CN-121997594-A - Measuring and calculating method for heat conductivity coefficient of insulating heat-conducting filler of adaptive cylindrical electric heating element

Abstract

The invention discloses a method for measuring and calculating the heat conductivity coefficient of an insulating heat-conducting filler of an adaptive cylindrical electric heating element, which comprises the following steps of constructing a simplified heat conduction model attached to the actual configuration of the cylindrical electric heating element, collecting and obtaining relevant parameters required by measurement, including structural parameters of the electric heating element, working parameters of the heating element and actual measurement temperature parameters of the outer wall of an electric heating element sleeve, substituting a calculation formula based on steady-state heat conduction of the cylindrical wall of the electric heating element into a calculation formula based on the relevant parameters to calculate the inner wall temperature of the electric heating element sleeve, calculating the heat conductivity coefficient of the insulating heat-conducting filler based on the steady-state heat conduction formula of the adaptive insulating heat-conducting filler filling structure, combining the collected relevant parameters of the heating element and the calculated inner wall temperature of the electric heating element sleeve, adapting various cylindrical electric heating elements without being limited by the type of the internal insulating heat-conducting filler, and having no need of destructive treatment on the electric heating element, thereby meeting the heat design requirements of the electric heating element in industrial scenes and having extremely high industrial practical value.

Inventors

• HAN LEI
• CAO CHONG
• XU SHIXUAN

Assignees

• 镇江东方电热有限公司

Dates

Publication Date

20260508

Application Date

20260126

Claims (6)

1. 1. The method for measuring and calculating the heat conductivity coefficient of the insulating heat-conducting filler of the adaptive cylindrical electric heating element is characterized by comprising the following steps of: S1, constructing an electric heating element structure, namely constructing a simplified heat conduction model which is attached to the actual configuration of the cylindrical electric heating element; S2, acquiring relevant parameters required by measurement and calculation, including structural parameters of the electric heating element, working parameters of the heating element and measured temperature parameters of the outer wall of the sleeve of the electric heating element, and providing complete data input for subsequent calculation; s3, calculating the temperature of the inner wall of the electric heating element sleeve, namely substituting the parameters acquired in the step S2 into a calculation formula of steady-state heat conduction of the cylinder wall of the electric heating element, and calculating to obtain the temperature of the inner wall of the electric heating element sleeve; s4, measuring and calculating the heat conductivity coefficient of the insulating heat conducting filler, namely, based on a steady-state heat conduction formula adapting to the filling structure of the insulating heat conducting filler, combining the heating element related parameters acquired in the step S2 and the temperature of the inner wall of the electric heating element sleeve obtained by calculation in the step S3, and measuring and calculating the heat conductivity coefficient of the insulating heat conducting filler.
2. 2. The method for measuring and calculating the heat conductivity coefficient of the insulating heat conducting filler of the adaptive cylindrical electric heating element according to claim 1, wherein in the step S1, the construction process of the simplified heat conduction model is as follows: The geometric boundaries of the heating element, the insulating heat-conducting filler layer and the electric heating element sleeve are constructed to be related to the structure, the heating element is simplified into a cylinder, the electric heating element sleeve is simplified into a cylindrical structure with an inner diameter, an outer diameter and a total length, and a filling area between the heating element and the electric heating element sleeve is the insulating heat-conducting filler layer with the heat conductivity coefficient to be calculated.
3. 3. The method for measuring and calculating the heat conductivity coefficient of the insulating heat-conducting filler of the adaptive cylindrical electric heating element according to claim 2, wherein in the step S2, the structural parameters of the electric heating element comprise the heat conductivity coefficient, the inner diameter, the outer diameter, the total length and the equivalent radius of the heating element of the electric heating element sleeve; the working parameters of the heating element comprise rated heating power and working temperature of the heating element.
4. 4. The method for measuring and calculating the heat conductivity coefficient of the insulating heat conducting filler of the adaptive cylindrical electric heating element according to claim 3, wherein in the step S3, the calculation formula of the steady-state heat conduction of the cylindrical wall is a calculation formula based on heat conduction of a metal sleeve, and the specific expression is shown in formula (1): (1); Wherein T 1 represents the temperature of the inner wall of the sleeve of the electric heating element; T 2 represents the measured temperature of the outer wall of the sleeve of the electric heating element; W represents rated heating power of the heating element; r 1 represents the inner diameter of the electric heating element sleeve; R 2 represents the outer diameter of the heating element sleeve; ln represents a natural logarithmic function; H represents the total length of the electric heating element sleeve; Indicating the thermal conductivity of the heating element sleeve.
5. 5. The method for measuring and calculating the heat conductivity coefficient of the insulating and heat conducting filler of the adaptive cylindrical electric heating element according to claim 4, wherein in the step S4, a specific expression of a steady-state heat conduction formula of the filling structure of the adaptive insulating and heat conducting filler is shown as a formula (2): (2); Wherein, the Representing the thermal conductivity of the insulating thermal conductive filler; Indicating the difference between the working temperature of the heating element and the temperature of the inner wall of the sleeve of the electric heating element; R 0 represents the equivalent radius of the heating element.
6. 6. The method for measuring and calculating the heat conductivity coefficient of the insulating heat conducting filler of the cylindrical electric heating element according to claim 5, wherein the calculation formula of the difference between the working temperature of the heating element and the temperature of the inner wall of the sleeve of the electric heating element is shown in formula (3): (3); Wherein T 0 represents the operating temperature of the heating element.

Description

Measuring and calculating method for heat conductivity coefficient of insulating heat-conducting filler of adaptive cylindrical electric heating element Technical Field The invention belongs to the technical field of electric heating element design, and particularly relates to a method for measuring and calculating the heat conductivity coefficient of an insulating heat-conducting filler of a cylindrical electric heating element. Background In extreme industrial scenes such as aerospace, ultrahigh temperature gas heating and the like, an electric heating element is used as a core energy conversion and transmission component, the performance of the electric heating element directly determines the operation reliability, energy efficiency level and extreme environmental adaptability of equipment, the electric heating element generally adopts an integrated packaging structure of a heating element, an insulating heat conducting filler and an electric heating element sleeve, wherein the insulating heat conducting filler is a heat transfer bridge and an insulating protection core, the heat conductivity coefficient of the insulating heat conducting filler directly influences the heat conversion efficiency, the temperature field uniformity and the heat response speed, and the electric heating element is a key parameter for guaranteeing the structural stability under extreme working conditions. The existing measuring and calculating method for the thermal conductivity coefficient of the insulating and heat conducting filler has the defects that 1, the traditional destructive test needs to disassemble and slice the electric heating element, so that an expensive test piece is scrapped, the test period is long (days to weeks), the research and development iteration of equipment is seriously delayed, 2, the purchase and maintenance cost of high-precision test equipment such as a laser flash instrument is high (millions of yuan), the popularity is extremely poor, the test needs to be carried out in an ideal laboratory environment, the test is disjointed with the complex working conditions such as high temperature, vibration and medium corrosion of the actual working of the electric heating element, the requirements on the shape and the size precision of a sample are strict, the non-uniformity and the irregular state of the filler in the actual application are difficult to be matched, and the reference value of test data is limited, and the measuring and calculating method for the thermal conductivity coefficient of the insulating and heat conducting filler of the adaptive cylindrical electric heating element is provided for the purposes. Disclosure of Invention The invention aims to provide a method for measuring and calculating the heat conductivity coefficient of an insulating heat-conducting filler of a cylindrical electric heating element, which is suitable for solving the problems in the background art. The technical scheme includes that the method comprises the following steps of S1, constructing an electric heating element structure, constructing a simplified heat conduction model attached to the actual configuration of the cylindrical electric heating element, S2, collecting electric heating element parameters, wherein the collecting and obtaining relevant parameters required by measurement, the relevant parameters comprise structural parameters of the electric heating element, working parameters of the electric heating element and measured temperature parameters of the outer wall of an electric heating element sleeve, providing complete data input for subsequent calculation, S3, calculating the inner wall temperature of the electric heating element sleeve, substituting the relevant parameters collected in the step S2 into a steady-state heat conduction calculation formula of the cylinder wall of the electric heating element, calculating to obtain the inner wall temperature of the electric heating element sleeve, S4, calculating the heat conductivity coefficient of the insulating heat conduction filler, and calculating the heat conductivity coefficient of the insulating heat conduction filler by combining the relevant parameters of the electric heating element collected in the step S2 and the inner wall temperature of the electric heating element sleeve calculated in the step S3. Preferably, in step S1, the simplified heat conduction model is constructed by constructing geometric boundaries and structures of a heating element, an insulating heat-conducting filler layer and an electric heating element sleeve, simplifying the heating element into a cylinder, simplifying the electric heating element sleeve into a cylindrical structure with an inner diameter, an outer diameter and a total length, and the filling area between the heating element and the electric heating element sleeve is the insulating heat-conducting filler layer with the heat conductivity coefficient to be calculated. Preferably, in step S2, the stru