CN103440381A - Thermal compensation design method for high-temperature air pipeline - Google Patents

Abstract

Provided is a thermal compensation design method for a high-temperature air pipeline. The thermal compensation design method includes the steps of using UG NX commercial software under a mechanical pipeline layout module to build a pipeline geometric model containing seven types of mathematical variables, carrying out pre-processing through finite element analysis software ANSYS, material parameters are given according to GH536, wherein an elasticity modulus E is equal to 187 GPa, and poisson ratio mu is equal to 0.3, utilizing boundary conditions and imposed displacement boundary conditions and temperature field load, calculating and obtaining the stress conditions of the pipeline, adjusting pipeline layout paths, carrying out calculation again according to the second content to the fourth content, and obtaining a new calculation result, that is, the maximum stress value is smaller than yield limit of materials, and yield strength reserve factor is larger than 1.5, and therefore the design requirements are met. The thermal compensation design method has the advantages of improving design reasonability and ensuring that the high-temperature air pipeline meets the requirements of engines for long service life and high reliability.

Description

A kind of compensation design method of high temperature air pipeline

Technical field

The present invention relates to aeromotor piping system design field, particularly a kind of compensation design method of high temperature air pipeline.

Background technology

Fault statistics data from home and abroad aircraft and aeromotor, because exterior line lost efficacy and the annex problem causes fault accounts for greatly the over half of total failare, be in first of structure failure, the Reliable Design of visible exterior line is most important to flight safety.

The extraneous air pipeline in engine high-temperature district, bearing at work aerodynamic loading, the alterante stress combined action that bearing temperature changes and engine luggine causes again, condition of work very severe, very easily, because of the deformation of pipeline and casing, produce fatigure failure.The pipeline caused due to temperature variation and casing linear expansion rigidly fixes the thermal stress at place, and the stress that can improve pipeline self is concentrated and reduced the pipeline fatigue limit.And the margin of safety coefficient of pipeline is directly proportional to its fatigue limit, the reduction of fatigue limit, must cause the decline of margin of safety coefficient, thereby have influence on functional reliability and the life-span of pipeline.

At present, aeromotor high temperature air pipeline traditional design method, mainly take experience as main, on version, with reference to external ripe pipeline structure form, lacks the method for designing of high temperature conduit and the appraisal procedure of the thermal deformation coordination ability.This causes the pipeline of design two aspect problems to occur:

One, thermal compensation scarce capacity.Affect the life-span of pipeline, can't meet the request for utilization of engine, even affected the safety of engine;

Two, thermal compensation ability surplus.The structural design that adopts pipeline self elastic deformation to carry out thermal compensation, the compensation ability surplus can cause pipeline to increase unnecessary weight, takes up room excessive, the layout of other annex and pipeline, cable around impact; In conduit, the medium flow resistance loss also can correspondingly increase simultaneously, and engine performance is exerted an influence.

At present, not yet someone proposed to adopt pipeline self elastic deformation to carry out the method for designing of thermal compensation.

Summary of the invention

The objective of the invention is to reduce the stress level of aeromotor high temperature air pipeline, the spy provides a kind of compensation design method of high temperature air pipeline.

The invention provides a kind of compensation design method of high temperature air pipeline, it is characterized in that: the compensation design method of described high temperature air pipeline, use UG NX business software to arrange under module at its mechanical pipeline, set up a pipeline geometric model (see figure 1) that comprises 7 kinds of mathematical variables, save as * .prt formatted file; The definition of each mathematical variable is in Table 1;

Utilize the format conversion function of UG NX software to generate * .x_t formatted file;

Utilize finite element analysis software ANSYS to call * .x_t file, generate * .db formatted file;

Read * .db formatted file by finite element analysis software ANSYS, carry out pre-treatment, the material parameter provides by GH536, elastic modulus E=187GPa wherein, Poisson ratio μ=0.3, linear expansion coefficient is in Table 2, and then the listed boundary condition of employing table 3 applies displacement boundary conditions and temperature field load, calculate the stress situation of pipeline, in Table 4;

The linear expansion coefficient of table 2 material 0Cr18Ni9

θ/℃	20～100	20～200	20～300	20～400	20～500	20～600	20～700
								α/10 -6℃ -1	12.1	12.5	13.4	14.0	14.3	14.8	15.5

Table 3 boundary condition

Table 4 pipeline stress value and yield strength reserve factor

As shown in Table 4, the maximum stress of pipeline has surpassed the yield limit of material, and the layout in this kind of pipeline path does not meet the demands; Therefore, need to be adjusted each mathematical variable; In the situation that pipeline starting point, final position and conduit diameter are definite, need be adjusted following variable:

---the crooked quantity of conduit, K value

---guiding-tube bend angle, A value

---the length of straigh line between adjacent two bent angles, L value;

After having adjusted the line arrangement path, by 2～4 contents, again calculated, obtained new result of calculation, in Table 5;

Table 5 pipeline stress value and yield strength reserve factor

The pipeline maximum stress value is less than the yield limit of material, and the yield strength reserve factor is greater than 1.5, meets design requirement.

Advantage of the present invention:

The compensation design method of high temperature air pipeline of the present invention, design high temperature air pipeline, improve the rationality of design, guarantees that the high temperature air pipeline meets engine long life-span and high reliability.

The accompanying drawing explanation

Below in conjunction with drawings and the embodiments, the present invention is further detailed explanation:

Fig. 1 is pipeline geometric model schematic diagram;

Fig. 2 is design flow diagram;

Fig. 3 is pipeline finite element model schematic diagram.

Embodiment

Embodiment 1

The invention provides a kind of compensation design method of high temperature air pipeline, it is characterized in that: the compensation design method of described high temperature air pipeline, use UG NX business software to arrange under module at its mechanical pipeline, set up a pipeline geometric model (see figure 1) that comprises 7 kinds of mathematical variables, save as * .prt formatted file; The definition of each mathematical variable is in Table 1;

Utilize the format conversion function of UG NX software to generate * .x_t formatted file;

Utilize finite element analysis software ANSYS to call * .x_t file, generate * .db formatted file;

Read * .db formatted file by finite element analysis software ANSYS, carry out pre-treatment, the material parameter provides by GH536, elastic modulus E=187GPa wherein, Poisson ratio μ=0.3, linear expansion coefficient is in Table 2, and then the listed boundary condition of employing table 3 applies displacement boundary conditions and temperature field load, calculate the stress situation of pipeline, in Table 4;

The linear expansion coefficient of table 2 material 0Cr18Ni9

θ/℃	20～100	20～200	20～300	20～400	20～500	20～600	20～700
								α/10 -6℃ -1	12.1	12.5	13.4	14.0	14.3	14.8	15.5

Table 3 boundary condition

Table 4 pipeline stress value and yield strength reserve factor

As shown in Table 4, the maximum stress of pipeline has surpassed the yield limit of material, and the layout in this kind of pipeline path does not meet the demands; Therefore, need to be adjusted each mathematical variable; In the situation that pipeline starting point, final position and conduit diameter are definite, need be adjusted following variable:

---the crooked quantity of conduit, K value

---guiding-tube bend angle, A value

---the length of straigh line between adjacent two bent angles, L value;

After having adjusted the line arrangement path, by 2～4 contents, again calculated, obtained new result of calculation, in Table 5;

Table 5 pipeline stress value and yield strength reserve factor

The pipeline maximum stress value is less than the yield limit of material, and the yield strength reserve factor is greater than 1.5, meets design requirement.

Claims (1)

1. the compensation design method of a high temperature air pipeline, it is characterized in that: the compensation design method of described high temperature air pipeline, use UG NX business software to arrange under module at its mechanical pipeline, set up a pipeline geometric model that comprises 7 kinds of mathematical variables, save as * .prt formatted file; The definition of each mathematical variable is in Table 1;

Utilize the format conversion function of UG NX software to generate * .x_t formatted file;

Utilize finite element analysis software ANSYS to call * .x_t file, generate * .db formatted file;

Read * .db formatted file by finite element analysis software ANSYS, carry out pre-treatment, the material parameter provides by GH536, elastic modulus E=187GPa wherein, Poisson ratio μ=0.3, linear expansion coefficient is in Table 2, and then the listed boundary condition of employing table 3 applies displacement boundary conditions and temperature field load, calculate the stress situation of pipeline, in Table 4;

The linear expansion coefficient of table 2 material 0Cr18Ni9

θ/℃ 20～100 20～200 20～300 20～400 20～500 20～600 20～700 α/10 ^-6℃ ^-1 12.1 12.5 13.4 14.0 14.3 14.8 15.5

Table 3 boundary condition

Table 4 pipeline stress value and yield strength reserve factor

As shown in Table 4, the maximum stress of pipeline has surpassed the yield limit of material, and the layout in this kind of pipeline path does not meet the demands; Therefore, need to be adjusted each mathematical variable; In the situation that pipeline starting point, final position and conduit diameter are definite, need be adjusted following variable:

---the crooked quantity of conduit, K value

---guiding-tube bend angle, A value

---the length of straigh line between adjacent two bent angles, L value;

After having adjusted the line arrangement path, by 2～4 contents, again calculated, obtained new result of calculation, in Table 5;

Table 5 pipeline stress value and yield strength reserve factor

The pipeline maximum stress value is less than the yield limit of material, and the yield strength reserve factor is greater than 1.5, meets design requirement.

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