Pipeline surface frosting analysis test system and method based on wind tunnel

Abstract

The invention relates to a wind tunnel-based pipeline surface frosting analysis test system and method, relates to the technical field of wind tunnel tests, and aims to research the surface frosting phenomenon of a pipeline and obtain the characteristics of the pipeline surface frosting rate. According to the scheme, the first view field rectangle and the second view field rectangle of the outer surface of the internally tangent pipeline can be obtained in real time based on the first image collecting device, the second image collecting device, the third image collecting device and the fourth image collecting device; and obtaining an octagon of which each edge is tangent to the outer surface of the pipeline based on the first field-of-view rectangle and the second field-of-view rectangle, calculating the length of each edge in the octagon, and calculating the sectional area and volume of the pipeline based on the length of each edge in the octagon so as to meet the analysis requirement of frost on the surface of the pipeline. On the basis, the surface frosting phenomenon of the pipeline can be researched, and the surface frosting rate of the pipeline can be obtained.

Description

Technical Field

[0001] This invention relates to the field of wind tunnel testing technology, specifically to a wind tunnel-based test system and method for analyzing frost formation on pipe surfaces. Background Technology

[0002] Intensive precooling technology is one of the key approaches to overcoming the thrust gap in turbojet-powered combined-engine aircraft. As the primary method for implementing intensive precooling, precoolers are typically designed as lightweight, efficient, and compact heat exchange devices. Among these, the microtube precooler has proven to be an effective structural form and has been successfully applied to the Sabre engine, extending the operating range of the air-breathing engine to Mach 5. This type of precooler typically circulates cryogenic liquid helium or liquid hydrogen, causing the surface temperature of the microtube heat exchanger to drop to a cryogenic state below -100 degrees Celsius. Under these conditions, if the incoming air contains moisture, frost will form on the surface of the heat exchanger tubes.

[0003] Research on the frosting phenomenon and mechanism on the surface of the micro-channels of the precooler can provide basic data support for the research on anti-frost technology of the precooler. Summary of the Invention

[0004] The technical problem to be solved by this application is to provide a wind tunnel-based pipe surface frost analysis test system and method, which has the characteristics of studying the frost phenomenon on the pipe surface and obtaining the frost rate on the pipe surface.

[0005] In one aspect, one embodiment provides a wind tunnel-based pipe surface frost analysis test system, including an image acquisition subsystem, a temperature control subsystem, and a humid air inflow control subsystem; The pipe is vertically installed in the wind tunnel test section. The temperature control subsystem is used to control the temperature of the wind tunnel test section. The humid air inflow control subsystem is used to control the inflow of humid air onto the pipe surface so that frost forms on the pipe surface under the influence of temperature. The image acquisition subsystem includes a reflector installed inside the wind tunnel test section and multiple image acquisition devices installed on both sides outside the wind tunnel test section. The reflector is positioned on the opposite side of the airflow direction of the pipe, and the multiple image acquisition devices are used to acquire surface images of the pipe, including: The first image acquisition device has its visual direction perpendicular to the direction of the incoming flow of humid air. The second image acquisition device has a visual direction parallel to that of the first image acquisition device, and obtains an image of the opposite side of the airflow direction of the pipe through a reflector. The visual directions of both the third and fourth image acquisition devices are at an acute angle to the direction of the incoming humid air flow, and the visual direction of the third image acquisition device is perpendicular to the visual direction of the fourth image acquisition device.

[0006] Secondly, in one embodiment, a method for analyzing pipe surface frost based on a wind tunnel is provided, implemented based on the aforementioned pipe surface frost analysis system. The method includes: Based on the first image acquisition device and the second image acquisition device, a first field of view rectangle is obtained in real time, and the outer surface of the pipe is inscribed in the first field of view rectangle; Based on the third and fourth image acquisition devices, a second field of view rectangle is obtained in real time, and the outer surface of the pipe is inscribed in the second field of view rectangle. Based on the first field-of-view rectangle and the second field-of-view rectangle, obtain an octagon in which each side is tangent to the outer surface of the pipe, and calculate the length of each side in the octagon. Calculate the cross-sectional area and volume of the pipe based on the length of each side of the octagon.

[0007] The beneficial effects of this invention are: A wind tunnel-based pipe surface frost analysis test system and method can obtain the length of each side of an octagon obtained from two field-of-view rectangles by multiple image acquisition devices, thereby obtaining the cross-sectional area and volume of the pipe. This allows for the acquisition of increments of various parameters over a preset time period to meet the needs of pipe surface frost analysis. Based on this, the frost phenomenon on the pipe surface can be studied, and the frost rate of the pipe surface can be obtained. Attached Figure Description

[0008] Figure 1 This is a top view schematic diagram of a wind tunnel test section according to an embodiment of this application; Figure 2 This is a top view of another embodiment of the wind tunnel test section of this application; Figure 3 This is a schematic diagram of an embodiment of the present application that obtains an octagonal shape on the pipe surface based on a first field-of-view matrix and a second field-of-view matrix; Figure 4 This is a schematic diagram of a wind tunnel-based pipeline surface frost analysis test method according to one embodiment of this application.

[0009] In the diagram, 01 is the first image acquisition device, 02 is the second image acquisition device, 03 is the third image acquisition device, 04 is the fourth image acquisition device, 05 is the pipe, 06 is the reflector, 07 is the first light source, and 08 is the second light source. Detailed Implementation

[0010] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Similar elements in different embodiments are referred to by related similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the present application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to the present application are not shown or described in the specification. This is to avoid obscuring the core parts of the present application with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0011] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can be rearranged or adjusted in a manner obvious to those skilled in the art. Therefore, the various orders in the specification and drawings are only for the clear description of a particular embodiment and do not imply a necessary order, unless otherwise stated that a particular order must be followed.

[0012] The serial numbers assigned to components in this article, such as "first" and "second", are used only to distinguish the objects being described and have no sequential or technical meaning.

[0013] In view of the problems encountered in the prior art, this application provides a wind tunnel-based pipe surface frost analysis test system and method, which is used to measure the three-dimensional axisymmetric frost profile and process the data during the experimental study of frost formation on the surface of micro-pipes (low-temperature circular heat exchange pipes) of precoolers. Through the solution of this application, the changes of the frost layer on the pipe surface can be obtained in real time during the pipe frost formation process, so as to further analyze the influence of the frost layer on the heat exchange and flow of the precooler.

[0014] The following section introduces the wind tunnel-based test system for analyzing frost formation on pipe surfaces.

[0015] This application provides a wind tunnel-based pipe surface frost analysis test system, including an image acquisition subsystem, a temperature control subsystem, and a humid air inflow control subsystem.

[0016] Please refer to Figure 1 and Figure 2 All of these are top-view schematic diagrams based on the wind tunnel test section. The system in this application includes an image acquisition subsystem, a temperature control subsystem, and a humid air inflow control subsystem.

[0017] Pipe 05 is vertically installed within the wind tunnel test section. A temperature control subsystem controls the temperature of the wind tunnel test section, while a humid air inflow control subsystem controls the inflow of humid air onto the surface of pipe 05, causing frost to form on its surface under the influence of temperature. In this way, the wind tunnel test section can provide an inflow of humid air with adjustable moisture content, velocity, and temperature.

[0018] Glass observation windows are installed on both side walls of the wind tunnel test section. The image acquisition subsystem includes a reflector 06 installed inside the wind tunnel test section and multiple image acquisition devices installed on both sides outside the wind tunnel test section (outside the glass observation windows). The reflector 06 is positioned on the opposite side of the airflow direction of the duct 05, and the multiple image acquisition devices are used to acquire surface images of the duct 05. The multiple image acquisition devices include a first image acquisition device 01, a second image acquisition device 02, a third image acquisition device 03, and a fourth image acquisition device 04. The visual direction of the first image acquisition device 01 is perpendicular to the direction of the humid airflow; the visual direction of the second image acquisition device 02 is parallel to the visual direction of the first image acquisition device, and it obtains the image of the opposite side of the airflow direction of the duct 05 through the reflector 06; the visual directions of the third image acquisition device 03 and the fourth image acquisition device 04 are both at an acute angle to the direction of the humid airflow, and the visual direction of the third image acquisition device is perpendicular to the visual direction of the fourth image acquisition device.

[0019] The second image acquisition device 02 and the first image acquisition device 01 can be located on the same side outside the wind tunnel or on opposite sides outside the wind tunnel, both of which are within the protection scope of this application.

[0020] In one embodiment, for ease of calculation and analysis, the direction of the incoming humid air flow is parallel to the window side of the wind tunnel test section, and the visual direction of the first image acquisition device 01 and the second image acquisition device 02 is perpendicular to the window of the wind tunnel test section; the visual direction of the third image acquisition device 03 and the fourth image acquisition device 04 is tilted to the window of the wind tunnel test section.

[0021] The applicant discovered during research that if the positions of the aforementioned image acquisition devices are not precisely set, it is difficult to obtain high-quality images. Therefore, this application provides a method for determining the specific positions of each image acquisition device, so as to set the image acquisition devices based on the determined positions. Please refer to... Figure 2 The method for determining the location may include: first, obtaining the focal length and magnification of each image acquisition device.

[0022] The applicant also discovered in the research that for any image acquisition device, if its visual direction is not perpendicular to the viewing window glass, the refraction of the glass will cause a deviation between the distance calculated directly based on the focal length and magnification and the nearest light distance, thus affecting the image quality.

[0023] Therefore, for any image acquisition device, if its visual direction is not perpendicular to the viewing window glass, the refraction effect of the glass must be considered to obtain the nearest physical location distance. If its visual direction is perpendicular to the viewing window glass, the influence of the glass refraction effect can be ignored.

[0024] As an embodiment of this application, since the visual direction of the first image acquisition device 01 is perpendicular to the window glass, the closest physical position distance between the lens of the first image acquisition device and the surface of the pipe 05 is calculated based on its focal length and magnification as the closest physical position distance, and the location of the first image acquisition device is determined based on this closest physical position distance.

[0025] The nearest physical distance between the lens of the first image acquisition device 01 and the surface of the pipe 05, calculated based on the focal length and magnification of the first image acquisition device 01, can be expressed as: in, This indicates the focal length of the first image acquisition device 01. Indicates the magnification of the first image acquisition device. This indicates the closest physical distance between the lens of the first image acquisition device 01 and the surface of the pipe 05.

[0026] As one embodiment of this application, since the visual direction of the second image acquisition device 02 is perpendicular to the window glass, the location of the second image acquisition device 02 is determined by the sum of the physical distance between the lens of the second image acquisition device 02 and the physical distance between the mirror 06 and the nearest physical distance between the mirror 06 and the surface of the pipe 05, based on the position of the mirror 06 and the focal length and magnification of the second image acquisition device 02.

[0027] The sum of the distances to the nearest physical locations mentioned above can be expressed as: in, This indicates the focal length of the second image acquisition device 02. This indicates the magnification of the second image acquisition device 02. This represents the sum of the physical distance between the lens of the second image acquisition device 02 and the reflector 06, and the nearest physical distance between the reflector 06 and the surface of the pipe 05. This indicates the physical distance between the lens of the second image acquisition device 02 and the reflector 06. This indicates the nearest physical distance between the reflector 06 and the surface of the pipe 05.

[0028] Based on the sum of the nearest physical location distances, the position of reflector 06 can be determined first, and then based on... Sure Alternatively, the position of the second image acquisition device 02 can be determined first, and then based on... Sure .

[0029] As an embodiment of this application, since the visual directions of the third image acquisition device 03 and the fourth image acquisition device 04 are not perpendicular to the viewing window glass, the nearest light distance between the lens of the third image acquisition device 03 and the fourth image acquisition device 04 and the surface of the pipe 05 is calculated based on their respective focal length and magnification. Based on their respective nearest light distance, the angle between their lenses and the normal of the viewing window glass and the refractive index of the viewing window glass, the nearest physical position distance between their lenses and the surface of the pipe 05 is calculated, thereby determining the location of the third image acquisition device 03 and the fourth image acquisition device 04.

[0030] In one embodiment, the third image acquisition device 03 and the fourth image acquisition device 04 calculate the nearest ray distance between their respective lenses and the surface of the pipe 05 based on their respective focal lengths and magnifications. Based on their respective nearest ray distances, the angle between their lenses and the normal to the viewing window glass, and the refractive index of the viewing window glass, they calculate the nearest physical distance between their respective lenses and the surface of the pipe 05. This can be expressed as: in, and These represent the focal length and magnification of the third image acquisition device 03, respectively. and These represent the focal length and magnification of the fourth image acquisition device 04, respectively. and represents the angles between the visual direction of the third image acquisition device 03 and the normal to the viewing window glass, respectively, and h represents the thickness of the viewing window glass. Indicates the refractive index of the viewing window glass. and They represent and The angle of refraction in the viewing window glass, and These represent the closest light distances between the lenses of the third image acquisition device 03 and the fourth image acquisition device 04 and the surface of the pipe 05, respectively. and These represent the closest physical distances between the lenses of the third image acquisition device 03 and the fourth image acquisition device 04 and the surface of the pipe 05, respectively.

[0031] As one embodiment of this application, the system further includes a lighting subsystem for providing illumination to the test environment of the test section. In one embodiment, please refer to... Figure 1 The lighting subsystem includes a first light source 07 and a second light source 08 located outside the viewing windows on both sides.

[0032] For the wind tunnel-based pipe surface frosting analysis test system based on the above embodiments, please refer to... Figure 3 Based on the first image acquisition device 01 and the second image acquisition device 02, the side lengths of two adjacent sides of the first field of view rectangle formed by the two image acquisition devices on the surface of the pipe 05 (or the frosted surface if frost forms during image acquisition) can be obtained. and Based on the third image acquisition device 03 and the fourth image acquisition device 04, the side lengths of two adjacent sides of the second field of view rectangle formed by the two image acquisition devices on the surface of the pipe 05 can be obtained. and Based on this, the frosting condition on the surface of pipe 05 can be analyzed.

[0033] The following describes the test method for analyzing frost formation on pipe surfaces based on wind tunnel conditions.

[0034] This application provides a wind tunnel-based method for analyzing frost formation on pipe surfaces. This method is implemented based on the pipe surface frost analysis system described in any of the above embodiments. Please refer to [link / reference]. Figure 3 and Figure 4 ,include: Step S10: Based on the first image acquisition device and the second image acquisition device, a first field of view rectangle is obtained in real time, and the outer surface of the pipe is inscribed in the first field of view rectangle.

[0035] Please refer to Figure 3 In the side length of the first field-of-view rectangle, Obtained based on the field of view of the first image acquisition device. The field of view is obtained based on the second image acquisition device.

[0036] Those skilled in the art will understand that, with the deposition of frost, and It changes over time; therefore, in frosting analysis, the first field of view rectangle needs to be obtained in real time.

[0037] Step S20: Based on the third image acquisition device and the fourth image acquisition device, the second field of view rectangle is obtained in real time, and the outer surface of the pipe is inscribed in the second field of view rectangle.

[0038] Please refer to Figure 3 In the side length of the second field-of-view rectangle, Obtained based on the field of view of the third image acquisition device. The field of view is obtained based on the fourth image acquisition device.

[0039] Those skilled in the art will understand that, with the deposition of frost, and It changes over time; therefore, in frosting analysis, the second field of view rectangle needs to be acquired in real time.

[0040] Step S30: Based on the first field of view rectangle and the second field of view rectangle, obtain an octagon whose sides are tangent to the outer surface of the pipe, and calculate the length of each side of the octagon.

[0041] In one embodiment of this application, since the direction of the incoming humid air flow is parallel to the window side of the wind tunnel test section, the visual directions of the first and second image acquisition devices are perpendicular to the window of the wind tunnel test section; the visual directions of the third and fourth image acquisition devices are tilted to the window of the wind tunnel test section; therefore: We can obtain: in, and These represent the angles between the visual direction of the third and fourth image acquisition devices and the normal to the viewing window glass, respectively. and These represent the side lengths corresponding to the fields of view of the first image acquisition device and the second image acquisition device within the first field of view rectangle, respectively. and These represent the side lengths corresponding to the fields of view of the third and fourth image acquisition devices within the second field of view rectangle, respectively. This represents the side length corresponding to the field of view of the first image acquisition device in the octagon. In octagon The length of the opposite side, This represents the side length corresponding to the field of view of the second image acquisition device in the octagon. In octagon The length of the opposite side, This represents the side length corresponding to the field of view of the third image acquisition device in the octagon. In octagon The length of the opposite side, This represents the side length corresponding to the field of view of the fourth image acquisition device in the octagon. In octagon The length of the opposite side.

[0042] Therefore, the length of each side of the octagon can be calculated based on the matrix described above.

[0043] Step S40: Calculate the cross-sectional area and volume of the pipe based on the length of each side of the octagon.

[0044] Since the cross-sectional area of ​​the pipe can be expressed as the first field-of-view rectangle minus the area of ​​the four corners, in one embodiment, step S40 can be expressed as: in, This indicates the cross-sectional area of ​​the pipe. , , and All are intermediate quantities. Indicates the volume of the pipe. Indicates the length of the pipe.

[0045] Based on the above process, various parameters can be obtained, including the length of any one or more sides of the octagon, the cross-sectional area of ​​the pipe, and the volume of the pipe, to meet the analysis needs of frost accumulation on the pipe surface.

[0046] In one embodiment, the pipe surface frost analysis test method of this application embodiment may further include: calculating the increment of any one or more of a variety of parameters within a preset time length, wherein the aforementioned multiple parameters include: the length of any one or more sides of the octagon, the cross-sectional area of ​​the pipe, and the volume of the pipe.

[0047] Based on the wind tunnel-based pipe surface frost analysis test system and method provided in this application, the length of each side of the octagon obtained by two field-of-view rectangles can be acquired by multiple image acquisition devices, thereby obtaining the cross-sectional area and volume of the pipe. This allows for the acquisition of increments of various parameters for a preset time length to meet the needs of pipe surface frost analysis. Based on this, the frost phenomenon on the pipe surface can be studied, and the frost rate on the pipe surface can be obtained.

[0048] One embodiment of this application provides a computer-readable storage medium storing a program, the stored program including methods that can be loaded by a processor and processed in any of the above embodiments.

[0049] Those skilled in the art will understand that all or part of the functions of the various methods in the above embodiments can be implemented by hardware or by computer programs. When all or part of the functions in the above embodiments are implemented by computer programs, the program can be stored in a computer-readable storage medium, which may include: read-only memory, random access memory, disk, optical disk, hard disk, etc., and the program is executed by a computer to achieve the above functions. For example, the program can be stored in the memory of a device, and when the program in the memory is executed by the processor, all or part of the above functions can be achieved. In addition, when all or part of the functions in the above embodiments are implemented by computer programs, the program can also be stored in a server, another computer, disk, optical disk, flash drive, or external hard drive, etc., and can be downloaded or copied to the memory of a local device, or the system of the local device can be updated. When the program in the memory is executed by the processor, all or part of the functions in the above embodiments can be achieved.

[0050] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A wind tunnel based pipe surface frost analysis test system, characterized by, The system comprises an image acquisition subsystem, a temperature control subsystem and a wet air flow control subsystem; The temperature control subsystem is used to control the temperature of the wind tunnel test section, and the wet air flow control subsystem is used to control the wet air flow on the surface of the pipe to form frost on the surface of the pipe under the action of temperature. The image acquisition subsystem comprises a mirror arranged in the wind tunnel test section and a plurality of image acquisition devices arranged on both sides of the wind tunnel test section, the mirror is arranged on the opposite side of the air flow direction side of the pipe, and the plurality of image acquisition devices are used to acquire the surface image of the pipe, comprising: The first image acquisition device has a visual direction perpendicular to the wet air flow direction; The second image acquisition device has a visual direction parallel to the visual direction of the first image acquisition device and obtains the image of the opposite side of the air flow direction side of the pipe through the mirror; The third image acquisition device and the fourth image acquisition device have visual directions forming acute angles with the wet air flow direction, and the visual direction of the third image acquisition device is perpendicular to the visual direction of the fourth image acquisition device.

2. The pipe surface frost analysis test system of claim 1, wherein, The system further comprises an illumination subsystem for providing illumination for the test environment of the test section.

3. The pipe surface frost analysis test system of claim 1, wherein, The second image acquisition device and the first image acquisition device are arranged on the same side or opposite side of the wind tunnel.

4. The pipe surface frost analysis test system of claim 1, wherein, The wet air flow direction is parallel to the window side of the wind tunnel test section, the visual directions of the first image acquisition device and the second image acquisition device are perpendicular to the window of the wind tunnel test section, and the visual directions of the third image acquisition device and the fourth image acquisition device are inclined to the window of the wind tunnel test section.

5. The pipe surface frost analysis test system of claim 1, wherein, The positions of the first image acquisition device, the second image acquisition device, the third image acquisition device and the fourth image acquisition device are determined, and the first image acquisition device, the second image acquisition device, the third image acquisition device and the fourth image acquisition device are arranged based on the determined positions; The method for determining the positions comprises: Obtaining the focal length and magnification of each image acquisition device; For the first image acquisition device, the closest physical position distance between the lens of the first image acquisition device and the surface of the pipe is calculated based on the focal length and magnification, and the position of the first image acquisition device is determined based on the closest physical position distance; For the second image acquisition device, the sum of the physical position distance between the lens of the second image acquisition device and the mirror and the closest physical position distance between the mirror and the surface of the pipe is determined based on the position of the mirror and the focal length and magnification of the second image acquisition device, so as to determine the position of the second image acquisition device; For the third image acquisition device and the fourth image acquisition device, the closest ray distance between the lens of each device and the surface of the pipe is calculated based on the focal length and magnification of each device, and the closest physical position distance between the lens of each device and the surface of the pipe is calculated based on the closest ray distance, the included angle with the normal line of the window glass and the refractive index of the window glass, so as to determine the positions of the third image acquisition device and the fourth image acquisition device.

6. The pipe surface frost analysis test system of claim 5, wherein, The method for determining the positions of the first image acquisition device, the second image acquisition device, the third image acquisition device and the fourth image acquisition device comprises: wherein, represents a focal length of the first image acquisition device, represents a magnification of the first image acquisition device, represents a nearest physical distance of a lens of the first image acquisition device from the surface of the pipe. The sum of the physical distance between the lens of the second image acquisition device and the mirror and the nearest physical distance between the mirror and the pipe surface is determined based on the position of the mirror and the focal length and magnification of the second image acquisition device, and comprises: wherein, denotes the focal length of the second image acquisition device, denotes the magnification of the second image acquisition device, denotes the sum of the physical distance between the lens of the second image acquisition device and the mirror and the closest physical distance between the mirror and the pipe surface, denotes the physical distance between the lens of the second image acquisition device and the mirror, denotes the closest physical distance between the mirror and the pipe surface; The nearest optical distance between the lens and the pipe surface is calculated based on the focal length and magnification of each of the third and fourth image acquisition devices, and the nearest physical distance between the lens and the pipe surface is calculated based on the nearest optical distance, the angle with the windshield normal, and the refractive index of the windshield, and comprises: wherein and respectively denote the focal length and the magnification of the third image acquisition device, and respectively denote the focal length and the magnification of the fourth image acquisition device, and respectively denote the angle between the visual direction of the third image acquisition device and the fourth image acquisition device and the normal of the windshield glass, h denotes the thickness of the windshield glass, denotes the refractive index of the windshield glass, and respectively denote and the angle of refraction in the windshield glass, and respectively denote the closest optical distance of the lens of the third image acquisition device and the fourth image acquisition device to the surface of the pipe, and respectively denote the closest physical distance of the lens of the third image acquisition device and the fourth image acquisition device to the surface of the pipe.

7. A wind tunnel-based method of analyzing pipe surface frosting, characterized by, The method is implemented based on the pipe surface frosting analysis test system according to any one of claims 1 to 6, and comprises: A first field of view rectangle is obtained in real time based on the first and second image acquisition devices, and the outer surface of the pipe is inscribed in the first field of view rectangle; A second field of view rectangle is obtained in real time based on the third and fourth image acquisition devices, and the outer surface of the pipe is inscribed in the second field of view rectangle; An octagon with each side tangent to the outer surface of the pipe is obtained based on the first and second field of view rectangles, and the length of each side of the octagon is calculated; The cross-sectional area and volume of the pipe are calculated based on the length of each side of the octagon.

8. The method of claim 7, wherein the pipe surface is a pipe surface of a pipe used for transporting a fluid. The wet air inflow direction is parallel to the windshield side of the test section of the wind tunnel, and the visual direction of the first and second image acquisition devices is perpendicular to the windshield of the test section of the wind tunnel; The visual direction of the third and fourth image acquisition devices is inclined to the windshield of the test section of the wind tunnel; The length of each side of the octagon is calculated, and comprises: in, and These represent the angles between the visual direction of the third and fourth image acquisition devices and the normal to the viewing window glass, respectively. and These represent the side lengths corresponding to the fields of view of the first image acquisition device and the second image acquisition device within the first field of view rectangle, respectively. and These represent the side lengths corresponding to the fields of view of the third and fourth image acquisition devices within the second field of view rectangle, respectively. This represents the side length corresponding to the field of view of the first image acquisition device in the octagon. In the octagon The length of the opposite side, This represents the side length corresponding to the field of view of the second image acquisition device in the octagon. In the octagon The length of the opposite side, This represents the side length corresponding to the field of view of the third image acquisition device in the octagon. In the octagon The length of the opposite side, This represents the side length corresponding to the field of view of the fourth image acquisition device in the octagon. In the octagon The length of the opposite side.

9. The method of claim 8, wherein the pipe surface frost analysis test is conducted at a temperature of about 0°C to about 10°C. The cross-sectional area and volume of the pipe are calculated based on the length of each side of the octagon, and comprises: wherein denotes the cross-sectional area of the pipe, , , and are intermediate quantities, denotes the volume of the pipe, denotes the length of the pipe.

10. The method of claim 8, wherein the pipe surface is a pipe surface of a pipe used for transporting a fluid. Further comprising: The increment of any one or several of a plurality of parameters within a preset time length is calculated, the plurality of parameters comprising the length of any one or several sides of the octagon, the cross-sectional area of the pipe, and the volume of the pipe.

Images