CN117030269A - Isentropic efficiency high-precision measuring device for blade machine - Google Patents

Abstract

The invention belongs to the technical field of blade machine testing, and specifically relates to a high-precision measuring device for blade machine isentropic efficiency, which includes: a temperature sensor, a windward side pressure induction pipe, a leeward side pressure induction pipe, a mounting base, an insulating sealant, an air outlet, Circular channel, temperature sensor cable, probe support rod, air inlet, and leeward side mounting hole. It is characterized in that: the probe support rod has a "丨" shaped structure, and there is an air inlet on the windward side of the probe support rod. The pressure pipe on the windward side and the temperature sensor are installed parallel to the air inlet through the mounting base. There are air outlets on the left and right of the air inlet. The air outlet is led from the leeward side of the probe pole. There is a leeward opening on the leeward side of the probe pole. Side mounting hole, the leeward side pressure pipe is fixed in the leeward side mounting hole through insulating sealant. The invention can achieve high-precision measurement of the isentropic efficiency of blade machines such as fans, compressors, and turbines while minimizing interference to the measured flow field.

Description

A high-precision measuring device for blade machine isentropic efficiency

Technical field

The invention belongs to the technical field of blade machine testing, and specifically relates to a high-precision measuring device for blade machine isentropic efficiency, which can realize the isentropic efficiency of blade machines such as fans, compressors, and turbines while minimizing interference to the measured flow field. high-precision measurement.

Background technique

Blade machines are widely used in aviation and other industrial fields as energy conversion machines. Almost all modern aerospace engines use axial flow blade machines: fans, compressors, and turbines. Therefore, the efficiency of the blade machine directly determines the performance of the aeroengine. The efficiency of a blade machine is an indirect measurement, and isentropic efficiency is one of the most common methods used to calculate its efficiency. The calculation formula of the isentropic efficiency of the blade machine is as follows:

Fan\compressor isentropic efficiency:

Turbine isentropic efficiency:

Where: η _c ——fan\compressor isentropic efficiency

T _t1 ——Total compressor inlet temperature, K

T _t2 ——Total compressor outlet temperature, K

π _c ——Total pressure ratio of compressor

k——specific heat ratio

η _Torbo - Turbine isentropic efficiency

T _t3 ——Turbine inlet total temperature, K

T _t4 ——Turbine outlet total temperature, K

P _t3 ——Turbine inlet total pressure, Pa

P _s4 ——Turbine outlet static pressure, Pa

It can be seen from the above formula that in order to measure the isentropic efficiency of the blade machine, it is necessary to measure the total temperature and total pressure at the inlet of the blade machine, and the total temperature, total pressure and static pressure at the outlet. When measuring the inlet and outlet parameters of a blade machine, most existing measuring devices use a separate pressure measuring device and a separate temperature measuring device to measure pressure and temperature respectively. The disadvantages are:

1. Pressure and temperature cannot be measured at the same point at the same time, and the measurement parameters do not come from the same streamline. The flow in the blade machine has strong spatial non-uniformity, which will cause additional errors in the final measurement results.

2. When the probe is extended into the flow field of the blade machine for measurement, it will inevitably interfere with the flow field being measured. However, in the existing technology, a separate pressure measuring device and a separate temperature measuring device are used for measurement. Too many probes will cause greater interference to the measured flow field, ultimately increasing the measurement error and causing blockage of the flow field.

At the same time, the existing temperature and pressure combination probe structures are generally designed to combine a single-hole pressure probe with a temperature measuring point or a multi-hole pressure probe with a temperature measuring point. The disadvantages are: 1. The combination of a multi-hole pressure probe and a temperature measuring point The design requires a relatively large space on the probe surface, making the spatial resolution of the flow field measurement poor, resulting in larger measurement errors; 2. Although the design of the single-hole pressure probe combined with the temperature measuring point improves the flow field measurement Spatial resolution, but in order to ensure the accuracy of pressure measurement, a single pressure measuring point needs to rotate the probe to correct the pressure measurement value, but this cannot ensure that the temperature and pressure measuring points are on the same streamline, resulting in extraneous Error; 3. In order to ensure the measurement accuracy, the temperature measuring points generally adopt the design of stagnation cover or shielding cover, which greatly increases the size of the probe head and makes it impossible to measure the flow field between the two poles of the narrow blade machine.

Therefore, existing measurement devices can no longer meet the demand for high-precision measurement of isentropic efficiency of blade machines, and there is an urgent need for a high-precision measurement device for isentropic efficiency of blade machines to achieve high-precision measurement of isentropic efficiency of blade machines.

Contents of the invention

The present invention is a high-precision measuring device for isentropic efficiency of a blade machine. The entire probe adopts a "丨"-shaped design. Its measuring device is different from the previous separate pressure measuring device and temperature measuring device. The device of the present invention is a combined pressure and temperature measurement device. The device can measure the total temperature, total pressure, static temperature, static pressure, Mach number, speed, density and entropy of the airflow through a single device. The device of the present invention abandons the traditional design idea of a total temperature measuring device. Instead, based on the applicant's years of research, it creatively proposes to combine pressure measuring points and temperature measuring points on the windward side to enhance the convection between the air flow and the temperature sensor. Heat exchange improves the total temperature recovery coefficient and reduces the problem of large temperature measurement radiation errors during high-temperature measurements. There is no need to consider the airflow insensitivity angle of total temperature measurement; at the same time, another pressure sensor is installed on the leeward side. Point-to-point correction of the pressure measurement points on the windward side not only ensures the spatial resolution of total temperature and total pressure measurement, but also effectively reduces the total pressure measurement error.

The invention provides a high-precision measuring device for the isentropic efficiency of a blade machine. The technical problems to be solved are: first, solving the problem that the existing measuring device cannot simultaneously measure the total temperature, total pressure, static temperature and static pressure of the flow field with high precision. , Mach number, speed, density, entropy and other parameters; second, solve the problems of large radiation error, low total temperature recovery coefficient, and small insensitivity angle of existing temperature measurement devices; third, solve the problems of existing temperature measurement devices The problem is that speed error correction cannot be independently performed for different Mach number operating conditions. Fourth, solve the problems of low spatial resolution and low measurement accuracy of existing pressure and temperature combined measurement devices.

The technical solution of the present invention is:

1. A high-precision measuring device for the isentropic efficiency of a blade machine, consisting of a temperature sensor (1), a windward side pressure pipe (2), a leeward side pressure pipe (3), a mounting base (4), and an insulating sealant (5 ), an air outlet (6), a circular channel (7), a temperature sensor cable (8), a probe rod (9), an air inlet (10), and a leeward side mounting hole (11). It is characterized by: : The probe support rod (9) has a "丨"-shaped structure. There is an air inlet (10) on the windward side of the probe support rod (9), and the pressure tube (2) and the temperature sensor (1) on the windward side pass through The mounting base (4) is installed parallel to the air inlet (10). The windward side pressure pipe (2) and the temperature sensor cable (8) lead out the probe support rod (9) through the circular channel (7), and the air inlet There are air outlets (6) on the left and right sides of the mouth (10). The air outlet (6) is led from the leeward side of the probe support rod (9). The leeward side of the probe support rod (9) has a leeward side installation hole (11). The leeward side pressure pipe (3) is fixed in the leeward side installation hole (11) through the insulating sealant (5), and leads out from the circular channel (7) to the tail of the probe rod (9).

2. Further, the probe support rod (9) has a length of 10 to 110 mm and a diameter of 8 to 16 mm. The probe support rod (9) has an air inlet (10) on the windward side, and the air inlet (10) consists of The contraction section is composed of a cylindrical section. The meridian line of the contraction section is a lemniscate or a 30-60° arc line. The diameter of the cylindrical section is 2-6 mm and the length is 4-10 mm. Its center line is 5-5 mm from the top of the probe. 15 mm, and there are air outlets (6) on the left and right sides of the air inlet (10). The air outlets (6) are led from the leeward side of the probe support rod (9), with a diameter of 0.1 to 2 mm.

3. Further, the temperature sensor (1) and the windward side pressure pipe (2) are fixed in the mounting base (4) through the insulating sealant (5). Their center lines are parallel to the direction of the inflow, and the temperature sensor (1) head The distance between the probe pole (9) and the windward side is 2 to 6 mm. The temperature sensor cable (8) is led out of the probe pole (9) through the circular channel (7). The front end of the pressure pipe (2) on the windward side is 2 to 6 mm away. The front end of the air inlet (10) is 1 to 4 mm, and the rear end leads to the tail of the probe rod (9) through the circular channel (7). The front end of the windward side pressure tube (2) is 1 to 4 mm longer than the front end of the temperature sensor (1). 3mm.

4. Further, the leeward side pressure pipe (3) is fixed in the leeward side installation hole (11) through the insulating sealant (5), and its center line is collinear with the windward side pressure pipe (2). (3) The head is 1 to 4 mm away from the leeward side of the probe pole (9), and the tail is led out from the tail of the probe pole (9) through the circular channel (7).

5. Further, the diameter of the circular channel (7) is 2 to 6 mm, its center line is 0.5 to 5 mm away from the center line of the probe support rod (9), its top is flush with the upper end of the air inlet (10), and its lower end runs through Probe support (9).

The invention is a high-precision measuring device for isentropic efficiency of a blade machine, which has the following beneficial effects:

Beneficial effect one: a single device of the present invention can realize the measurement of the total temperature, total pressure, static temperature, static pressure, Mach number, speed, density, and entropy of the blade machine flow field. It has a compact structure and small size, which effectively reduces the need for the measured The interference of the flow field improves the test accuracy.

Beneficial Effect 2: The present invention uses the windward side pressure measuring point to obtain the incoming flow direction, and then rotates the probe rod so that the windward side inlet faces the incoming flow direction. Therefore, the present invention can perform high-temperature measurement for all incoming flow angles. Accurate measurement without the problem of small insensitive angle of traditional temperature probes.

Beneficial effect three: the temperature sensor and the windward side pressure pipe are located in the same air inlet, so that the measured values of the total temperature and total pressure are on the same streamline, and the windward side pressure pipe and the leeward side pressure pipe are located on the same horizontal line. Therefore, the total pressure measured on the windward side and the leeward side is also on the same streamline, and the measurement accuracy is greatly improved.

Beneficial Effect 4: The windward side pressure inducing tube is used to enhance the air flow disturbance in the air inlet, which enhances the heat exchange between the air flow and the temperature sensor, making the total temperature recovery coefficient of the temperature sensor high and stable. At the same time, the front end of the windward side pressure inducing tube is longer than the temperature sensor. The front end reduces the total pressure loss when the airflow reaches the windward side pressure pipe and improves the total pressure measurement accuracy.

Beneficial effect five: In the present invention, the temperature sensor is installed inside the probe, so that when measuring high-temperature air flow, the shielding effect is good and the radiation error caused by thermal radiation is greatly reduced.

Beneficial effect 6: The probe of the present invention has a "丨" shape and is small in size, and is suitable for flow field measurement between two poles of a narrow blade machine.

Description of the drawings

Figure 1 is a schematic structural diagram of a high-precision measuring device for isentropic efficiency of a blade machine in an embodiment of the present invention.

FIG. 2 is a partial enlarged view of FIG. 1 .

Fig. 3 is a view taken along line A-A in Fig. 1 .

Fig. 4 is a view in direction B of Fig. 1 .

Fig. 5 is a view of arrow C in Fig. 1 .

Fig. 6 is a D-direction view of Fig. 5 .

Marks and names of corresponding parts in the drawings: 1-temperature sensor; 2-windward side pressure pipe; 3-leeward side pressure pipe; 4-mounting base; 5-insulation sealant; 6-air outlet; 7-circle shaped channel; 8-temperature sensor cable; 9-probe support; 10-air inlet; 11-leeward side mounting hole.

Detailed ways

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, and the protection scope of the present invention can be more clearly defined.

Embodiment 1: Figures 1 to 5 show a high-precision measurement device for isentropic efficiency of a blade machine, which consists of a temperature sensor (1), a windward side pressure pipe (2), a leeward side pressure pipe (3), and an installation Seat (4), insulating sealant (5), air outlet (6), circular channel (7), temperature sensor cable (8), probe rod (9), air inlet (10), leeward side It consists of a mounting hole (11), and is characterized in that: the probe support rod (9) has a "丨"-shaped structure, an air inlet (10) is opened on the windward side of the probe support rod (9), and a pressure pipe on the windward side (2) is installed parallel to the temperature sensor (1) in the air inlet (10) through the mounting base (4), and the windward side pressure pipe (2) and the temperature sensor cable (8) are led out through the circular channel (7) The probe support rod (9) has air outlets (6) on the left and right sides of the air inlet (10). The air outlet (6) is led from the leeward side of the probe support rod (9). There is a leeward side installation hole (11), the leeward side pressure pipe (3) is fixed in the leeward side installation hole (11) through the insulating sealant (5), and the probe support rod (7) is led out from the circular channel (7) 9)Tail.

The probe support rod (9) has a length of 80 mm and a diameter of 8 to 16 mm. The probe support rod (9) has an air inlet (10) on the windward side. The air inlet (10) is composed of a contraction section and a cylindrical section. , the meridional profile of the contraction section is a 60° arc line, the diameter of the cylindrical section is 4 mm, the length is 6 mm, its center line is 6 mm from the top of the probe, and there are air outlets (6) on the left and right of the air inlet (10). The air outlet (6) is led from the leeward side of the probe support rod (9) and has a diameter of 0.8 mm.

The temperature sensor (1) and the windward pressure pipe (2) are fixed in the mounting base (4) through insulating sealant (5). Their center lines are parallel to the direction of flow. The head of the temperature sensor (1) is far away from the probe. The length of the support rod (9) is 4 mm on the windward side. The temperature sensor cable (8) is led out of the tail of the probe support rod (9) through the circular channel (7). The front end of the pressure pipe (2) on the windward side is away from the air inlet (10). The front end is 2.5 mm, and the rear end leads to the tail of the probe rod (9) through the circular channel (7). The front end of the windward side pressure tube (2) is 1.5 mm longer than the front end of the temperature sensor (1).

The leeward side pressure pipe (3) is fixed in the leeward side installation hole (11) through the insulating sealant (5). Its center line is collinear with the windward side pressure pipe (2). The leeward side pressure pipe (3) head The part is 1 to 4 mm away from the leeward side of the probe pole (9), and the tail is led out from the tail of the probe pole (9) through the circular channel (7).

The circular channel (7) has a diameter of 4 mm, its center line is 3 mm away from the center line of the probe support rod (9), its top is flush with the upper end of the air inlet (10), and its lower end runs through the probe support rod (9).

The usage process of the present invention is:

The invention needs to be calibrated before use. First, calibrate the pressure measuring points on the windward side and leeward side. In a calibrated wind tunnel with known incoming flow Mach number and temperature, make the incoming flow flow through the head of the device and measure the conditions under different working conditions. The pressure on the windward side and the leeward side of the device and the temperature of the temperature sensors are used to determine the calibration curves of the total pressure and total temperature on the windward and leeward sides at different Mach numbers and different deflection angles based on the data obtained from the calibration.

When in use, use the windward side pressure measuring point to determine the direction of airflow. Rotate the device so that the windward side pressure pipe and the temperature sensor are facing the incoming flow. Then collect the windward side, leeward side pressure measurement values and the temperature sensor measurement values, and obtain them through the calibration curve. The total temperature T _s of the incoming flow, the total pressure P _t , and the static pressure P _s .

Then combined with the following relationship:

c ² =γRT _s

P＝ρRT

The Mach number, static temperature, velocity, density and entropy of the flow field can be obtained. Among them, P _T and P _s are the total pressure and static pressure of the flow field, T _T and T _s are the total temperature and static temperature of the flow field, the subscripts 1 and 2 respectively indicate that the parameters come from different times, and s is the Entropy, γ is the adiabatic index of the flow field, Ma is the Mach number of the flow field, v is the velocity of the flow field, ρ is the density, c is the local sound speed of the flow field, and R is the gas constant.

Claims (1)

1. A high-precision measuring device for the isentropic efficiency of a blade machine, consisting of a temperature sensor (1), a windward side pressure pipe (2), a leeward side pressure pipe (3), a mounting base (4), and an insulating sealant (5 ), an air outlet (6), a circular channel (7), a temperature sensor cable (8), a probe rod (9), an air inlet (10), and a leeward side mounting hole (11). It is characterized by: : The probe support rod (9) has a "丨"-shaped structure. There is an air inlet (10) on the windward side of the probe support rod (9), and the pressure tube (2) and the temperature sensor (1) on the windward side pass through The mounting base (4) is installed parallel to the air inlet (10). The windward side pressure pipe (2) and the temperature sensor cable (8) lead out the probe support rod (9) through the circular channel (7), and the air inlet There are air outlets (6) on the left and right sides of the mouth (10). The air outlet (6) is led from the leeward side of the probe support rod (9). The leeward side of the probe support rod (9) has a leeward side installation hole (11). The leeward side pressure pipe (3) is fixed in the leeward side installation hole (11) through the insulating sealant (5), and leads out from the circular channel (7) to the tail of the probe rod (9); The probe support rod (9) has a length of 10 to 110 mm and a diameter of 8 to 16 mm. The probe support rod (9) has an air inlet (10) on the windward side. The air inlet (10) consists of a shrinking section and a cylinder. It is composed of segments. The meridian line of the contraction segment is a lemniscate or a 30-60° arc line. The diameter of the cylindrical segment is 2-6 mm and the length is 4-10 mm. Its center line is 5-15 mm away from the top of the probe. There are air outlets (6) on the left and right sides of the air port (10). The air outlet (6) is led from the leeward side of the probe support rod (9) and has a diameter of 0.1 to 2 mm; The temperature sensor (1) and the windward pressure pipe (2) are fixed in the mounting base (4) through insulating sealant (5). Their center lines are parallel to the direction of flow. The head of the temperature sensor (1) is far away from the probe. The windward side of the support rod (9) is 2 to 6 mm. The temperature sensor cable (8) leads out of the tail of the probe support rod (9) through the circular channel (7). 10) The front end is 1 to 4 mm, and the rear end leads to the tail of the probe rod (9) through the circular channel (7). The front end of the windward side pressure tube (2) is 1 to 3 mm longer than the front end of the temperature sensor (1); The leeward side pressure pipe (3) is fixed in the leeward side installation hole (11) through the insulating sealant (5). Its center line is collinear with the windward side pressure pipe (2). The leeward side pressure pipe (3) head The part is 1 to 4 mm away from the leeward side of the probe pole (9), and the tail is led out from the tail of the probe pole (9) through the circular channel (7); The circular channel (7) has a diameter of 2 to 6 mm, its center line is 0.5 to 5 mm away from the center line of the probe support rod (9), its top is flush with the upper end of the air inlet (10), and its lower end runs through the probe support rod. (9).