A helical water-cooled wall static pressure probe for measuring high temperature flow field in a combustion chamber

Abstract

This invention belongs to the field of high-temperature flow field pressure testing technology, and discloses a spiral water-cooled wall static pressure probe for measuring the high-temperature flow field of a combustion chamber. Its features include a pressure sensor mounting cavity, a fixed internal thread, a water inlet channel, a water outlet channel, a converging annular cavity, and a fixed external thread. Unlike conventional water-cooled pressure probes, the pressure sensor inside this water-cooled wall static pressure probe is not directly impacted by the high-temperature flow field airflow. However, the heat conduction from the surrounding solid wall surface is greater than that of conventional water-cooled pressure probes, leading to a different cooling structure. In actual measurement of the wall static pressure of the high-temperature flow field inside an aero-engine combustion chamber, the probe is mounted flush with the solid wall surface. After cooling water is introduced, the wall static pressure of the aero-engine combustion chamber can be measured at a high temperature of 2500K, and the probe's frequency response exceeds 80kHz.

Description

Technical Field

[0001] This invention belongs to the field of high temperature pressure testing technology and relates to a dynamic static pressure measurement device for flow fields. Specifically, it relates to a water-cooled wall static pressure probe for measuring the high temperature flow field in a combustion chamber, which is suitable for measuring the dynamic wall static pressure of the high temperature and high pressure flow field in the combustion chamber of an aero-engine. Background Technology

[0002] The combustion chamber of an aero-engine is one of its core components, and its high-temperature, high-pressure environment plays a decisive role in the engine's performance, efficiency, and safety. The pressure distribution and dynamic changes within the combustion chamber directly affect fuel combustion efficiency, thrust output, thermal efficiency, and stable engine operation. Accurate measurement of the high-temperature pressure within the combustion chamber is crucial for optimizing the combustion process, improving engine performance, reducing fuel consumption, minimizing pollutant emissions, and ensuring engine reliability and lifespan. The wall static pressure measurement technology under high-temperature conditions in the combustion chamber is an important branch of aero-engine testing, aiming to accurately measure the static pressure distribution of gases within the combustion chamber, providing critical data support for engine design optimization, performance evaluation, and fault diagnosis.

[0003] However, the extremely high temperatures within the combustion chamber, typically reaching 1500℃-2000℃, make it difficult for traditional pressure sensors to withstand, easily leading to degradation of sensor material performance, signal transmission obstruction, or even damage. The pressure within the combustion chamber is usually between several megapascals and tens of megapascals, requiring the measuring equipment to possess extremely high strength and accuracy, while ensuring stability and reliability under high-pressure conditions. Simultaneously, the complex turbulence and swirling flow within the combustion chamber necessitate accurate capture of pressure distribution in a dynamic flow field for static pressure measurement, posing challenges to the response speed and spatial resolution of the measuring probe. Furthermore, the complex chemical reactions and combustion products within the combustion chamber can interfere with pressure measurements, increasing the difficulty and error. In addition, the high-temperature environment within the combustion chamber can lead to the generation of corrosive gases such as sulfur dioxide and sulfur trioxide, which can corrode the surface and internal structure of the measuring equipment, affecting measurement accuracy and equipment lifespan.

[0004] Commonly used pressure measurement methods, such as PSP pressure-sensitive coating testing technology, have high requirements for optical path arrangement, and the test object is often the pressure on the surface of the test object, making it difficult to meet the requirements for flow field testing in the combustion chamber. Fiber optic pressure sensors, based on fiber optic sensing technology, have advantages such as high temperature resistance, electromagnetic interference resistance, and small size, but currently still face problems such as high cost and limited measurement range. Conventional pressure probe materials cannot withstand temperatures exceeding 1300K, and dynamic pressure sensor heads cannot withstand temperatures exceeding 500K, which can damage the probe during measurement and prevent the measurement from being performed. Water-cooled pressure probes utilize the cooling properties of water to transform the pressure measurement problem in a high-temperature environment into a measurement problem at a relatively low temperature, thus effectively solving the destructive effects of high temperatures on measurement equipment. After decades of development, water-cooled pressure probe technology has been continuously improved, with significant progress in its structural design, cooling efficiency, measurement accuracy, and reliability, becoming one of the important tools for high-temperature pressure measurement in aero-engine combustion chambers.

[0005] The basic structure of a water-cooled wall static pressure probe consists of three parts: a probe housing, a cooling channel, and a pressure sensor. The probe head is directly exposed to the high-temperature environment of the combustion chamber to collect pressure signals. The cooling system uses circulating water to remove heat from the probe head, lowering the internal temperature of the probe to the range where the pressure sensor can operate normally. The pressure sensor is installed inside the probe and measures the cooled pressure signal to reflect the actual pressure inside the combustion chamber. The working principle of the water-cooled pressure probe can be summarized as follows: utilizing the high specific heat capacity and good thermal conductivity of water, heat from the high-temperature environment is quickly transferred to the outside, thereby protecting the internal pressure sensor from high-temperature damage and ensuring the accuracy and stability of the measurement signal.

[0006] Dynamic pressure probes are difficult to miniaturize, as large sizes can severely interfere with the measured flow field. Furthermore, dynamic pressure probes are prohibitively expensive. Existing probes with water-cooling structures (invention patent: A water-cooled probe, 2017207630951) introduce cooling water through a single inlet, which may lead to uneven water intake and potentially cause localized probe erosion, making it impossible to measure static pressure within the combustion chamber. Existing water-cooled pressure probes for measuring the internal flow field of the combustion chamber (invention patent: An omnidirectional four-hole water-cooled dynamic pressure probe for measuring the combustion chamber recirculation flow field, 2024109925656) measure two-dimensional flow parameters of the combustion chamber recirculation flow field. However, their manufacturing process is complex and their spatial resolution is low, making it impossible to measure the wall static pressure at multiple points within the combustion chamber.

[0007] Existing water-cooled pressure probes are insufficient to meet the testing requirements for measuring the static pressure of the combustion chamber walls under high-temperature conditions, especially at extreme temperatures of 2500K. Existing probes either fail to meet the testing needs in high-temperature environments or have complex manufacturing processes that result in excessively high costs and are inconvenient to produce. Therefore, there is an urgent need for a water-cooled wall static pressure probe that is suitable for high temperatures, can prevent localized ablation, and has a relatively low manufacturing cost, capable of achieving static pressure measurement of the combustion chamber walls in aero-engines. Summary of the Invention

[0008] The technical problem to be solved by this invention is: since existing pressure probes cannot meet the requirements for measuring the static pressure of the wall in the high-temperature environment of the combustion chamber, especially the requirements for the static pressure of the wall at the extreme high temperature of 2500K, a water-cooled dynamic static pressure probe that is resistant to high temperature, fast response and can be used to measure the static pressure of the wall in the high-temperature and high-pressure environment of the combustion chamber of an aero-engine is invented.

[0009] The temperature inside the combustion chamber is extremely high, typically exceeding 1500℃. The probe needs to be made of a material capable of maintaining structural stability and avoiding material property degradation (such as strength reduction, deformation, or melting) at such high temperatures. For example, while commonly used high-temperature alloys offer some degree of high-temperature resistance, they may still experience creep and other problems under prolonged exposure to high temperatures. When measuring the harsh high temperatures inside the combustion chamber, the ambient temperature is also very high, and excessively high temperatures can damage the probe. Therefore, an efficient and reliable cooling measure is needed to reduce the temperature around the probe support. Furthermore, the flow field inside the combustion chamber is complex and highly unsteady. Measuring the static pressure on the combustion chamber wall with minimal flow field interference is a major challenge. One approach is to create multiple static pressure holes in the solid wall surface in contact with the flow field to be measured and install pressure sensors within these holes. However, the temperatures of the flow field and the solid wall surface inside the combustion chamber are very high, and the pressure sensors located within the static pressure holes cannot withstand such high temperatures. Therefore, there is an urgent need to invent a fast-response static pressure probe with a special cooling structure, minimal flow field interference, and the ability to measure the static pressure on the walls of aero-engine combustion chambers.

[0010] Besides the inherent temperature resistance of the materials, an effective thermal protection structure is also required. Water cooling is one of the key methods, but ensuring that the cooling water can continuously and uniformly cool the probe in high-temperature environments, while preventing cooling water leakage or vaporization that could lead to cooling failure, is a significant challenge. For example, the design of the cooling water channels needs to consider the uniform distribution of water flow, reasonable control of flow velocity, and sealing performance to prevent high-temperature gases from entering the cooling water channels and affecting the cooling effect. Furthermore, conventional water-cooled pressure probes have insufficient spatial resolution, and the method of measuring the static pressure in different areas of the combustion chamber by inserting the probe into the flow field can interfere with the flow field. Since the flow field inside an aero-engine combustion chamber contains complex turbulence and swirl, the measurement results are easily affected by interference and become inaccurate. Therefore, it is considered to open multiple static pressure holes at the solid wall surface in contact with the flow field in the combustion chamber, and then install water-cooled wall static pressure probes with special cooling structures in the static pressure holes.

[0011] Unlike conventional water-cooled pressure probe testing environments, the pressure sensor inside this water-cooled wall static pressure probe is not directly impacted by the high-temperature flow field. Conversely, the heat conduction from the surrounding solid walls is greater than that of conventional water-cooled pressure probes, leading to a difference in cooling structure between the two. Therefore, this invention provides a water-cooled wall static pressure probe with a spiral structure for measuring the high-temperature flow field inside an aero-engine combustion chamber. During measurement, cooling water is introduced into the probe's inlet, flows through the probe's interior, and is discharged through the outlet. Since the heat flux exerted on the probe's sidewalls by the surrounding solid walls is essentially uniform, the probe's cooling structure needs to be rationally designed to ensure consistent circumferential cooling. Here, a spiral structure is considered for cooling the water-cooled wall static pressure probe. Six spiral water-cooling channels are formed inside the probe: three are inlet channels, and three are outlet channels. The six cooling channels converge around the pressure sensing orifice and circulate with each other under the influence of pressure difference. A unique spiral cooling structure ensures that the water-cooled wall static pressure probe maintains a similar cooling effect in the circumferential direction along its axis, preventing thermal stress concentration caused by excessive temperature differences in the probe housing and improving its testing capabilities in high-temperature environments. In actual measurements of the wall static pressure of an aero-engine combustor, the water-cooled wall static pressure probe is fixed to the solid wall region of the combustor and installed flush to enhance its fast response. After testing and data processing, the wall static pressure and its pulsation in the aero-engine combustor flow field can be obtained. With the introduction of cooling water, the sensor temperature can be reduced to below 500K, enabling measurements of the wall static pressure in high-temperature flow fields at 2500K, with a probe frequency response exceeding 80kHz.

[0012] The solution of this invention is:

[0013] 1. A spiral water-cooled wall static pressure probe for measuring the high-temperature flow field of a combustion chamber, mainly comprising a pressure sensor mounting cavity (1), a fixed internal thread (2), water inlet channels (3), (5), (7), water outlet channels (4), (6), (8), a confluence ring cavity (9), and a fixed external thread (10), characterized in that: the probe is approximately cylindrical in shape, with a pressure sensing hole on it, the pressure sensing hole being connected to the pressure sensor mounting cavity (1), the probe having a diameter of 5 mm to 20 mm and a length of 10 mm to 100 mm, the inner diameter of the pressure sensing hole being 0.2 mm to 2 mm, the inner diameter of the sensor mounting cavity being 1 mm to 2 mm, the probe housing being made of Inconel alloy high-temperature resistant material, and its surface being coated with a high-temperature resistant heat insulation coating.

[0014] 2. Furthermore, the probe has six cooling water channels extending outward in the circumferential direction at its bottom, three of which are cooling water inlet channels (3), (5), and (7), and three are cooling water outlet channels (4), (6), and (8). Each cooling channel is circular in the cross section perpendicular to the probe axis, with a diameter of 0.5 mm to 3 mm. The inlet and outlet cooling channels are spaced apart from each other, but they do not intersect each other. Their center lines are parallel to each other before entering the confluence annular cavity (9).

[0015] 3. Furthermore, the center lines of the cooling water inlet channels (3), (5), and (7) are all variable pitch spirals before entering the confluence annular cavity (9), so that the cooling water has better flow characteristics in the cooling water inlet channels (3), (5), and (7). The pitch of the center lines of the cooling water inlet channels (3), (5), and (7) before entering the confluence annular cavity (9) is 2 mm to 80 mm.

[0016] 4. Furthermore, the probe is provided with a fixed external thread (10) to fix the water-cooled wall static pressure probe in the static pressure hole opened in the side wall of the combustion chamber flow field. The pressure sensor mounting cavity (1) inside the probe is provided with a fixed internal thread (2) to fix the pressure sensor inside the probe. The pressure sensor is provided with an external thread to achieve mutual cooperation with the fixed internal thread (2) opened in the pressure sensor mounting cavity (1) inside the probe.

[0017] 5. Further, the inner diameter of the confluence annular cavity (9) opened at the top of the probe is 2 mm to 6 mm, the outer diameter is 6 mm to 15 mm, and the height of the annular cavity is 0.5 mm to 3 mm.

[0018] This invention discloses a water-cooled wall static pressure probe for measuring the high-temperature flow field in a combustion chamber. After shock tube calibration, calibration data can be obtained. In actual measurement of the wall static pressure of the high-temperature flow field inside an aero-engine combustion chamber, the probe is mounted flush with the solid wall surface. With the introduction of cooling water, the measurement of the wall static pressure of the aero-engine combustion chamber can be achieved at a high temperature of 2500K, and the probe's frequency response exceeds 80kHz.

[0019] This invention, a spiral water-cooled wall static pressure probe for measuring the high-temperature flow field in a combustion chamber, has the following beneficial effects:

[0020] Benefit 1: This probe enables measurements in high-temperature environments. After shock tube calibration, this invention can be used to measure the static pressure on the combustion chamber walls of aero-engines, providing experimental data for improving the performance of aero-engine combustion chambers. Compared with conventional measurement probes, this probe enables measurements in high-temperature environments. After injecting cooling water, the cooling effect around the sensing part of the probe is improved, causing the temperature around the dynamic pressure sensor head inside the probe to drop below 500K.

[0021] Benefit Two: The probe has a simple manufacturing process and low manufacturing cost. Compared with some new high-temperature pressure measurement technologies (such as fiber optic pressure sensors), the water-cooled pressure probe has a relatively low cost and high technological maturity, offering good cost-effectiveness. This has led to its widespread application in the field of high-temperature pressure measurement in aero-engine combustion chambers, especially in situations where cost control is stringent.

[0022] Benefit 3: Less interference with the flow field. Compared with conventional water-cooled pressure probes that extend into the flow field for measurement, creating static pressure holes in the wall and then installing the water-cooled wall static pressure probe on the wall can reduce the interference to the flow field caused by the probe measurement.

[0023] Benefit 4: Prevents localized probe erosion. The cooling channel employs a variable pitch design, optimizing the flow of cooling water and reducing its flow resistance. This ensures uniform cooling water flow within the channel, preventing localized erosion caused by cavities within the fluid.

[0024] Benefit 5: Avoids thermal stress concentration on the probe. The probe uses spiral cooling, ensuring a relatively uniform cooling effect along the circumferential direction of the probe axis. This prevents thermal stress concentration on the probe housing due to temperature differences, thus increasing the probe's lifespan.

[0025] Benefit Six: The internal cooling structure of this probe enhances the convective heat transfer between the cooling water and the high-temperature probe. The cooling channels are connected to the confluence annular cavity at the probe head. The cooling water pressure is high within the confluence annular cavity, raising the boiling point of the cooling water and enabling it to withstand higher temperatures without phase change. Simultaneously, the water flow from the inlet channel directly impacts the high-temperature probe, forming impact cooling and enhancing the heat transfer between the cooling water and the high-temperature fluid side of the probe shell. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of a spiral water-cooled wall static pressure probe for measuring the high-temperature flow field in a combustion chamber, according to an embodiment of the present invention.

[0027] Figure 2 yes Figure 1 Sectional view of section AA.

[0028] Figure 3 yes Figure 1 BB section sectional view.

[0029] Figure 4 yes Figure 1 The CC section sectional view.

[0030] Figure 5 yes Figure 1 A bottom view.

[0031] Wherein: 1-pressure sensor mounting cavity, 2-fixed internal thread, 3, 5, 7-water inlet channel, 4, 6, 8-water outlet channel, 9-merging ring cavity, 10-fixed external thread. Detailed Implementation

[0032] The present invention will now be described in detail with reference to the accompanying drawings and a specific embodiment, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more explicit definition of the scope of protection of the present invention.

[0033] like Figure 1 As shown, this embodiment introduces a water-cooled wall static pressure probe for measuring the high-temperature flow field of a combustion chamber. This embodiment introduces a spiral water-cooled wall static pressure probe for measuring the high-temperature flow field of a combustion chamber, mainly including a pressure sensor mounting cavity (1), a fixed internal thread (2), water inlet channels (3), (5), (7), water outlet channels (4), (6), (8), a confluence ring cavity (9), and a fixed external thread (10). The probe is approximately cylindrical in shape and has a pressure sensing hole on it. The pressure sensing hole is connected to the pressure sensor mounting cavity (1). The probe has a diameter of 10 mm and a length of 60 mm. The inner diameter of the pressure sensing hole is 0.5 mm, the inner diameter of the sensor mounting cavity is 1 mm, and the probe shell is made of Inconel alloy high-temperature resistant material, and its surface is coated with a high-temperature resistant heat insulation coating.

[0034] Figure 2 for Figure 1 In the AA view, the center lines of the cooling water inlet channels (3), (5), and (7) are all variable pitch spirals before entering the confluence annular cavity (9) to facilitate better flow characteristics of the cooling water in the cooling water inlet channels (3), (5), and (7). The pitch of the center lines of the cooling water inlet channels (3), (5), and (7) before entering the confluence annular cavity (9) is 6 mm, and the pitch of the cooling water inlet channels (3), (5), and (7) on the inlet and outlet sides is 40 mm. The probe has a fixed external thread (10) to fix the water-cooled wall static pressure probe in the static pressure hole opened on the side wall of the combustion chamber flow field. The pressure sensor mounting cavity (1) inside the probe has a fixed internal thread (2) to fix the pressure sensor inside the probe. The pressure sensor has an external thread to cooperate with the fixed internal thread (2) opened in the pressure sensor mounting cavity (1) inside the probe. The confluence ring cavity (9) opened at the top of the probe has an inner diameter of 2 mm to 6 mm, an outer diameter of 6 mm to 15 mm, and a ring cavity height of 0.5 mm to 3 mm.

[0035] Figure 3 and Figure 4 They are respectively Figure 1 BB view and CC view, Figure 5 for Figure 1 The bottom view shows that the probe has six cooling water channels extending outward in the circumferential direction. Among them, three are cooling water inlet channels (3), (5), and (7), and three are cooling water outlet channels (4), (6), and (8). Each cooling channel is circular on the cross section perpendicular to the probe axis with a diameter of 2 mm. The inlet and outlet cooling channels are spaced apart from each other, but they do not intersect each other. The center lines are parallel to each other before entering the confluence ring cavity (9).

[0036] This invention presents a water-cooled wall static pressure probe for measuring the high-temperature flow field in a combustion chamber. After shock tube calibration, calibration data can be obtained. In actual measurement of the wall static pressure of the high-temperature flow field inside an aero-engine combustion chamber, the probe is flush-mounted to the solid wall surface. After cooling water is introduced, the static pressure of the aero-engine combustion chamber wall can be measured at a high temperature of 2500K, and the probe's frequency response exceeds 80kHz.

Claims

1. A helical water-cooled wall surface static pressure probe for measuring a high temperature flow field in a combustion chamber, characterized by: The device includes a pressure sensor mounting cavity (1), a fixed internal thread (2), water inlet channels (3), (5), and (7), water outlet channels (4), (6), and (8), a confluence ring cavity (9), and a fixed external thread (10). Its features include: a probe with an approximately cylindrical shape, a pressure sensing hole connected to the pressure sensor mounting cavity (1), a probe diameter of 5 mm to 20 mm, a length of 10 mm to 100 mm, an inner diameter of 0.2 mm to 2 mm for the pressure sensing hole, an inner diameter of 1 mm to 2 mm for the sensor mounting cavity, and a probe housing made of Inconel alloy high-temperature resistant material, with its surface coated with a high-temperature resistant heat-insulating coating. The probe has six cooling water channels extending outwards circumferentially from its bottom. Three of these are cooling water inlet channels (3), (5), and (7), and the other three are cooling water outlet channels (4), (6), and (8). Each cooling channel is circular in cross-section perpendicular to the probe axis, with a diameter of 0.5 mm to 3 mm. The three cooling water inlet channels (3), (5), and (7) and the three cooling water outlet channels (4), (6), and (8) are spaced apart from each other, but they do not intersect. Their centerlines are parallel to each other before entering the converging annular cavity (9). The centerlines of the cooling water inlet channels (3), (5), and (7) are all variable pitch helical lines before entering the confluence annular cavity (9), so that the cooling water has better flow characteristics in the cooling water inlet channels (3), (5), and (7). The pitch of the centerlines of the cooling water inlet channels (3), (5), and (7) before entering the confluence annular cavity (9) is 2 mm to 80 mm. The probe is provided with a fixed external thread (10) to fix the water-cooled wall static pressure probe in the static pressure hole opened on the side wall of the combustion chamber flow field. The pressure sensor mounting cavity (1) inside the probe is provided with a fixed internal thread (2) to fix the pressure sensor inside the probe. The pressure sensor is provided with an external thread to achieve mutual cooperation with the fixed internal thread (2) opened in the pressure sensor mounting cavity (1) inside the probe. The confluence ring cavity (9) opened at the top of the probe has an inner diameter of 2 mm to 6 mm, an outer diameter of 6 mm to 15 mm, and a ring cavity height of 0.5 mm to 3 mm.

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