CN-117505215-B - Local self-adaptive porous matrix combined with sublimation of coating and preparation method thereof

CN117505215BCN 117505215 BCN117505215 BCN 117505215BCN-117505215-B

Abstract

The invention discloses a preparation method of a local self-adaptive porous matrix combined with coating sublimation, which comprises the following steps of screening coating materials according to the safe temperature of the porous matrix, wherein the sublimation point temperature of the selected coating materials is less than or equal to the safe temperature-preset temperature of the porous matrix, mixing each coating material with auxiliary agents required in the spraying process to obtain a coating material mixture, carrying out thermogravimetric analysis on the coating material mixture, obtaining the weight loss and the residual quantity of each coating material mixture through experiments, selecting the coating material mixture with the weight loss ratio being more than or equal to 96% and the residual quantity being less than or equal to 4% under the condition of being higher than the sublimation point temperature of the coating material, and coating the coating material mixture on the heated side of the porous matrix to obtain the self-adaptive porous matrix.

Inventors

LI WENQIANG
ZHU PENGFEI
XUE ZHAORUI
QIN FEI
WEI XIANGGENG
HE GUOQIANG

Assignees

西北工业大学

Dates

Publication Date: 20260512
Application Date: 20231106
Priority Date: 20230831

Claims (10)

1. A method for preparing a locally adaptive porous matrix for sublimation of a bond coating, comprising the steps of: Step 1, screening coating materials according to the safe temperature of the porous matrix, wherein the sublimation point temperature of the selected coating materials is less than or equal to the safe temperature-preset temperature of the porous matrix, Step 2, mixing each coating material with the auxiliary agent required in the spraying process to obtain a coating material mixture, carrying out thermogravimetric analysis on the coating material mixture, obtaining the weight loss and the residual quantity of each coating material mixture through experiments, Step 3, selecting a coating material mixture with the loss weight ratio more than or equal to 96% and the residual quantity less than or equal to 4% under the condition of being higher than the sublimation point temperature of the coating material, coating the coating material mixture on the heated side of the porous matrix to obtain a self-adaptive porous matrix, The porous matrix is characterized in that the heated side surface of the porous matrix is divided into an exposed area and a coating area, the coating area is coated with a coating material mixture and is used for completely closing pores except the exposed area on the porous matrix during sweating and cooling so as to prevent leakage of the coolant, and the exposed area is the heated side surface of the exposed porous matrix and is used for guiding the coolant and intensively exuding from the exposed area.
2. A method of preparing a locally adaptive porous matrix incorporating sublimation of a coating according to claim 1, wherein in step 1 two coating materials are selected, a first coating material and a second coating material, respectively, the first coating material having a predetermined temperature of 201-400 ℃ and the second coating material having a predetermined temperature of 100-200 ℃; the first coating material is mixed with an auxiliary agent required in the spraying process to obtain a first coating mixture, and the second coating material is mixed with the auxiliary agent required in the spraying process to obtain a second coating mixture; The coating area is divided into a first coating area and a second coating area, the first coating area is close to the exposed area and extends outwards in an annular shape by taking the exposed area as a center, and the second coating area is far away from the exposed area and extends outwards in an annular shape by taking the exposed area as a center and is contacted with the first coating area; The first coating mixture is coated in a first coating area, the second coating mixture is coated in a second coating area, and the coating thickness of the first coating mixture is smaller than that of the second coating mixture.
3. A method of preparing a locally adaptive porous matrix incorporating sublimation of a coating according to claim 1, wherein in step 1a coating material is selected, the predetermined temperature of the material being 201-400 ℃, the thickness of the coating in the coating zone being 50-200 μm.
4. A method of preparing a locally adaptive porous matrix incorporating sublimation of a coating according to claim 3, wherein the coating zone is divided into a first coating zone and a second coating zone, the first coating zone being adjacent to and extending outwardly in an annular shape centered on the exposed zone, the second coating zone being remote from and extending outwardly in an annular shape centered on the exposed zone and contacting the first coating zone, the first coating zone having a coating thickness less than the coating thickness of the second coating zone.
5. A method of preparing a locally adaptive porous matrix incorporating sublimation of a coating according to claim 1, wherein the coating region is disposed around an exposed region, and the exposed region is circular or square.
6. The method for preparing a locally adaptive porous matrix for sublimation of a bonding coating according to claim 1, wherein the porous matrix is a stainless steel porous plate, a nickel-based alloy porous plate or a C/SiC composite porous plate, the safety temperature of the nickel-based alloy porous plate is 1000 ℃, the safety temperature of the C/SiC composite porous plate is 1650 ℃, the safety temperature of the stainless steel porous plate is 600 ℃, the porosity of the porous matrix is 10% -40%, and the porosity of the porous matrix is 5-100 μm.
7. A method of preparing a locally adaptive porous matrix incorporating sublimation of a coating according to claim 1, wherein the method of coating the coating area in step 3 is: Cleaning the porous matrix to remove impurities, drying, Labeling paper is stuck on the surface of the heated side of the porous matrix at the position corresponding to the exposed area, And repeatedly and uniformly coating the coating material mixture on the surface of the heated side of the porous matrix, removing the label paper and standing.
8. A method of preparing a locally adaptive porous matrix incorporating sublimation of a coating according to claim 2 or 4, wherein the method of coating the coating zone in step 3 is: Cleaning the porous matrix to remove impurities, drying, A label paper is attached to the surface of the heated side of the porous matrix at the position corresponding to the exposed area and the first coating area, Repeatedly and uniformly coating the second coating mixture on the surface of the heated side of the porous matrix, removing the label paper and standing, Labeling paper on the surface of the heated side of the porous matrix at the position corresponding to the exposed area and the second coating area, And repeatedly and uniformly coating the first coating mixture on the surface of the heated side of the porous matrix, removing the label paper and standing.
9. A locally adaptive porous matrix combining coating sublimation, prepared according to the preparation method of claim 1, characterized in that the coating zone is divided into a first coating zone and a second coating zone, wherein the first coating zone is close to the bare zone and extends outwards in an annular shape with the bare zone as the center, the second coating zone is far from the bare zone and extends outwards in an annular shape with the bare zone as the center and contacts the first coating zone, An adaptive coating layer coated on the first coating area and the second coating area of the porous matrix, wherein the coating thickness of the first coating area is smaller than that of the second coating area, Wherein the coating material mixture of the first coating region and the second coating region is the same.
10. A locally adaptive porous matrix combining coating sublimation, prepared according to the preparation method of claim 1, characterized in that the coating zone is divided into a first coating zone and a second coating zone, wherein the first coating zone is close to the bare zone and extends outwards in an annular shape with the bare zone as the center, the second coating zone is far from the bare zone and extends outwards in an annular shape with the bare zone as the center and contacts the first coating zone, A first adaptive coating applied to a first coating region of the porous substrate, A second adaptive coating applied to a second coating region of the porous substrate, Wherein the coating material mixture of the first adaptive coating and the second adaptive coating is different, and the coating thickness of the first coating area is smaller than the coating thickness of the second coating area.

Description

Local self-adaptive porous matrix combined with sublimation of coating and preparation method thereof Technical Field The invention belongs to the field of heat transfer and flow, and particularly relates to a local self-adaptive porous matrix combined with coating sublimation and a preparation method thereof. Background The sweating cooling technology can be regarded as a bionic technology, and the technology reduces the surface temperature in a high-temperature environment through sweating so as to achieve the aim of heat protection. In the sweating cooling process, the cooling fluid firstly flows through the porous wall surface and carries out strong convection heat exchange to take away heat, and then a layer of compact liquid film or air film is formed on the surface of the wall surface so as to reduce the heat transfer of the high-temperature main flow to the wall surface. However, in many high temperature environments, the heat flux density distribution of the heated surface is typically non-uniform. In the local overheating area, the cooling liquid evaporates into a gaseous state, the flow resistance of the fluid is increased, the steam blocking effect is caused, the cooling liquid avoids the overheating steam area in the porous material and seeps out from other channels with smaller flow resistance, the temperature of the local overheating area is higher, the cooling efficiency is lower, even the local porous structure is higher Wen Resun, meanwhile, the temperature of the heated surface is unevenly distributed, the flow rate of the cooling medium in the local high-temperature area is lower, the cooling medium preferentially flows out from the area with smaller surface heat load, the hot side surface cannot be reasonably distributed correspondingly, the phenomenon of local overheating can be weakened by increasing the supply flow rate of the cooling medium, but the waste of the cooling medium is also easily caused, and the negative quality of application equipment is increased. A series of problems caused by the steam blocking effect can be overcome by changing the distribution of physical parameters such as the thickness, the porosity, the pore diameter and the like of the porous matrix, but the process is complex and difficult, and under the condition that the distribution of the heat flow density is complex or unclear, the design and manufacture of the sweating cooling structure which can adapt to the distribution of the heat flow density are difficult. These drawbacks have prevented the application of sweat cooling in ultra-high sound speed new space vehicles. Disclosure of Invention The invention aims to provide a preparation method of a local self-adaptive porous matrix combined with sublimation of a coating, which aims to solve the problems of local overheating, uneven temperature distribution of a heated surface and difficult adaptation of sweating cooling to complicated or unclear heat flux density distribution in the existing porous sweating cooling. The invention adopts the following technical scheme that the preparation method of the local self-adaptive porous matrix combined with the sublimation of the coating comprises the following steps: Step 1, screening coating materials according to the safe temperature of the porous matrix, wherein the sublimation point temperature of the selected coating materials is less than or equal to the safe temperature-preset temperature of the porous matrix, Step 2, mixing each coating material with the auxiliary agent required in the spraying process to obtain a coating material mixture, carrying out thermogravimetric analysis on the coating material mixture, obtaining the weight loss and the residual quantity of each coating material mixture through experiments, Step 3, selecting a coating material mixture with the loss weight ratio more than or equal to 96% and the residual quantity less than or equal to 4% under the condition of being higher than the sublimation point temperature of the coating material, coating the coating material mixture on the heated side of the porous matrix to obtain a self-adaptive porous matrix, The heated side surface of the porous matrix is divided into an exposed area and a coating area, the coating area is coated with a coating material mixture and is used for completely closing pores except the exposed area on the porous matrix when the porous matrix is subjected to sweat cooling so as to prevent leakage of the coolant, and the exposed area is the heated side surface of the exposed porous matrix and is used for guiding the coolant and intensively exuding from the exposed area. Further, in step 1, two coating materials may be selected, wherein the two coating materials are a first coating material and a second coating material, respectively, the predetermined temperature of the first coating material is 201-400 ℃, and the predetermined temperature of the second coating material is 100-200 ℃; the first coating material is