Author: David Viveros Salazar
Publisher:
ISBN:
Category :
Languages : en
Pages :

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A comparison of scanned-DAS and scanned-WMS was completed within the context of a biomass gasification pilot scale facility, while scanned-DAS was implemented and optimized to increase sensing capabilities in the mixing volume (MV) of the 60 MW Interaction Heating Facility (IHF) at NASA Ames Research Center (ARC). In the biomass gasification study, a demonstration of in situ laser-absorption-based sensing of H2O, CH4, CO2, and CO mole fraction is reported for the product gas line of a biomass gasifier. Field measurements were demonstrated in a pilot scale biomass gasifier at WestBiofuels in Woodland, California. The performance of a prototype sensor was compared for the two sensing strategies, scanned-DAS and scanned-WMS. The lasers used had markedly different wavelength tuning response to injection current, which led to establishing guidelines for laser selection for sensor fabrication. The complications of using normalized WMS for relatively large values of absorbance and its mitigation are discussed. The laser absorption sensor provided measurements with the sub-second time resolution needed for gasifier control and more importantly provided precise measurements of H2O in the gasification products, which can be problematic for the typical gas chromatography sensors used by industry. The IHF at NASA ARC is a critical facility used to study and characterize thermal protection systems (TPS) of reentry spacecraft. The IHF generates an electrical arc to energize room temperature air, which is then forced through a converging-diverging nozzle. Material and model test pieces are then subjected to the stagnation environment of the flow stream. The efforts at ARC focused on characterizing the mixing of add-air in the MV of the IHF. Conditions in the IHF, in the mixing volume (MV) where this study focused its optical measurements, range from 5,000 to 7,000 K and 1 to 9 atm. Path-average line-of-sight measurements of temperature and enthalpy were inferred using an electronic atomic oxygen transition near 777 nm. The scanned-DAS sensor was optimized to capture high add-air and high-pressure conditions that previously had not been measurable. Optimization of the sensor allowed for fully resolved absorbance profile measurements at the maximum pressure test condition in the IHF MV. Enhanced sensor capabilities confirmed uniform flow and flat temperature immediately upstream of the arcjet's converging-diverging nozzle inlet. Less uniform and parabolic temperature profiles were observed immediately downstream of add-air injection. This arcjet facility implements injection of room temperature air, i.e. add-air, to tune the bulk and centerline enthalpy generated at the nozzle exit. Centerline temperatures at an axial location downstream of add-air injection confirmed the need for mixing beyond the MV entrance. Enthalpy measurements ranged from 16 to 27 MJ/kg and are in agreement with the IHF's current enthalpy measurement methods. This confirmed the observed reduction in achievable enthalpy after installation of the MV. Centerline measurements quantified the mixing process for various add-air conditions indicating an opportunity for enthalpy recapture. Axial locations of sufficient mixing were identified and provide a potential for reduction of the MV length and thus improved facility performance. Optimization of this sensor will enable future use by non-experts to provide critical data on the arcjet environment in the IHF, thereby enhancing arcjet test results and leading to greater reliability of spacecraft TPS designs.

Author: William VonDrasek
Publisher:
ISBN:
Category :
Languages : en
Pages : 128

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This work represents the collaborative effort between American Air Liquide and Physical Sciences, Inc. for developing a sensor based on near-IR tunable diode lasers (TDL). The multi-species capability of the sensor for simultaneous monitoring of CO, O2, and H2O concentration as well as gas temperature is ideal for in-situ monitoring on industrial furnaces. The chemical species targeted are fundamental for controlling the combustion space for improved energy efficiency, reduced pollutants, and improved product quality, when coupling the measurement to a combustion control system. Several add-on modules developed provide flexibility in the system configuration for handling different process monitoring applications. For example, the on-Demand Power Control system for the 1.5?m laser is used for high particle density exhaust streams where laser transmission is problematic. For long-distance signal collection a fiber optic communication system is used to reduce noise pick-up. Finally, hardened modules to withstand high ambient temperatures, immune to EMF interference, protection from flying debris, and interfaced with pathlength control laser beam shielding probes were developed specifically for EAF process monitoring. Demonstration of these different system configurations was conducted on Charter Steel's reheat furnace, Imco Recycling, Inc. (now Aleris International, Inc.) aluminum reverberatory furnace, and Gerdau Ameristeel's EAF. Measurements on the reheat furnace demonstrated zone monitoring with the measurement performed close to the steel billet. Results from the aluminum furnace showed the benefit of measuring in-situ near the bath. In this case, low-level furnace optimization was performed and demonstrated 5% fuel savings. Monitoring tests on the EAF off-gas demonstrated the level of industrialization of the sensor to survive the harsh EAF environment. Long-term testing on the EAF has been on-going for over 6 months with essentially zero maintenance. Validation of the TDL measurement on the EAF was confirmed by comparison with extractive sampling CO measurements.

Author: Chayan Mitra
Publisher:
ISBN:
Category : Science
Languages : en
Pages :

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The world has witnessed several step changes in living standards, productivity, growth, and innovation. We are currently witnessing a convergence of intelligent devices, intelligent networks, and intelligent decision making. Obtaining long-term accurate, in situ, and real time data from the machines is necessary for enabling the industrial Internet. This relies heavily on sensor systems. Development of robust sensors that can operate reliably in extreme environments will make it possible to gather data from previously inaccessible locations in the equipment. This will enable machine operators to monitor and optimize the performance of their machines. Diode laser-based diagnostics technology has found applications in a variety of areas and a versatile range of operating conditions. It has proven to be a strong and reliable technique for remote measurements of concentrations and temperatures in harsh environments. Some of the major challenges for implementation of these sensors in real world are machine vibrations, window clogging, cooling, et cetera In this chapter, the authors discuss about the application details and specific technologies suitable for the applications. Few case studies are considered, and the theoretical approach, algorithm development, and experimental validation are also discussed.

Author: Alan Fried
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 370

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Category :
Languages : en
Pages :

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Author: D. S. Baer
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Languages : en
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Author: Frank K. Tittel
Publisher: Springer
ISBN: 9783642022913
Category : Technology & Engineering
Languages : en
Pages : 0

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Special issue of the 7th International Conference on Tunable Diode Laser Spectroscopy, held July 13-17, 2009 in Zermatt, Switzerland. The purpose of these meetings was to report and discuss the progress that has been made in the technical development of diode lasers and their applications in areas of fundamental research as well as real world applications of the technology. This was accomplished in a format encouraging strong interaction between researchers, device developers and semiconductor laser manufacturers. The relevant technologies include the original lead salt lasers, near-infrared diode lasers and the latest developments in mid-infrared quantum and interband cascade lasers, as well as nonlinear optical schemes.

Author: V. Nagali
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Category :
Languages : en
Pages :

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Category : Forest reserves
Languages : en
Pages : 4

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Author: Suhong Kim
Publisher:
ISBN:
Category :
Languages : en
Pages : 130

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