RU1777009C - Gas flow temperature measurement method - Google Patents

Abstract

SUMMARY OF THE INVENTION: Two tubes are installed in parallel in a gas stream, one of which is cooled to a temperature Tst different from the temperature Tst in the second cooled tube by an amount of A T of at least 425 K. Gas is sucked through the tubes and the temperature TI and Ti of the chilled gas in each tube are measured at the same distance from its inlet end. The gas temperature Tg is determined by the formula. 2 ill.

Description

The invention relates to the field of thermometry and can be used to measure gas temperature.

A known method for determining the temperature of a gas is based on solving the inverse problem of heat transfer in the initial section of an intensely cooled channel. The method consists in calculating (restoring) the gas temperature Tg by measuring the temperatures TI and T2 of the cooled gas in sections Xi and X2 of the installation of primary thermal converters along the length of the channel X at a gas flow velocity W in the measuring channel and measuring the temperatures Ti and Tg in the same cross-sections at a changed gas flow velocity W in the channel (the channel wall temperature TCT being considered constant and to be measured) 1.

This method does not provide sufficient measurement accuracy due to the error caused by a change in the gas flow rate in the measuring channel.

The closest to the invention in technical essence and the achieved result is a method for determining the temperature of the gas stream, which consists in measuring the temperature of the inner surface of the walls of two cooled tubes installed in parallel in a gas stream, followed by suction of gas from them, measuring the temperature Ti and Ti of chilled gas in each the tube, at the same distance from its inlet end, and determining the gas temperature from the measured values of 2.

A disadvantage of the known method is its low accuracy.

The purpose of the invention is to increase the accuracy of determining gas temperature.

The goal is achieved in that in the known method, one of the tubes is cooled to a temperature Tc. that differs from the temperature Tst in the second tube by a DT of at least 425 K, and the temperature Tg of the gas stream is determined by the formula:

with/

with

Xi

vi

Xj

LTD

Tr tc

Ti-Tc

1 - (Ti-Ti) (TcT-TcT T

(D

Measurement of the temperatures Ti and Ti at two different values of the channel wall temperature Tst and JCT and determination of Tg by formula (1) allows us to take into account the change in the heat transfer coefficient from gas to the walls along the channel length and eliminate the dependence of the result of the restoration of the gas temperature Tg on the change in the Stanton number at options for gas flow rate in the measuring channel.

Fig. 1 shows an apparatus for implementing the method; figure 2 is a section aa in figure 1.

The device comprises a housing 1 with a partition 2 dividing the housing along a generatrix into two sealed identical halves in which two pipes 3 of the measuring channels are located; a pipe 4 of an installation channel interfaced with pipes 3 in a working section; thermocouples 5 equally buried in the measuring channels 3; pipes 6 for supplying a cooling medium and a nozzle 7 for its discharge.

Measurement of the gas temperature by the device shown in Fig. 1 according to the claimed method is carried out as follows. A device with two identical cooled tubular measuring channels 3 is introduced into the gas, the first measuring channel 3 is cooled, for example, with water, and the second with air, the reference value of the wall temperature Tst of the first channel 3 is measured, the wall temperature Tst of the second channel 3 having thanks dr0

5

0

5

0

5

To this cooling, the changed conditions of heat transfer between the gas and the walls as compared with the first channel move the block of thermal converters 5 to the entrance to the channel, until the temperature of one of them approaches the softening temperature of the ash of this fuel, the gas temperature TI is measured in the section of the channel 3 with water cooling and the temperature of the Ti gas in the air-cooled duct. I record the values of Ti, Ti, Tst, Tst, and from equation (1) determine

the value of Tg.

At a gas temperature Tg of 2000 K, the measured values of the temperatures included in the calculated dependence are equal to; Ti 1700K; Ti 1600 K, Tst 300 K; Tst 725 K. The relative error in the reduction of Tg is 1.2%.

Claims (1)

SUMMARY OF THE INVENTION A method for determining the temperature of a gas stream, which consists in measuring the temperature of the inner surface of the walls of two chilled tubes installed in parallel in a gas stream, then sucking gas therefrom, measuring the temperature Ti and Ti of the chilled gas in each tube at the same distance from its inlet end and determining the gas temperature from the measured values, characterized in that, in order to increase accuracy, one of the tubes is cooled to a temperature Tst. differing from the temperature ТСт in the second tube by the value А Т not less than 425 ° К, and the gas flow temperature is determined by the formula Tg Tst + Ti -T st 1 - (T1 -Tl) (TcT -Tst) jyz% J 3.tt Z3 -JЈЈJ№.tfJЈ 1 figure 1 Aa FIG. 2