SU1509635A1 - Heat flow sensitive element - Google Patents

Abstract

The invention can be applied in heat testing and process control systems. Compared with the Gardon sensor, the accuracy of measuring heat fluxes in the temperature range of 300 ÷ 1200 ° C is improved. On the inner surface of the measuring membrane, a heat-insulating heat-conducting cap is used, which is installed in the head part of the sleeve. The temperature of the body wall (sleeve) of the sensor during the measurement process is maintained equal to or close to the temperature of the wall of the test object. When determining the heat transfer coefficients, it is possible to exclude errors in the determination of the heat transfer coefficient associated with the rearrangement of the boundary layer. The sensor can be made with small dimensions (* 220 1 ÷ 6 mm and thickness δ = 2-5 mm), which allows its use in model tests and in industrial samples without disturbing the integrity of structural elements. Due to the lack of a cooling system, the installation and operation of the sensor is simple and convenient. 1 il.

Description

The invention relates to measuring instruments and can be used to measure the amount of heat in thermal devices used in all areas of the national economy.

The goal of ibrate is to increase accuracy.

The drawing shows the heat flux sensor, a general view.

The sensor contains a heat-conducting sleeve. I, in the head end part with the membrane installed 2, made of heat-conducting material. The membrane 2 is made in the form of a thin-walled disk with thickness about and peripherally connected to the end part of the sleeve 1 with the provision of thermal contact.

On the inner side of the membrane 2, sensors are installed to measure:, the surface temperature of the membrane 2, for example, thermoelectric: sensor C in the center of the membrane disk; sensor 4 - at the base of the membrane; sensor 5 - at the peripheral part of the membrane.

In the manufacture of membrane 2 from the chromel material, as SP00

, 3J509

A thermocouple is used to measure the temperature difference between the installation points of sensors 3 and 4, using thermoelectrodes of material, copel and or alumel.

In the head part of the sleeve 1 is placed a heat-conducting cap 6, made of a heat-conducting material, such as molybdenum, copper,

The cap 6 is installed with ensuring thermal contact with the head part of the sleeve facing the source of heat flow. Thermal contact is provided in the head of the warmest part of the sensor by applying landing 7. The cap 6 does not have thermal contact with the membrane 2.

The wall thickness of the cap 6 is related to the thermophysical characteristics of the material and the efficiency of thermal contact at the junction with: the sleeve 1. The thickness of the cap 6, the location of ska 7 is chosen from the solution of the heat conductivity and heat balance equations for the sensor head, based on the temperature difference between the base of the membrane 2 at the point of installation of the sensor 4 and the central part of the cap was minimal and amounted to about 1-2 G / C.

On the surface of the cap 6 from the side opposite to the membrane 2, a heat-reflecting coating, for example, of gold, nickel,

In the cap 6, a heat-insulating liner 8 is installed, on the outer surface of which, facing the membrane 2, there is a thin heat-reflecting layer 9, made in the form of a deposited layer of gold, nickel. The heat-insulating contribution 8 can be composite,

In the assembly of parts 7-9, a system of holes 10-12 is designed to output the connecting conductors from the temperature measurement sensors 3-5.

To ensure the reliability of the sensor, the conductors from temperature sensors 3-5 are mechanically connected to a plug-in 8, for example, heat-resistant cement. However, this should be ensured hydraulic connection of the bands

25

with

ten

15

; 35

40

45 -

This is located under the membrane 2 with the internal cavity of the sleeve 1. In the lower part of the sleeve there is a thermal insulating rod 13 through which the conductors from the temperature measurement sensors 3-5 are outputted.

The sleeve 1 can be connected to the structural elements (i.e., shown) of the object of research and is equipped with a cooling or heating system.

The sensor works as follows.

The heat flux acts on the outer surface of the membrane 2 and flows through the membrane 2 to the sleeve 1, through which it is removed, for example, to the cooling system.

At the same time, heat through side surface 7 enters cap 6 and heats it to a temperature close to the temperature of the inner surface of membrane 2. place temperature zone. Similarly, the heating and the outer surface of the liner 8,

The sensor allows minimizing heat loss from the inside of the membrane and ensuring an organized heat dissipation through the membrane to the sleeve.

The proposed heat flow sensor allows measurements to be made with an accuracy of 2-3%,

Claims (1)

Invention Formula A heat flow sensor comprising a heat conducting membrane mounted on the end of the heat conducting sleeve, a temperature difference sensor between the center of the membrane and the junction of the membrane with the sleeve, located on the inner side of the membrane, characterized in that, in order to improve accuracy by reducing heat loss , on the inner wall of the sleeve under the membrane with a gap is fixed a cap of heat-conducting material, made in the form of a glass, with an insert made of heat-insulating material installed on it from the side of the membrane .