Papers by Keyword: Temperature Measurement

Abstract:

In this paper ,the method of the fluorescence lifetime (FL) in fluorescence optical fiber temperature sensor is used to measure the temperature. During the fluorescence information processing , because of existence of the system noise interference, measurement reliability of fluorescence lifetime has been greatly affected, thereby reducing the temperature measurement precision. This paper presents an improved wavelet threshold de-noising method to signal processing, which improves the signal-to-noise ratio and increases the measurement of fluorescence lifetime precision, reduce the error of temperature measurements at the same time. The experimental results demonstrate that this method is effective.

Abstract: A method for judging the gray property of flames based on spectral analysis and the two-color method for determining the temperature and emissivity of flame has been demonstrated. A calibrated spectrometer system was used for the data acquisition of the radiation intensity profile of a flame over a range of wavelengths (200 – 1100 nm). The wavelength range that meets the gray body assumption, in which the emissivity can be assumed as a constant, can be determined from the emissivity profile obtained by spectral analysis and the two-color method. Then the temperature and emissivity of the flame and their relative mean square deviations were calculated within that range. Experiments were conducted on pulverized coal-fired flames in a commercial 300MW boiler furnace. The results show that the coal-fired flame can be assumed as gray body between 500 nm and 1000 nm, and the temperature and emissivity calculation results of coal-fired flames are found to be in reasonable agreement with results using other methods from the literature.

Abstract: Thermoelectric couple was employed in traditional airplane engine temperature measurement system with the disadvantages of large size,heavy weight,big error and slow response.This paper presents a new kind of real—time temperature measurement system using laser diode InGaAs/I as light source,and using pyroelectric detector LiTa03 as optical receiving unit and using a microprocessor as signal processing center.This instrument consists of three parts:optical emitting and receiving system,signal amplifying and controlling system,and display system。The principle and structure of the system are introduced.Experimental results of airplane engine real—time temperature measurement show that temperature measurement accuracy and response time conform to our requirement in the range of 300°C一800°Cand agree with prediction of theory.All these prove that the design is correct.

Abstract: This paper proposes a temperature measuring method of low cost and stable precision based on platinum resistance. RC discharge circuit is composed of platinum resistor and fixed capacitor,the discharge time of fixed capacitance in the circuit is used for calculating the platinum resistance temperature resistance. The experimental results show that this is a simple and low cost method .

Abstract: The technology of fluorescent optical fiber temperature measurement has been used in many fields to accurately measure the variations of temperature, especially in some extreme environment, such as strong electromagnetic interference under, high voltage conditions. Wavelet analysis is the most frequent method used for signal processing in this technology. This method has excellent local characteristics and its precise of processing is high, whereas its result relies heavily on the selection of the wavelet basis, and has certain limitation. In this paper, a novel approach for fluorescent signal processing based on Hilbert-Huang transform is presented. A given signal is decomposed into a collection of intrinsic mode functions (IMF) by empirical mode decomposition, then Hilbert spectral analysis is performed for each of the IMF. According to the difference of signal and noise characteristics, HHT can generate adaptive modal functions and remove the noise from signal effectively, so that the signal to noise ratio can be improved. The result of experiment shows that HHT features convenient usage, fast processing and high resolution in time and frequency domains.

Abstract: A method is described to measure temperature on rake face and flank face during high speed milling through the combination of using a non-contact infrared pyrometer and drilling two holes in the workpiece. One of the holes was vertical to the direction of feed for measuring the temperature of rake face, and the other was parallel to the direction of feed for measuring the temperature of flank face. The holes enabled probe beam of the pyrometer to go through them to reach the tool surface directly. The method avoids drilling any hole in the tool and can be used to measure the interface temperature directly. This technique has potential application in monitoring tool temperature and analyzing tool wear during machining of difficult-to-cut materials.

Abstract: Modern tunnel structures are presently implemented primarily by conventional excavation, using the New Austrian Tunneling Method. Two linings are usually used to support the excavated area. The primary tunnel lining serves for consolidation of the extracting during tunneling and the secondary tunnel lining ensures the safe use of the structure during its life time. The design and evaluation of the tunnel lining is a comprehensive process that involves a lot of input conditions. We are not always able to define these inputs exactly. In order to specify the amount of secondary lining load, we must know not only the load by the rock but also e.g. the hydrostatic load and deformation behavior of concrete during its aging. The lining is also influenced by local climatic conditions. It is necessary to include effects of various temperatures on the lining in our design. The measurements carried out in the already completed structures serve us for a more exact determination of these temperatures. Based on the results from these measurements, we can determine the distribution of temperatures in the profile and the behavior of the construction versus the climate change more exactly. Monitoring the temperature development takes a long time. The specification of this behavior should lead to a material saving when new constructions are designed.

Abstract: Application of polycrystalline diamond compact (PDC) based cutting tools for hard rock excavation in mining and construction industries has increased significantly in recent years due to their super hardness, superb thermal conductivity and long life durability. Super Material Abrasive Resistant Tool (SMART*CUT) technology has been developed by CSIRO (Commonwealth Scientific and Industrial Research Organisation) in the last 15 years, which includes the replacement of tungsten carbide (WC) tips of the conventional picks with thermally stable diamond composite (TSDC) tips, attachment of the TSDC tips to steel tool bodies with CSIRO’s worldwide patented bonding technology. The wear characteristics of TSDC cutting elements have been investigated previously. In this paper, the preliminary results of cutter forces and resultant angle of SMART*CUT picks were compared with that of traditional WC picks. A tri-axial force dynamometer and a data acquisition system were used to measure the cutter forces. Besides, the cutting area temperature during cutting process was continuously measured by a FLIR SC7600M thermal infrared camera and the recorded data were processed by Altair Software.

Abstract: The processes of spinning and flow forming of hard metal sheets made from nickel superalloy INCONEL can be realized cold or with heating - e.g. by a induction or laser. When metal sheet is heated it is necessary to measure the temperature field on heated area, because its determines the deformation susceptibility. To control the temperature field pyrometers and infrared cameras are used. Due to strong changes in the surface of a formed material, under temperature influence (oxidation) and the action of the forming rolls, it is necessary to determine the emissivity coefficient values as a function of temperature and surface conditions. The paper presents the concept of determining these values, as well as an alternative technique for measuring temperature field, based on the methods of image analysis.

Abstract: In order to overcome the shortcomings of the traditional temperature measurement method which can only acquire the single point temperature or local temperature in the production process of roller kiln, In this paper, according to the principle of colorimetric temperature measurement, using the method of image preprocessing, designed a temperature measurement system based on CCD image sensor. The system can monitor and measurement the internal temperature of the roller kiln, and can obtain the global distribution of temperature field. According to the standard value method ,the system is calibrated using a blackbody furnace, to increase the detection precision and accuracy of temperature.The experimental results show that the system has high accuracy, can real-time reflect the global temperature field distribution of the roller kiln ,and the system has the great potential of industrial application.