Optical-electronic System Research Articles

On the temperature and reaction rate of burning pulverized fuels

A two-color pyrometer technique has been used to measure the temperature of burningpulverized fuel particles flowing in dilute suspension on the centerline of a laminar flow reactor. The transparent reactor is fed by a premixed flat flame fueled with CH 4 −H 2 −O 2 −N 2 mixtures, which permit widely variable post-flame temperatures and oxygen concentrations to be obtained. The two-color system employs an optical-electronic system which includes two monochromators to acquire light emission intensity at two wavelengths simultaneously from individual burning particles passing through a 1 mm square area on the centerline of the reactor. Planck's law and the gray body assumption (verified here by measurements) are used to compute particle temperatures, and the average temperature is then determined by averaging the values for some 500 individual particles. Particle temperatures have been determined for various gas temperatures over a range ofoxygen mole fractions from 0 to 0.2 for size-graded (90 μm mean diameter) samples of a petroleum coke and a flash pyrolysis char. Particle burning rates per unit external surface area were determined from the measured temperatures by a heat balance analysis. The functional variation in burning rate with temperature was then used to infer whether the burning rate was controlled by chemical rates (Zone I), the combined effects of chemistry and pore diffusion (Zone II), or bulk diffusion (Zone III). For the petroleum coke, both zone I and Zone II conditions were observed, and chemical rate coefficients for each zone were derived. For the char, Zone II and a transition to Zone III conditions were observed, and a chemical rate coefficient for Zone II was derived. Reaction orders and activation energies were in the range expected from previous oxidation studies, and the chemical rates for both samples were in good agreement with previous measurements by a different method in another laboratory. The results show that careful temperature measurements can provide a sensitive method for the determination of pulverized fuel burning rates.

Integrated optical detector array, waveguide, and modulator based on silicon technology

An integrated optical (IO) hybrid circuit consisting of a photodetector array, waveguide, and acousto-optic modulator on a common silicon substrate has been fabricated. This IO hybrid circuit is a major step in the development of a combination optical-electronic processing system. In this device an array of p-n junction photodiodes was fabricated on a 2-in silicon wafer and a 7059 glass waveguide film sputtered over an SiO/SUB 2/ insulating layer on the wafer. Another SiO/SUB 2/ layer was deposited under the transducer electrode. The transducer was a 40-MHz lithium niobate rotated Y-cut crystal. A prism was used to couple in the light beam from a 5 mW He-Ne laser. The guided light beam was directed at one of the diodes in the array and pulsed RF signals were applied to the transducer. Oscillator frequencies of 40 MHz and 120 MHz were separately applied. Modulation depths of greater than 25 percent were produced. The fabrication of the optical guide photodiode and electrical interconnections on a single silicon wafer utilized standard IC fabrication techniques.

Temperature Measurement of Flame in a Gasoline Engine : 1st Report, Measurement of Average Temperature

One method to measure the instantaneous flame temperature within the cylinder of a gasoline engine by means of the absolute radiation method is proposed. The radiation energy of D-line emitted from a trace of sodium, which is added to fuel, is measured by an optical-electronic system. Then, the measured energy is converted into the equivalent black body temperature. This temperature may be considered as the flame temperature which is averaged through an optical path in the luminous flame zone. In the process of conversion, the half-width of D-line is determined experimentally and the number of Na atoms radiating in the optical path is evaluated theoretically. As the optical system, a quartz window, 4 limiting diaphragms, an interference filter and a fiber-scope are arranged in order. And a light beam having 1 mm in diameter is introduced to a photo-multiplier by means of the fiberscope. By this technique, the flame temperature in CFR engine is measured under various operating conditions.

An automatic patient-contour measuring apparatus.

All optical-electronic system has been developed as a new approach to the task of measuring and recording patient contours. The system projects 2 slightly convergent light beams onto the patient. The resultant light spots are detected by a photomultiplier tube that is located behind a rotating slit wheel. The photomultiplier produces pulses that are analyzed to generate a voltage proportional to distance. An extremely stable system results from the use of time-dependent pulsed circuitry. The voltage generated by the system is used to drive the pen of a polar-coordinate recorder, while its table is synchronized to the rotation of the cobalt 6o unit in which the optical portion of the system is mounted.The polar recorder has 2 channels, one of which is used to plot patient contours, while the other is used in conjunction with a transmission ionization chamber to record transmission dose or the equivalent homogeneous contour. The recorder is mounted in a portable utility cabinet and can be used in the ther...

Optical-electronic system for transmitting the data of an electric measuring instrument

Description of a device transmitting, through light pulses, the data of an electric measuring instrument placed in a high voltage container. Its essential feature is its high stability, obtained by eliminating the dependence of the oscillator frequency from the characteristics of the oscillator tube.