SU1597600A1 - Method of determining temperature of suspended layer - Google Patents

Abstract

The invention relates to the field of temperature measurements and is intended to determine the temperature of a suspended layer, in particular, a fluidized bed and aero fountain beds, and improves the accuracy of temperature determination. A thermocouple is placed on a massive, temperature-controlled body and introduced into the test layer. After the steady state is established, the thermoconverter readings are recorded at different temperatures of the massive body, the average temperatures of the thermoconverter T _W @ and the corresponding mean deviations ΔТ _W @ are determined for each I temperature of the massive body, the dependence ΔТ _W @ (T _W @) is constructed, from which the body temperature T _in = T _W @ is determined at ΔТ _W @ = 0.

Description

The invention relates to temperature measurements and is intended to measure the average temperature of a suspended layer, in particular fluidized (boiling), and aero fountain layers, used in the power industry and chemical industry when burning and processing low-grade fuels, roasting ores, production of mineral fertilizers and other technological processes

The purpose of the invention is to improve the accuracy of temperature determination.

The essence of the method is as follows. A characteristic feature of fluidized systems is the presence of inhomogeneities in their structure — the so-called particle packets.

and bubbles. These moving irregularities in the structure of the fluidized bed are the cause of the pulsations of the instantaneous heat transfer coefficient of the body immersed in the bed. In particular, when moving close to the heat exchange surface of a packet of particles, the heat transfer coefficient is about the order of the heat transfer coefficient when the surface is washed with a bubble. Thus, for relatively short periods of time, the duration of which is approximately equal to l / f, where fp is the frequency of gravitational oscillations of the layer, there is a strong change in the heat transfer coefficient of the heat that is in heat exchange with the fluidized bed. Therefore, when

sd

the presence of heat flow between the surface of the massive solid and the core layer, temperature pulsations occur on the heat exchange surface, caused by changes in the heat transfer coefficient.

As the calculations show, the average value of the amplitude of the ripple ZIT. on the solid-fluid interface, the fluidized track is related to the average temperature of the thermal receiver T and the layer temperature T by the ratio

at

 W

- BT

eight

where B is a constant coefficient. From this expression it follows that

with RT yes. about t

eight

 W,

In order to find the desired temperature T., T. it is necessary to determine the unknown coefficients in the indicated equation, for which it suffices to obtain 2g-3 values

NIN gz t „. at h {

T iW:

than measurements of HRT - at temperatures T of the pad significantly lower T

(i, 2,3), it is possible to perform a CU thermodynamics

at

The method is carried out as follows.

A thermocouple, for example, a thermocouple is placed on a massive heat, the temperature of which can be changed in wide ranges. For this, for example, a massive body is supplied with channels through which the coolant flows, for example water with a certain temperature. Before inserting the thermal converter into the layer, a certain temperature of the massive body is established, stabilizing the flow rate of the heat transfer fluid through the layer. After introducing the thermal converter into the layer and establishing the stationary pair mode, the readings of the thermal converter T are recorded for some time (chosen arbitrarily), usually

0

five

0

on the order of ten periods of the thermoconverter signal offsets from the average value. Then establish a new temperature of the massive body, changing the flow rate of the coolant. After the stationary mode is established, the readings of the thermoconversion in the ly /.- are recorded, then changed again from the flow rate of the coolant and so the operations are repeated N times. The value of N is determined on the basis of the accuracy requirements and conditions of the specific process. 3-5 measurements are usually sufficient.

On the basis of the obtained results, the average values of Tuu are determined by mathematical methods and the corresponding deviations Tj.a. The dependencies-DT, T, are determined according to which the desired temperature is determined from

conditions

t a

T .... at 4 T,. ,,, 0,

W;

25 Formula

of

R e T e n i

0

five

,,

five

The method of determining the temperature of the suspended layer consisting in placing the thermoconverter in the test layer and recording the thermoconverter readings after reaching a stationary temperature, characterized in that, with increasing temperature determination, the thermoconverter is placed on a massive body with an adjustable temperature, the thermoconverter readings are recorded at different temperatures massive body, according to the recorded indications determine the average temperature t The thermoconverter T, and the corresponding mean deviations L T., of each i-th temperature ature of the massive body, builds the dependence AT. y ,. (T.), from. which determine the desired temperature T -

W;

pri and t VV, - oh,

Claims (1)

25 Formula a The method of determining the temperature of the suspended layer, which consists in the location of the thermal Converter in the way A thermoconverter, for example thermoelectric, is placed on a massive body, the temperature of which can be changed over a wide range. For this, for example, a massive body is provided with channels through which a coolant is passed, for example: water with a certain temperature. Before the introduction of the thermal converter into the layer, a certain temperature-specific temperature of the massive body is established, stabilizing the flow of heat carrier through it. After the thermoconverter is introduced into the layer and the stadium of the pair mode is established, the readings of the thermoconverter T ^ are recorded. for some time (chosen arbitrarily), the usually studied layer and recording the readings of the thermal converter after reaching a stationary temperature, characterized in that, in order to increase the accuracy of determining the temperature, the temperature is placed on a massive body with a controlled temperature, the temperature transducer is recorded at various temperatures of the massive body, the average temperature of the thermal transducer T _{w is} determined from the recorded readings. and the corresponding mean deviations .DT. ^ 'for each ith 45th temperature of a massive body, build the dependence <aT (T _w .), from. which determine the desired temperature Τθ = T _w . at.DT = 0,