DETERMINATION OF THE FREQUENCY OF OSCILLATIONS IN THE AUTODYNE'S SENSOR UNDER THE REGULAR AND CASUAL TEMPERATURE MODE VARIATIONS.

摘要

The sensor [1] is shown on (figurel) is mounted in an orifice of the reactor wall. Antenna (2) is inward to the reactor; its conductivity depends on the permittivity of a high-temperature working body (7) and transforms to an autodyne frequency. Heating of the sensor is realized by the working body (3,4,5,) through the antenna surface. Largest part of the sensor's body is outside of the reactor and cools through the sidewalls. Variations of resonator length, permittivities of its filling, and also capacity of the diode (6) mainly influence the frequency of generation. The static temperature mode, influence to frequency variations and possible errors of the sensor value are investigated in [2]. Error, that is most difficult to compensate for, is caused by the regular temperature variations at the starting time. Theoretical estimations of this magnitude are presented in this paper. The investigation of a casual error is continued. The working body of the sensor (with a resonator), which is represented by a linear narrow-band quadripole, carries out a temperature transformation into a frequency shift. Its properties are based on the wellknown thermophysics regularities. The heat exchange between working body and antenna happens by radiation under the law of Newton. The rough heat causes temperature waves in the working body of the sensor, which propagate with strong attenuation and with velocities, that depend on frequency. The mathematical investigations include: (1)The approximation of a temperature's curve of growth in the reactor T(t)and its Fourier-expansion (2)Determination of an impulse characteristic of 《quadripole》 h(t) in any cross-section of the sensor (3)Convolution of functions T(t) and h(t-τ)(4)Integration by the sensor's (resonator) length along a coordinate x ∈ 0, L (5)The translation into the frequency change The investigated examples have shown that the process of a sensor's warming up to stationary temperature is longer than the starting time. Frequency of generation lowering under the heating happens with a big delay, which does not enable to monitor the temperature in practical applications. Therefore, the compensation of the error under the primary, and secondary processing is hampered. A solution for this problem is the development of a computer model, which is taking into account, all obtained correlations. The influence of the fluctuation's variations of temperature is considered with reference to the thermoenergetics unit, the significance of a spectral density and average quadrate of frequency fluctuations is obtained. The new theory allows measuring the temperature in the reactor with sufficient high accuracy.