Background
Under various total temperature test conditions, different types of total temperature probes are needed to measure the total temperature of the flow field. The key of accurately measuring the total temperature of the airflow is whether the airflow can be rapidly stagnant at a temperature measuring point and the rapid heat exchange of the gas in the stagnation cover is ensured.
Most of the existing total temperature probes are front hole air inlet and two side holes or rear hole air exhaust, and have the defects of large axial size, small insensitive angle of air flow, incapability of fully stagnating the air flow in a stagnating cover when the pitch angle or deflection angle of incoming flow to be detected is large, and large total temperature measurement error. The armored thermocouple has slow reaction and low frequency response.
The total temperature of the airflow at the outlet of the rotor of the centrifugal compressor is measured, and the total temperature probe is required to be small in axial size and large in airflow insensitivity angle due to small blade row gaps and large inflow angles.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: aiming at the problems of the conventional total temperature probe, the invention provides a porous adjacent total temperature probe which can accurately measure the total temperature of a flow field with small blade row gap and large inflow angle at the rotor outlet of a centrifugal compressor and has the characteristics of small head size of a temperature measuring part and large insensitive angle of airflow.
The technical solution of the invention is as follows:
1. the utility model provides a porous total warm probe of next-door neighbour, by stagnation cover (1), convection heat transfer hole (2), temperature sensor (3), probe branch (4), adiabatic sealing member (5), adiabatic sealed lid (6) and temperature measurement lead wire (7) constitute its characterized in that: the stagnation cover (1) is made of nickel-based alloy materials, one end of the stagnation cover is sealed, the other end of the stagnation cover is connected with the probe supporting rod (4), 3-5 convection heat exchange holes are formed in the stagnation cover (1) along the axial direction or the circumferential direction, and the degree of finish of the outer surface of the stagnation cover is not lower than 3.2 microns.
2. Further, convection heat transfer hole (2) are circular, and the hole diameter is 2 millimeters to 4 millimeters, and it has 3 convection heat transfer holes (2) to open on stagnant cover (1), and convection heat transfer hole (2) can be followed the axial distribution of stagnant cover (1), also can be followed the circumference distribution of stagnant cover (1), and to opening 5 convection heat transfer holes (2) on stagnant cover (1), the convection heat transfer hole is followed stagnant cover (1) axial and circumference and is distributed. The central line of the middle convection heat exchange hole (2) is vertical to the axis of the stagnation cover (1), the central lines of the upper and lower or left and right convection heat exchange holes (2) and the central line of the middle convection heat exchange hole (2) are on a plane and can be intersected at a point, the included angles of the central lines of the two convection heat exchange holes (2) and the central line of the middle convection heat exchange hole (2) are the same, the range is 30-60 degrees, and the spacing distance of the central lines of the adjacent convection heat exchange holes (2) along the surface of the stagnation cover (1) is 1.1-3 times of the diameter of the small hole.
3. Furthermore, the probe supporting rod (4) is supported by high-temperature-resistant alloy and is in an L shape or a straight rod shape. When the probe supporting rod (4) is L-shaped, holes with the diameter of 6 mm to 12 mm are formed in the corners of the L-shaped supporting rod and are sealed by the heat-insulating sealing cover (6), and the heat-insulating sealing cover (6) can be opened and used for replacing the temperature sensor (3). The surface finish is not less than 3.2 microns.
4. Further, the heat insulation sealing piece (5) is made of a ceramic material and is a hollow cylinder, the outer diameter of the heat insulation sealing piece is the same as the inner diameter of the probe supporting rod (4), the heat insulation sealing piece is pasted and fixed at one end of the probe supporting rod (4) through an adhesive, a through hole is formed in the middle of the heat insulation sealing piece, the diameter of the through hole is the same as that of the temperature sensor (3), and the temperature sensor (3) is pasted and fixed.
5. Furthermore, the temperature sensor (3) can be various thermocouples or thermal resistors, the axial position of the head of the sensor corresponds to the convection heat transfer hole (3) in the middle of the stagnation cover (1), and the temperature measurement lead (7) is led out through the tail of the probe support rod (4).
The invention has the advantages and positive effects that:
compared with the traditional total temperature probe, the porous adjacent total temperature probe has the advantages that the diameter of the convection heat exchange holes (2) on the stagnation cover (1) of the probe is larger, the convection heat exchange holes (2) on the two sides are obliquely opened, so that the total temperature probe has a larger air flow insensitive angle, and the total temperature of incoming flow is accurately measured under the condition that the deflection angle or pitch angle of the probe is larger.
The axial direction of the temperature measurement part of the temperature sensor (3) is over against the middle convection heat exchange hole (2), so that the rapid heat exchange of the air flow at the temperature measurement part of the sensor is ensured, and meanwhile, a thermocouple with a smaller time constant can be selected, so that the probe frequency response can be improved.
The heat insulation sealing piece (5) is used for fixing the temperature sensor (3), heat transfer and heat conduction errors can be reduced, the heat insulation sealing cover (6) can be opened, and the temperature sensor (3) is convenient to replace.
The probe has small size of the temperature measuring part and can be applied to a measuring area with narrow space. The method can accurately measure the total temperature of the flow field with small blade row clearance at the outlet of the centrifugal compressor rotor and large change of the incoming flow angle.
Detailed Description
The invention is further described below with reference to the accompanying drawings:
as shown in figure 1, the porous close-to-total temperature measurement probe comprises a stagnation cover (1), a convection heat transfer hole (2), a temperature sensor (3), a probe support rod (4), a heat insulation sealing piece (5), a heat insulation sealing cover (6) and a temperature measurement lead (7), wherein the stagnation cover (1) is connected with the probe support rod (5), the diameter of the stagnation cover (1) is 3 mm, and the wall thickness of the stagnation cover is 0.3 mm.
The stagnation cover (1) is provided with 3 convection heat exchange holes (2), the holes are circular, the diameters of the convection heat exchange holes (2) are 3 mm, the convection heat exchange holes (2) are distributed along the axial direction of the stagnation cover (1), the central line of the middle convection heat exchange hole (2) is vertical to the axis of the stagnation cover (1), the central lines of the convection heat exchange holes (2) at two sides and the central line of the middle convection heat exchange hole (2) are on the same plane and can be intersected at one point, the included angles of the central lines of the convection heat exchange holes (2) at two sides and the central line of the middle convection heat exchange hole (2) are the same and are 40 degrees, and the interval distance of the central lines of the adjacent convection heat exchange holes (2) is 6 mm along the surface of the stagnation cover (1).
The probe supporting rod (4) is L-shaped, the cross section of the probe supporting rod is circular, the diameter of the probe supporting rod is 8 mm, the wall thickness of the probe supporting rod is 2 mm, and the heat insulation sealing element (5) is fixed in the probe supporting rod (4). The temperature sensor (3) is fixed on the heat insulation sealing element (5), the temperature sensor (3) is positioned on the axis of the stagnation cover (1), the axial position of the temperature measuring end of the temperature sensor corresponds to the convection heat transfer hole (2) in the middle of the stagnation cover (1), and the temperature measuring lead (7) is led out through the tail part of the probe supporting rod (4).
The porous adjacent total temperature probe provided by the embodiment of the invention can accurately measure the total temperature of incoming flow under the condition of a larger deflection angle or pitch angle, and is suitable for measuring the total temperature of a flow field with small blade row clearance and larger change of the incoming flow angle at the rotor outlet of a centrifugal compressor.