Aerospace Applications written by AS-3 Fiber Optics and Applied Photonics Committee and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: ARP6366 defines a comprehensive and widely-accepted set of specification guidelines to be considered by those seeking to use or design fiber optic sensors for aerospace applications. Some of the most common applications for fiber optic sensing within aerospace include inertial guidance and navigation (gyros) and structural monitoring (temperature, strain, and vibration sensing). Common sensor infrastructure elements include: transmitting and receiving opto-electronics (e.g., sources and receivers); multiplexing and demultiplexing optics; optical cabling; and signal processing (both hardware and firmware/software). Use of fiber optic sensor systems in the aerospace industry is expected to grow as the benefits and unique sensing solutions are understood. Guidance is needed for writing fiber optic sensor specifications to supply a comprehensive and widely-accepted vocabulary, parameters, and practices for fiber optic sensors for aerospace applications. Adoption of fiber optic sensors on aerospace platforms will benefit from improved coordination between developers, specifiers, program managers, and end users.

Download or read book Fiber Optic Sensor Technology and Applications written by and published by . This book was released on 2005 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design and Evaluation of a Fiber Optic Probe as a Means of Subsurface Planetary Exploration written by Robert Paul Pilgrim and published by . This book was released on 2013 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Optical Probe for Regolith Analysis (OPRA) is an instrumentation concept designed to provide spectroscopic analysis of the near subsurface of unconsolidated regolith on bodies such as moons, asteroids and planets. Below a chemically altered surface may lay the geological history in the form of stratigraphy that is shielded from degradation due to harsh external environments. Most of what we know about our solar system comes from remote platforms, such as satellites that are deployed into orbit around the target body. In the case of Mars, we have had several successful landers and rovers however, with the exception of the Mars Science Laboratory that just drilled its first hole, the complexity of subsurface excavation has limited the extent of subsurface exploration to simple scoops deployed on the ends of robotic arms which, by their very nature, will erase any stratigraphy that it may be digging into. The OPRA instrumentation concept allows for an integrated, lightweight and simple apparatus for subsurface exploration via a small, spike like structure which contains integrated optical fibers coupled to small windows running down the length of the probe. Each window is connected to a spectrometer housed onboard the deploying spacecraft. Each window is separately interrogated via the spectrometer over the wavelength range 1-2.5 nm to produce a spectroscopic profile as a function of depth. This project takes the Technology Readiness Level (TRL) of the OPRA instrumentation concept to level 3, which is defined by NASA to be the demonstration either analytically or experimentally of the proof of concept for critical functions of the proposed instrument. Firstly, to demonstrate that optical fibers are feasible for this type of application, we report on the techniques used by NASA to space qualify optical fibers. We investigate the optical performance of several fiber optic bundle configurations, both experimentally and numerically, to help optimize bundle performance. Optical bundles were then spectrally validated via a series of spectral comparisons between standardized reflectance spectroscopy targets and spectra obtained with the bundles. We also report on the integration of fiber optical bundles into other research and experimental results from several other groups within our research teams to obtain spectra under a more "space like" environment. Finally, the probe housing structural performance was investigated via finite element analysis, using probe penetration forces derived from data analysis of experimentation conducted by the Apollo lunar missions, and investigations into a mechanical analogue for the Martian regolith.

Download or read book Design and Fabrication of an Optical Fiber Interrogation Instrumentation System written by Srirajasingam Vahesan and published by . This book was released on 2006 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fiber Optic Engineering Sensor System Design Review Report written by NKF ENGINEERING INC RESTON VA. and published by . This book was released on 1987 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: A meeting was held, as required by CDRL A002 of Contract No. N00014-87-C-2032 and conducted per MIL-STD-1532, to orally present the findings and recommendations contained in the FOESS Phase I Preliminary Design Review Data Package, for formal review by NRL. The ray paths shown represent displacement effects only. Because the spherical mirror acts as a lens, capturing all of the propagating modes emanating from the fiber and imaging them onto the mirror, there is no modal dependence. Imaging however, increases alignment dependence requiring the use of misalignment insensitive designs, e.g. HAML. There is presently no specific data on the performance of the HAML since it is at present a concept design only. The temperature dependence of the GACPV's force-to-displacement transfer function can be reduced or eliminated by selecting a sufficiently large force constant for the optical diaphram. Gases making the transducer suitable for operation over large temperature ranges would be indentified during design and construction. The key-term Good does not mean that a particular transducer will meet a MIL-SPEC. The terms used in the table are relative only to the four candidate transducers included and are derived from realistic assessments of their potential qualities. Construction and testing is necessary to verify the comparisons.