Film platinum resistor dynamic total temperature probe for measuring transonic flow field

Abstract

The invention belongs to the technical field of dynamic temperature testing, and particularly relates to a film platinum resistor dynamic total temperature probe for measuring a transonic flow field, which comprises a probe head, a probe support rod, a film platinum resistor, a lead hole and a circular pipeline. The probe head is of a wedge-top double-arc prism structure, a thin film platinum resistor temperature sensor is installed at the wedge position, and a thin film platinum resistor wire is led out through a lead hole and a circular pipeline to be connected with external collecting equipment. During measurement, the windward side of the probe head comprises a wedge-top inclined face, a left side face and a right side face, and the leeward side is a cylindrical face. The calibration and measurement data processing method provided by the invention greatly improves the measurement frequency response and the measurement precision of the probe, is suitable for measuring the transient temperature field of the inlet, outlet and interstage transonic flow fields of the turbomachinery, can quickly capture the transient temperature change information of the turbomachinery under different working conditions, and improves the measurement accuracy of the turbomachinery. And an efficient and accurate means for measuring transonic unsteady flow field parameters is provided for turbine experiments.

Description

Technical Field

[0001] The present invention belongs to the technical field of dynamic temperature testing, and relates to a dynamic temperature measuring device for a transonic unsteady flow field, and specifically to a thin-film platinum resistance dynamic total temperature probe for measuring a transonic flow field, which is suitable for testing transonic three-dimensional dynamic flow fields at an inlet, outlet and between stages of an impeller machinery. Background Art

[0002] Temperature is an important thermodynamic parameter in the working process of the impeller. At present, how to quickly and accurately measure the transient temperature field in the field of impeller testing has become an important scientific problem that needs to be solved urgently. When the impeller is running at high speed, the internal core flow field is often in a transonic flow state. In the transonic flow field, the shock wave will cause the pressure and temperature of the flow field to change sharply. Due to the complex flow phenomena such as the mutual interference between the rotor and the stator and the mixing of the vortex system, the transonic flow at the inlet, outlet and interstage of the impeller machinery presents three-dimensionality, non-uniformity, asymmetry and strong non-steadiness, making the test of its internal flow field very difficult, especially the measurement of the temperature of the high-frequency pulsating flow field, which has always been the key and difficulty that needs to be broken through. At present, there are mature test methods for the pressure change of the transonic flow field. Therefore, in order to strengthen the understanding of the transonic flow field of the impeller machinery and master the temperature information of the three-dimensional dynamic flow field of the inlet, outlet and interstage of the impeller machinery, it is necessary to develop a measurement method for the dynamic temperature of the transonic flow field.

[0003] At present, small inertia thermocouples and air-breathing hot wires are often used as test methods for the dynamic temperature of the flow field. However, the existing small inertia thermocouple dynamic temperature sensors have low frequency response. Even if the thin-wire thermocouple temperature sensor with the highest frequency response is used, it still cannot meet the requirements for measuring the three-dimensional dynamic flow field of the inlet, outlet and interstage transonic flow field of the impeller machinery. In addition, small inertia thermocouples are easily affected by environmental factors and will have problems such as material aging and thermoelectric effect drift after long-term use. The air-breathing hot wire temperature probe has an extremely fast thermal response time and can quickly capture transient changes in flow field pressure and temperature. However, the air-breathing hot wire temperature probe is usually made of very thin metal wire, with high thermal manufacturing and maintenance costs, and is prone to breakage and damage, which increases the test cost and unreliability.

[0004] Therefore, in order to quickly and accurately obtain the three-dimensional dynamic flow field temperature information at the inlet, outlet and interstage of the impeller machinery, it is urgently necessary to develop a dynamic total temperature probe that is fast, resistant to airflow erosion, has good durability, has little interference with the flow field, and can measure the three-dimensional transient temperature field at the inlet, outlet and interstage of the impeller machinery. In this way, the dynamic temperature of the unsteady flow field can be accurately measured, which will provide reliable measurement means and technical support for strengthening the understanding of the transonic flow field at the inlet, outlet and interstage of the impeller machinery and the high-performance design of the impeller machinery. Summary of the invention

[0005] The present invention belongs to the technical field of dynamic temperature testing, and specifically relates to a thin-film platinum resistor dynamic total temperature probe for measuring a transonic flow field, comprising a probe head, a probe support rod, a thin-film platinum resistor, a lead hole, and a circular pipe. The probe head is a wedge-top double-arc prism structure, a thin-film platinum resistor temperature sensor is installed at the wedge, and the thin-film platinum resistor wire is led out through the lead hole and the circular pipe to be connected to an external collection device. During measurement, the windward surface of the probe head includes a wedge-top inclined surface, a left side surface, and a right side surface, and the leeward surface is a cylindrical surface.

[0006] In the calibration wind tunnel, a thin-film platinum resistor dynamic total temperature probe for measuring transonic flow fields is calibrated over a wide range. The calibration speed range is 0.8 Mach to 2 Mach, the deflection angle range is -60° to 60°, and the pitch angle range is -30° to 30°. During the wind tunnel test calibration, two thin-film platinum resistors are used to measure the temperature simultaneously. The two thin-film thermal resistors are provided with different constant currents by a signal generator. The two resistors have different initial temperatures, but have the same convective heat transfer surface heat transfer coefficient h. The heat flux ratio of the two thin-film platinum resistors under different working conditions can be obtained. The heat flux ratio is defined as B and satisfies the following equation:

[0007] q1=h(T t -T w1 )

[0008] q2=h(T t -T w2 )

[0009]

[0010] Where, q1, q2——heat flux density of thin film thermal resistor, unit W / m 2 ; Tw1, Tw2——temperature measured by thin film thermal resistor, unit K; Tt——total temperature of the calibration wind tunnel inflow, unit K. The ratio B of heat flux density under different calibration conditions can be obtained by the above calibration method;

[0011] During the test measurement, when the incoming flow condition is known, the corresponding heat flux ratio B can be found from the calibration data. The total temperature T of the measured airflow can be calculated from the measured Tw1 and Tw2 data by the following formula: g :

[0012]

[0013] The present invention provides a thin-film platinum resistance dynamic total temperature probe for measuring transonic flow field, and the technical problems to be solved are: first, solving the problem that the existing dynamic temperature probe is limited by the low frequency response of traditional dynamic temperature sensors. Second, solving the durability problem of the existing dynamic temperature probe.

[0014] The technical solution of the present invention is:

[0015] 1. A thin film platinum resistor dynamic total temperature probe for measuring transonic flow field, comprising a probe head (1), a probe support rod (2), an upper thin film platinum resistor (3), a lower thin film platinum resistor (4), a lead hole (5), and a circular pipe (6), characterized in that: the probe head (1) is a wedge-top double arc prism structure, an upper thin film platinum resistor (3) and a lower thin film platinum resistor (4) are installed at the wedge, and the wires of the upper thin film platinum resistor (3) and the lower thin film platinum resistor (4) are led out through the lead hole (5) and the circular pipe (6) and connected to an external data collection device.

[0016] 2. The windward surface of the probe head (1) includes a wedge top inclined surface, symmetrical left and right surfaces, and the leeward surface is a rear cylindrical surface; the angle between the left and right surfaces of the probe head (1) is 26° to 78°.

[0017] 3. The angle between the front edge line of the left side and the right side of the probe head (1) and the inclined surface of the wedge top is 32° to 56°. The probe head is made of insulating material to reduce heat transfer error during measurement and improve the probe frequency response and measurement accuracy.

[0018] 4. The upper thin-film platinum resistor (3) and the lower thin-film platinum resistor (4) are miniature four-wire thin-film platinum resistors, which are installed at the tip of the probe head (1). The length of the thin-film platinum resistor is 0.5 mm to 3 mm, the width is 0.1 mm to 1.5 mm, and the thickness is 0.01 mm to 0.2 mm. The four-wire measurement can effectively eliminate the influence of the lead resistance on the measurement result, improve the measurement accuracy, and ensure the stability and accuracy of the data.

[0019] 5. The distance between the upper thin-film platinum resistor (3) and the lower thin-film platinum resistor (4) is x, and the value range of x is 0.2 mm ≤ x ≤ 1 mm;

[0020] 6. A lead hole (5) is provided at the junction of the left side and the right side of the probe head (1). The lead hole (5) is connected to the circular pipe (6). The diameter of the lead hole is b, and the value range of b is 0.2 mm ≤ b ≤ 1 mm.

[0021] 7. The distance between the center of the thin film platinum resistor (3) installed on the probe head (1) and the lowest point of the wedge top slope is 1 mm to 3 mm.

[0022] 8. The probe support rod (2) is a columnar structure, which can be a cylinder or a triangular prism, and has a circular channel (6) inside. The diameter of the circular channel (6) is a, and the value range of a is 1 mm ≤ a ≤ 8 mm.

[0023] 9. The wires of the upper thin-film platinum resistor (3) and the lower thin-film platinum resistor (4) pass through the lead hole (5) and the circular pipe (6) and are led out from the tail of the probe.

[0024] The present invention provides a thin-film platinum resistance dynamic total temperature probe for measuring transonic flow field, which has the following beneficial effects:

[0025] Beneficial effect 1: The present invention can effectively improve the measurement accuracy after being calibrated in a standard wind tunnel. Through a precise calibration process, the response of the thin film platinum resistor at different temperature points is ensured to be accurate and reliable, and during measurement, only the incoming flow parameters need to be obtained without understanding the physical properties of the measured medium.

[0026] Beneficial effect two: The present invention is based on the design of a double thin film platinum resistor. The two thin film platinum resistors compensate each other during temperature measurement. The temperature analysis transfer function coefficient is obtained through calibration experiments, and the temperature measurement transfer function of the double thin film platinum resistor dynamic total temperature probe is constructed. The total airflow temperature of the measured flow field is reconstructed, which can greatly improve the frequency response of the dynamic total temperature probe.

[0027] Beneficial effect three: The probe head structure of the present invention is simple and compact, and the wedge-top double-arc prism structure is suitable for transonic flow fields, which helps to reduce the flow separation and reattachment phenomena generated during the flow field measurement process, and ensures the smoothness and continuity of the flow. The wedge-top double-arc prism structure can form stable shock waves and diffusion waves in the transonic flow field, making the measurement of flow field characteristics more accurate and predictable. The wedge-top design helps to reduce the interference of shock waves, thereby obtaining more accurate flow field temperature information. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic structural diagram of a thin-film platinum resistance dynamic total temperature probe for measuring transonic flow field in an embodiment of the present invention.

[0029] Figure 2 yes Figure 1 Top view of the .

[0030] Figure 3 yes Figure 1 A-axis sectional view and partial enlarged view.

[0031] Figure 4 yes Figure 1 B-direction cross-sectional view.

[0032] Figure 5 yes Figure 1 Side view of.

[0033] Among them: 1-probe head, 2-probe support rod, 3-upper thin film thermal resistor, 4-lower thin film thermal resistor, 5-lead hole, 6-circular pipe. DETAILED DESCRIPTION

[0034] The present invention is described in detail below in conjunction with the accompanying drawings and specific implementation examples 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 definite definition of the protection scope of the present invention.

[0035] like Figures 1 to 5 The present invention shows a thin film platinum resistor dynamic total temperature probe for measuring transonic flow field, which is composed of a probe head (1), a probe support rod (2), an upper thin film platinum resistor (3), a lower thin film platinum resistor (4), a lead hole (5), and a circular pipe (6). The probe head (1) is a wedge-top double arc prism structure, an upper thin film platinum resistor (3) and a lower thin film platinum resistor (4) are installed at the wedge, and the wires of the upper thin film platinum resistor (3) and the lower thin film platinum resistor (4) are led out through the lead hole (5) and the circular pipe (6) to be connected to an external data collection device.

[0036] The windward surface of the probe head (1) comprises a wedge top inclined surface, symmetrical left and right surfaces, and the leeward surface is a rear cylindrical surface; the angle between the left and right surfaces of the probe head (1) is 45 degrees.

[0037] The front edge line at the junction of the left side and the right side of the probe head (1) has an angle of 30° with the top slope of the wedge. The probe head is made of heat-insulating material to reduce heat transfer errors during measurement and improve the probe frequency response and measurement accuracy.

[0038] The upper thin-film platinum resistor (3) and the lower thin-film platinum resistor (4) are miniature four-wire thin-film platinum resistors installed at the tip of the probe head (1). The thin-film platinum resistor has a length of 3 mm, a width of 1 mm, and a thickness of 0.05 mm. The four-wire measurement can effectively eliminate the influence of the lead resistance on the measurement result, improve the measurement accuracy, and ensure the stability and accuracy of the data.

[0039] The distance between the upper thin film platinum resistor (3) and the lower thin film platinum resistor (4) is x, and the value range of x is 0.5 mm;

[0040] A lead-in hole (5) is provided at the junction of the left side and the right side of the probe head (1), the lead-in hole (5) is communicated with the circular pipe (6), the diameter of the lead-in hole is b, and the value of b is 0.2 mm.

[0041] The distance between the center of the thin film platinum resistor (3) installed on the probe head (1) and the lowest point of the wedge top slope is 3 mm.

[0042] The probe support rod (2) is a columnar structure with a diameter of 10 mm. A circular channel (6) is opened inside the probe support rod. The diameter of the circular channel (6) is a, and the value of a is 8 mm.

[0043] The upper thin-film platinum resistor (3) and the lower thin-film platinum resistor (4) use micro four-wire thin-film platinum resistor wires to pass through the lead hole (5) and the circular pipe (6) and are led out from the tail of the probe.

[0044] The present invention proposes a data processing method based on a thin film platinum resistor dynamic total temperature probe for measuring a transonic flow field. A wide range calibration is performed on the thin film platinum resistor dynamic total temperature probe for measuring a transonic flow field in a calibration wind tunnel. The calibration speed range is 0.8 Mach to 2 Mach, with an interval of 0.1 Mach, the deflection angle range is -60° to 60°, with an interval of 5°, and the pitch angle range is -30° to 30°, with an interval of 5°. During the wind tunnel test calibration, two thin film platinum resistors are used to perform temperature measurement simultaneously. The two thin film thermal resistors are provided with different constant currents by a signal generator. The two resistors have different initial temperatures but have the same convective heat transfer surface heat transfer coefficient h. The heat flux density ratio of the two thin film platinum resistors under different working conditions can be obtained. The heat flux density ratio is defined as B and satisfies the following equation:

[0045] q1=h(T t -T w1 )

[0046] q2=h(T t -T w2 )

[0047]

[0048] Where, q1, q2——heat flux density of thin film thermal resistor, unit W / m 2 ; Tw1, Tw2——temperature measured by thin film thermal resistor, unit K; Tt——total temperature of the calibration wind tunnel inflow, unit K. The ratio B of heat flux density under different calibration conditions can be obtained by the above calibration method;

[0049] During the test measurement, when the incoming flow condition is known, the corresponding heat flux ratio B can be found from the calibration data. The total temperature T of the measured airflow can be calculated from the measured Tw1 and Tw2 data by the following formula: g :

[0050]

[0051] The present invention is based on a dynamic total temperature probe of a thin film platinum resistor. Through calibration experiments, the temperature analysis transfer function coefficient is obtained, the temperature measurement transfer function of the dynamic total temperature probe of the thin film platinum resistor is constructed, and the total temperature of the airflow in the measured flow field is reconstructed, which can greatly improve the frequency response and measurement accuracy of the dynamic total temperature probe.

Claims

1. A thin film platinum resistor dynamic total temperature probe for measuring transonic flow field, comprising a probe head (1), a probe support rod (2), an upper thin film platinum resistor (3), a lower thin film platinum resistor (4), a lead hole (5), and a circular pipe (6), characterized in that: The probe head (1) is a wedge-top double arc prism structure, and an upper thin-film platinum resistor (3) and a lower thin-film platinum resistor (4) are installed at the wedge. The wires of the upper thin-film platinum resistor (3) and the lower thin-film platinum resistor (4) are led out through a lead hole (5) and a circular pipe (6) to be connected to an external collection device. The windward surface of the probe head (1) includes a wedge top inclined surface, symmetrical left and right surfaces, and the leeward surface is a rear cylindrical surface; The included angle between the left side and the right side of the probe head (1) is 26° to 78°; The front edge line at the junction of the left side and the right side of the probe head (1) has an angle of 32° to 56° with the inclined surface of the wedge top. The probe head is made of heat-insulating material to reduce heat transfer errors during measurement and improve the probe frequency response and measurement accuracy. The upper thin-film platinum resistor (3) and the lower thin-film platinum resistor (4) are miniature four-wire thin-film platinum resistors, which are installed at the tip of the probe head (1). The length of the thin-film platinum resistor is 0.5 mm to 3 mm, the width is 0.1 mm to 1.5 mm, and the thickness is 0.01 mm to 0.2 mm. The four-wire measurement can effectively eliminate the influence of the lead resistance on the measurement result, improve the measurement accuracy, and ensure the stability and accuracy of the data. The distance between the upper thin-film platinum resistor (3) and the lower thin-film platinum resistor (4) is x, and the value range of x is 0.2 mm ≤ x ≤ 1 mm; A lead hole (5) is formed at the junction of the left side and the right side of the probe head (1), the lead hole (5) is connected to the circular pipe (6), the diameter of the lead hole is b, and the value range of b is 0.2 mm ≤ b ≤ 1 mm; The distance between the center of the thin film platinum resistor (3) installed on the probe head (1) and the lowest point of the wedge top slope is 1 mm to 3 mm; The probe support rod (2) is a columnar structure, which can be a cylinder or a triangular prism, and a circular channel (6) is opened inside the probe support rod. The diameter of the circular channel (6) is a, and the value range of a is 1 mm ≤ a ≤ 8 mm. The wires of the upper thin-film platinum resistor (3) and the lower thin-film platinum resistor (4) pass through the lead hole (5) and the circular pipe (6) and are led out from the tail of the probe; The present invention proposes a data processing method based on a thin film platinum resistor dynamic total temperature probe for measuring a transonic flow field. A thin film platinum resistor dynamic total temperature probe for measuring a transonic flow field is calibrated over a wide range in a calibration wind tunnel. The calibration speed range is 0.8 Mach to 2 Mach, the deflection angle range is -60° to 60°, and the pitch angle range is -30° to 30°. During the wind tunnel test calibration, two thin film platinum resistors are used to simultaneously measure the temperature. The two thin film thermal resistors are provided with different constant currents by a signal generator. The two resistors have different initial temperatures but have the same convective heat transfer surface heat transfer coefficient h. The heat flux density ratio of the two thin film platinum resistors under different working conditions can be obtained. The heat flux density ratio is defined as B and satisfies the following equation: q1=h(T t -T w1 ) q2=h(T t -T w2 ) Where, q1, q2——heat flux density of thin film thermal resistor, unit W / m 2 ; Tw1, Tw2——temperature measured by thin film thermal resistor, unit K; Tt——total temperature of the calibration wind tunnel inflow, unit K. The ratio B of heat flux density under different calibration conditions can be obtained by the above calibration method; During the test measurement, when the incoming flow condition is known, the corresponding heat flux ratio B can be found from the calibration data. The total temperature T of the measured airflow can be calculated from the measured Tw1 and Tw2 data by the following formula: g : The present invention is based on a dynamic total temperature probe of a thin film platinum resistor. The temperature analysis transfer function coefficient is obtained through calibration experiments, the temperature measurement transfer function of the dynamic total temperature probe of the thin film platinum resistor is constructed, and the total airflow temperature of the measured flow field is reconstructed. The frequency response and measurement accuracy of the dynamic total temperature probe can be greatly improved. During measurement, only the incoming flow parameters need to be obtained, and there is no need to understand the physical properties of the measured medium.

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