CN108414133B - The method of friction stree is measured under high temperature indirectly - Google Patents

The method of friction stree is measured under high temperature indirectly Download PDF

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Publication number
CN108414133B
CN108414133B CN201810124710.3A CN201810124710A CN108414133B CN 108414133 B CN108414133 B CN 108414133B CN 201810124710 A CN201810124710 A CN 201810124710A CN 108414133 B CN108414133 B CN 108414133B
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pressure
hole
flow field
survey
inclined hole
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CN108414133A (en
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孟松鹤
罗杨
易法军
许承海
解维华
金华
方国东
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Harbin Institute of Technology
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Harbin Institute of Technology
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01LMEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L13/00Devices or apparatus for measuring differences of two or more fluid pressure values
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N19/00Investigating materials by mechanical methods
    • G01N19/02Measuring coefficient of friction between materials

Abstract

The present invention relates to the pressure difference measuring devices for measuring friction stree under a kind of high temperature indirectly, including measuring head and differential pressure pickup, the measuring head, which is equipped with to survey straightening hole and survey, presses inclined hole, it is described survey straightening hole and it is described survey pressure inclined hole inlet end be connected to the flow field of part outer surface to be measured, two measurement portions of the differential pressure pickup measure respectively it is described survey straightening hole and it is described survey press inclined hole in air pressure;The measuring head is embedded at the part to be measured, end face where the inlet end for surveying straightening hole and the survey pressure inclined hole is flushed with the outer surface of the part to be measured, direction of flow of the line for surveying straightening hole and the inlet end for surveying pressure inclined hole perpendicular to the flow field, the survey pressure inclined direction of flow met to the flow field of inclined hole.The present invention also provides a kind of methods for measuring friction stree under high temperature indirectly.Pressure difference measuring device high temperature resistant provided by the invention, structure are simple, easy for installation, and stream field influences small, can be used in accurately measuring true skin friction stress.

Description

The method of friction stree is measured under high temperature indirectly
Technical field
The present invention relates to the methods for measuring friction stree under field of sensing technologies more particularly to high temperature indirectly.
Background technique
Friction stree is very big for flow field and in the object contributions of flow, is a key measurement target.It is logical Measurement pressure difference is crossed, friction stree can be calculated.But in extreme environment, such as under conditions of high temperature and high speed, measurement rubs The sensor for wiping strain gauge or measurement pressure difference can not normal use.And existing friction stree measuring device, no matter It is direct measuring device or indirect measurement system, usual volume is larger, and needs to be transformed part surface to be measured when installation, The surface shape for destroying part to be measured itself disturbs the distribution of part External airflow field to be measured, especially high in hypersonic high temperature Under fast environment, non-smooth surface can make flow field generate very big disturbance, so that skin friction stress measurement failure, while Aerodynamic Heating Tip, which concentrates will lead to, assembles a large amount of Aerodynamic Heating at friction stree sensor, may burn measuring device, or even burn to be measured Part surface.
Summary of the invention
(1) technical problems to be solved
The technical problem to be solved by the present invention is to solve existing friction stree measuring device not making in the high temperature environment With, and the problem of flow field can be disturbed, can not accurately measure true skin friction stress.
(2) technical solution
In order to solve the above-mentioned technical problems, the present invention provides the pressure difference measurements for measuring friction stree under a kind of high temperature indirectly Device, including measuring head and differential pressure pickup, the measuring head be equipped with survey straightening hole and survey pressure inclined hole, the surveys straightening hole with The inlet end for surveying pressure inclined hole is connected to the flow field of part outer surface to be measured, and two measurement portions of the differential pressure pickup are surveyed respectively Measure the survey straightening hole and the air pressure surveyed in pressure inclined hole;
The measuring head is embedded at the part to be measured, the end surveyed where straightening hole and the inlet end for surveying pressure inclined hole Face is flushed with the outer surface of the part to be measured, and the line for surveying straightening hole and the inlet end for surveying pressure inclined hole is perpendicular to described The inclined direction of flow met to the flow field of inclined hole is pressed in the direction of flow in flow field, the survey.
Preferably, the measuring head is made of metal or alloy resistant to high temperature.
Preferably, the pressure inclined hole and the direction of flow angular range in the flow field surveyed is 25 °~70 °.
Preferably, the minimum range range surveyed between straightening hole and the inlet end for surveying pressure inclined hole is 0~20mm; The straightening hole and the pressure inclined hole of surveying surveyed is the equal circular hole of diameter, and diameter range is 0.1~2mm;The survey straightening hole and The length range for surveying pressure inclined hole is 10~20mm.
It preferably, further include two pressure output connectors, two measurement portions of the differential pressure pickup pass through institute respectively Pressure output connector is stated to connect with the survey straightening hole and survey pressure inclined hole.
Preferably, described survey between straightening hole and the outlet side and the pressure output connector for surveying pressure inclined hole is equipped with Pressure connecting channels;The output end of the pressure connecting channels is equipped with sealing screw thread, the pressure output connector and the pressure Power interface channel is threadedly coupled.
Preferably, the measuring head is cylindrical metal part, described to survey straightening hole and the inlet end point for surveying pressure inclined hole The two sides in the cylindrical metal part center of circle are not set;It is additionally provided with flange mounting portion in the measuring head, is used for the survey Amount head is fixedly installed to the part to be measured.
The present invention also provides a kind of methods for measuring friction stree under high temperature indirectly, include the following steps:
The relational expression of friction stree at the surveyed pressure difference of pressure difference measuring device described in any of the above embodiments and its surveyed pressure difference Are as follows:
In relational expression: Δ P is pressure difference, and A and B are constant to be calibrated, τwFor friction stree, ρ is current density, and μ is power Viscosity, h are characterized height, are determined by the structure of the pressure difference measuring device,D is the diameter for surveying pressure inclined hole, θ For the angle surveyed between pressure inclined hole and the direction of flow in flow field;
The pressure difference measuring device is fitted into caliberating device, under the environment different in flow rate in calibration flow field, passes through institute It states caliberating device to demarcate the relational expression, obtains the relational expression of at least two A and B, solve the numerical value of A and B;
The calibrated pressure difference measuring device is mounted on part to be measured, measures pressure differential deltap P;It is measured and is filled using current density The current density ρ for measuring the flow field on the part surface to be measured is set, the part surface to be measured is measured using dynamic viscosity measuring device Flow field dynamic viscosity μ;
Pass through the relational expression:Solution obtains the friction stree on the part surface to be measured.
Preferably, the caliberating device includes flow field channel, pressure difference measuring device fixed part and multiple pitots;
The probe portion of multiple pitots protrudes into the flow field channel, meets the incoming flow side to the calibration flow field To for detecting the flow velocity in the calibration flow field;
The pressure difference measuring device is mounted on the side wall of the flow field channel by the pressure difference measuring device fixed part, And after mounting, the inner surface of the end face where the inlet end for surveying straightening hole and the survey pressure inclined hole and the flow field channel It flushes, the calibration surveyed between straightening hole and the inlet end and two pitots for surveying pressure inclined hole is connected with flow field Logical, straightening hole and the inlet end line for surveying pressure inclined hole surveyed is described perpendicular to the direction of flow in the calibration flow field Survey the pressure inclined direction of flow met to the flow field of inclined hole.
Preferably, the calibration flow field being located in the flow field channel is provided using wind-tunnel or blower;
The calibration is in control by the air speed and flows through the forward and backward flow velocity of the pressure difference measuring device with flow field, is calculated Obtain the friction stree at the surveyed pressure difference of pressure difference measuring device;
According to the obtained friction stree, pass through the surveyed pressure difference of pressure difference measuring device and rubbing at its surveyed pressure difference The relational expression for wiping stress, obtains the relational expression of A and B.
(3) beneficial effect
Above-mentioned technical proposal of the invention has the advantages that measures friction stree under high temperature provided by the invention indirectly Pressure difference measuring device structure is simple, is easily installed arrangement, it might even be possible to be arranged in the measuring system of pressure, to part surface to be measured Flow is small, and will not generate Aerodynamic Heating, can be used in accurately measuring true skin friction stress under high temperature.The present invention mentions The method for measuring friction stree indirectly at a high temperature of be utilized indirectly survey pressure measurement principle, can overcome differential pressure pickup without Method measures the problem of high temperature flow field, for accurately measuring true skin friction stress.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of measuring head in the embodiment of the present invention;
Fig. 2 is the line A-A sectional view in Fig. 1;
Fig. 3 is the line B-B sectional view in Fig. 1;
Fig. 4 is the structural schematic diagram of pressure output connector in the embodiment of the present invention;
Fig. 5 be measured indirectly under high temperature of the embodiment of the present invention friction stree pressure difference measuring device measuring head and pressure it is defeated After connector device is matched out, line A-A diagrammatic cross-section;
Fig. 6 be measured indirectly under high temperature of the embodiment of the present invention friction stree pressure difference measuring device measuring head and pressure it is defeated After connector device is matched out, line B-B diagrammatic cross-section;
Fig. 7 is that apparatus structure schematic diagram is demarcated in the embodiment of the present invention;
Fig. 8 is the line D-D sectional view in Fig. 7;
Fig. 9 is the top view of caliberating device in the embodiment of the present invention;
In figure: 1: measuring head;11: surveying pressure inclined hole;12: surveying straightening hole;13: sealing screw thread;14: pressure connecting channels;15: Mounting-positioning holes;2: pressure output connector;3: flow field channel;4: pitot;41: pitot guide pile;5: pressure difference measurement dress Set fixed part.
Specific embodiment
In order to make the object, technical scheme and advantages of the embodiment of the invention clearer, below in conjunction with the embodiment of the present invention In attached drawing, technical scheme in the embodiment of the invention is clearly and completely described, it is clear that described embodiment is A part of the embodiments of the present invention, instead of all the embodiments.Based on the embodiments of the present invention, ordinary skill people Member's every other embodiment obtained without making creative work, shall fall within the protection scope of the present invention.
The pressure difference measuring device for measuring friction stree under high temperature provided by the present invention indirectly is measured using indirect pressure-measuring type Friction stree, measuring principle are as follows: design two types pressure tap, one of them for survey straightening hole 12, measurement can to Survey part Surface Static Pressure, to survey pressure inclined hole 11, measurement can be obtained with the stagnation pressure centainly lost, be measured by differential pressure pickup for another The pressure difference of two pressure taps, measuring the friction stree of resulting pressure difference and measured place, there are corresponding relationships, for friction stree τw, Frictional resistance i.e. in unit area, τwThe corresponding relationship of pressure differential deltap P between two pressure taps are as follows:
Work as reynolds number RehWhen smaller, viscous force accounts for leading, Δ P ∝ τw
Work as reynolds number RehWhen larger, inertia force account for it is leading,
The relationship obtained between pressure difference and friction stree is expressed as:
Wherein, ρ is current density, and μ is dynamic viscosity, and current density and dynamic viscosity pass through the existing measurement of the prior art Device measures;H is characterized height, is determined by the structure of pressure difference measuring device,D is that inclined hole 11 is pressed in the survey Diameter, θ is the angle surveyed between pressure inclined hole 11 and the direction of flow in flow field, and A and B are constant to be calibrated, passes through calibration It determines.
After demarcating by caliberating device to pressure difference measuring device, A and B are obtained, establishes part skin friction stress to be measured With measure the true relation formula between resulting pressure difference, in conjunction with the current density in the flow field of current density measuring device measurement, The dynamic viscosity and pressure difference measuring device provided by the present invention in the flow field of dynamic viscosity measuring device measurement measure to be measured Part surface pressure difference solves and obtains true skin friction stress, final to realize under high temperature environment measurement friction stree indirectly Or frictional resistance.
As shown in Figures 1 to 6, the pressure difference measurement of friction stree is measured under a kind of high temperature provided in an embodiment of the present invention indirectly Device, including measuring head 1 and differential pressure pickup (not shown), measuring head 1, which is equipped with to survey straightening hole 12 and survey, presses inclined hole 11, The inlet end surveyed straightening hole 12 and survey pressure inclined hole 11 is connected to the flow field flowed along part outer surface to be measured, and two of differential pressure pickup Measurement portion is connected to the outlet side surveying straightening hole 12 and surveying in pressure inclined hole 11 respectively, i.e., measures straightening hole 12 respectively and survey pressure tiltedly Air pressure in hole 11.Differential pressure pickup in the present invention is for measuring pressure inclined hole 11 and surveying the pressure of the input of straightening hole 12 Difference does not further limit it at this.Obviously, in other embodiments, can also be surveyed respectively using two pressure sensors Measurement straightening hole 12 and the pressure for surveying the pressure input of inclined hole 11, then the pressure difference of the two is calculated, it can be realized two pressure taps of measurement The function of pressure difference.
Measuring head 1 is embedded at part to be measured, surveys straightening hole 12 and surveys the end face where the inlet end of pressure inclined hole 11 and part to be measured Outer surface flush, that is, the direction of flow in flow field be located at survey straightening hole 12 and survey pressure inclined hole 11 inlet end institute planar, keep away The shape for exempting from measuring head 1 interferes part surface flow field to be measured.
The pressure difference measuring device for measuring friction stree under high temperature provided by the present embodiment indirectly uses embedded inclined tube Structure will not generate pneumatic heated tip concentration phenomenon in use, therefore the pressure difference measuring device of the present embodiment can be used for It works in high temperature and high speed environment.Since measuring head 1 is directly connected to high temperature flow field, it is therefore preferred that measuring head 1 uses resistance to height The metal or alloy of temperature is made, such as stainless steel.
As shown in Figure 1 and Figure 5, the arrow in figure indicates the direction of flow in flow field, surveys straightening hole 12 and surveys pressure inclined hole 11 The line of inlet end surveys the pressure inclined direction of flow met to flow field of inclined hole 11, with flow field perpendicular to the direction of flow in flow field Direction of flow angular range is 25 °~70 °, preferably 60 °.
It is in same flow field state to guarantee to survey straightening hole 12 and surveying pressure inclined hole 11, improves measurement accuracy, two pressure taps Top between should keep lesser distance, and it is more closer better, but due to design upper two pressure taps can not infinite approach, Preferably, the minimum range range surveying straightening hole 12 and surveying between pressure 11 top of inclined hole is 0~20mm.
When the diameter of pressure tap is too small, sensitivity is lower, will affect the sensitivity of measurement;When pressure tap diameter is excessive When, pressure tap meeting interference flowing field influences the accuracy of measurement.For the sensitivity and accuracy for guaranteeing pressure difference measurements, straightening is surveyed Hole 12 is the equal circular hole of diameter with pressure inclined hole 11 is surveyed, and diameter range is 0.1~2mm, preferably 1mm.
The length of two pressure taps can also have an impact measurement accuracy, and the length of two pressure taps herein refers to surveying The length and survey pressure inclined hole 11 in straightening hole 12 are in the projected length surveyed on 12 direction of straightening hole.The too short meeting of the length of two pressure taps Stream field generates interference, too long to will lead to the oversized of measuring head 1, should not install, therefore, the length of two pressure taps is not answered Less than 10mm, preferably 10~20mm.
In order to avoid measuring head 1 to change the shape of part to be measured as far as possible, reduce alignment measurement head 1 to the surface radian of part to be measured Influence, and then reduce stream field caused by interfere, the area that measuring head 1 is contacted with flow field should be as small as possible, and 1 surface of measuring head Degree of roughness should be consistent with part surface to be measured.As shown in Figure 1 to Figure 3, specific in the present embodiment, measuring head 1 is cylinder Stainless steel metal part, diameter range are 20~30mm, preferably 20mm.The top surveyed straightening hole 12 and survey pressure inclined hole 11 is set respectively Set the two sides in the cylindrical metal part center of circle.Flange mounting portion is additionally provided in measuring head 1, flange installation position is in cylindrical metal The bottom of part is equipped with several mounting-positioning holes 15, for measuring head 1 to be fixedly installed to part to be measured, it is ensured that stream when installation Positional relationship between the direction of flow of field and survey straightening hole 12 and survey pressure inclined hole 11.The pass of measuring head 1 and flow field direction of flow System is as shown in Fig. 1, Fig. 5 and Fig. 6.
Specifically, which further includes two pressure output connectors 2, and measuring head 1 is connected by pressure output Measurement portion output pressure of the device 2 to differential pressure pickup is connect, the structure of pressure output connector 2 is as shown in Figure 4 and Figure 5.Pressure difference passes Two measurement portions of sensor (not shown), which pass through pressure output connector 2 respectively and survey straightening hole 12 and survey pressure inclined hole 11, to be connected It connects.
Preferably, it as shown in Fig. 2, Fig. 3, Fig. 5 and Fig. 6, surveys straightening hole 12 and surveys and press the outlet side of inclined hole 11 and pressure defeated Pressure connecting channels 14 are equipped between connector 2 out.Pressure inclined hole is surveyed in the input terminal of pressure connecting channels 14 and survey straightening hole 12 11 outlet side connection, output end are equipped with sealing screw thread 13, and pressure connecting channels 14 are threadedly coupled with pressure output connector 2, Guarantee to survey straightening hole 12 or survey the sealed connection of pressure inclined hole 11 and pressure output connector 2, makes pressure transmission access not by dry It disturbs.
In conclusion the pressure difference measuring device of friction stree, structure are measured under present embodiments providing a kind of high temperature indirectly Simply, easy for installation, it might even be possible to be arranged in the measuring system of pressure.In use, measuring head 1 is embedded in determinand, and it is to be measured The surface of object flushes, and the pressure tap in measuring head 1 avoids the interference to determinand surface flow field, Neng Gouyong by design In measuring true skin friction stress indirectly.
The present invention also provides a kind of methods for measuring friction stree under high temperature indirectly, include the following steps:
The relational expression of the friction stree at the surveyed pressure difference of pressure difference measuring device and its surveyed pressure difference in above-described embodiment are as follows:
In relational expression: Δ P is pressure difference, and A and B are constant to be calibrated, τwFor friction stree.ρ is current density, and μ is power Viscosity, both can be measured by measuring device in the prior art.H is characterized height, by the structure of pressure difference measuring device It determines,D is the diameter for surveying pressure inclined hole 11, and θ is the angle surveyed between pressure inclined hole 11 and the direction of flow in flow field.
The pressure difference measuring device is fitted into caliberating device, under the environment different in flow rate in calibration flow field, passes through institute It states caliberating device to demarcate the relational expression, obtains the relational expression of at least two A and B, solve the numerical value of A and B.
Calibrated pressure difference measuring device is mounted on part to be measured, pressure differential deltap P is measured;Using current density measuring device The current density ρ for measuring the flow field on part surface to be measured measures the dynamic of the flow field on part surface to be measured using dynamic viscosity measuring device Power viscosity, mu.
Preferably, the temperature and air pressure in the present embodiment by flow field be calculated the flow field on part surface to be measured air-flow it is close Spend ρ and dynamic viscosity μ.
The expression formula of current density are as follows:
Wherein, ρ is current density, and P is air pressure, and T is temperature, and R is gas constant, the R=287J/kgK of air.I.e. originally Current density measuring device in embodiment includes temperature measuring equipment.The optional pyrometer of temperature measuring equipment, thermal imaging system or thermocouple etc. are surveyed Optional pressure sensor of pneumatic shuttle etc..
Dynamic viscosity is the parameter of temperature and gaseous species, and the relational expression of dynamic viscosity can be expressed as:
Wherein, μ0Dynamic viscosity when being 15 DEG C, μ0=1.7894e-5, B is constant related with gaseous species, air B=110.4K.Dynamic viscosity measuring device i.e. in the present embodiment includes measuring device and surveys pneumatic shuttle, wherein temperature measuring equipment Optional pyrometer, thermal imaging system or thermocouple etc..
Current density measuring device and dynamic viscosity measuring device in the present embodiment can share temperature measuring equipment, that is, pass through survey Warm device and survey pneumatic shuttle, that is, can measure the current density ρ and dynamic viscosity μ in the flow field on part surface to be measured.Certainly, at other In embodiment, current density ρ and dynamic viscosity μ can also be measured using other modes.
Pass through relational expression:Above-mentioned parameters are brought into relational expression and are solved, can be obtained The friction stree on part surface to be measured.
As shown in Figure 7 to 9, caliberating device used in the present embodiment includes that flow field channel 3, pressure difference measuring device are fixed Portion 5 and multiple pitots 4.Arrow in figure indicates the flowing in flow field, i.e. direction of flow.The probe portion of multiple pitots 4 is stretched Enter in flow field channel 3, meet the direction of flow to calibration flow field, for detecting the flow velocity in calibration flow field.
Pressure difference measuring device to be calibrated is mounted on the side wall of flow field channel 3 by pressure difference measuring device fixed part 5, and After mounting, the end face where surveying straightening hole 12 and surveying the inlet end of pressure inclined hole 11 is flushed with the inner surface of flow field channel 3, surveys pressure Straight hole 12 and the inlet end for surveying pressure inclined hole 11 are connected to the calibration between two pitots 4 with flow field, i.e., the institute of each pitot 4 The calibration flow field range of measurement should cover the calibration the surveyed flow field range at measuring head 1.In other words, at least one air speed Pipe 4 measures the calibration flow field for not flowing through measuring head 1, and the measurement of at least one pitot 4 flows through the calibration stream after measuring head 1 , accurate flow field data are provided for calibration.It surveys straightening hole 12 and surveys the inlet end line of pressure inclined hole 11 perpendicular to calibration stream The direction of flow of field surveys the pressure inclined direction of flow met to flow field of inclined hole 11.
Preferably, flow field channel 3 is made of material identical with measuring head 1, the roughness and measuring head 1 of inner surface Roughness it is consistent.Specific in the present embodiment, flow field channel 3 is made of stainless steel structure, and longitudinal section is square, Ke Yishi For various extreme flow fields environments, be able to bear higher temperature and stronger disturbance, be unlikely to deform, and with institute in the present embodiment 1 material of measuring head is identical, is applicable to the calibration environment of high temperature.Flow field channel 3 is welded by the stainless steel plate by polishing Connection, weld smooth welding joint impulse- free robustness avoid interfering calibration with flow field.
As shown in Figure 7 and Figure 8, specific in the present embodiment, 4 small size L-type pitots 4 pass through pitot guide pile 41 are fixed on a side of flow field channel 3, and the probe portion of pitot 4 protrudes into the depth of flow field channel 3 along calibration stream The direction of flow of field successively increases, it is ensured that the pitot 4 for first touching calibration flow field does not interfere with posterior pitot 4 and surveys Amount, avoids interfering with each other between each pitot 4, influences the flowing in calibration flow field.Preferably, adjacent in 4 pitots 4 The distance of two pitots 4 is equal.
The flow velocity that calibration flow field is measured by multiple pitots 4, calibration is simulated with flow field flow line speed, can True flow field velocity change curve is obtained, more accurately to calculate friction stree.Obviously, in other embodiments, It can according to need the number for changing pitot 4.
Specific in the present embodiment, pressure difference measuring device fixed part 5 is in the plane on the side wall adjacent with pitot 4 Heart district domain, including measuring head guide pile and 4 positioning bolts.Measuring head guide pile is hollow structure, and end and flow field channel 3 connect Logical, the top of measuring head guide pile is arranged in positioning bolt.When installation, measuring head 1 is inserted into measuring head guide pile, with calibration stream Connection, positioning bolt is inserted into mounting-positioning holes 15 in measuring head 1, and measuring head 1 is fixed, and when installation should guarantee measuring head 1 simultaneously With the positional relationship of flow field channel 3 and two positional relationships between pressure tap and direction of flow.
By measurement temperature and pressure in the present embodiment, gas density and dynamic viscosity are measured indirectly, it is preferable that calibration dress Setting further includes temperature measuring equipment and survey pneumatic shuttle, and both of which is the prior art.And due to the flow field for same state, air-flow Density and dynamic viscosity belong to stable atmospheric parameter, and temperature measuring equipment and survey pneumatic shuttle can be set in the outside of flow field channel 3.
In the present embodiment, when the above-mentioned caliberating device of pressure difference measuring device loading to be calibrated is demarcated, using wind-tunnel Or blower provides the calibration flow field being located in flow field channel 3, calibration flow field is steady flow field.It is marked by pitot 4 It is fixed to flow through the forward and backward flow velocity of pressure difference measuring device to be calibrated with flow field, it is calculated at the surveyed pressure difference of pressure difference measuring device Friction stree.
Specifically, it when solving friction stree, can be calculated according to the formula of theorem of kinetic energy and friction working.First really The flow field velocity that calibration is changed with flow field along grain direction surely, then calculates 3 surface of flow rate attenuation and flow field channel of this section The acting of the relationship of frictional resistance, i.e. frictional resistance causes the flow field velocity in calibration flow field to reduce, and finally obtains this section of flow field The frictional resistance curve in channel 3, friction stree are the frictional resistance on unit area.
According to obtained friction stree, pass through the friction stree at the surveyed pressure difference of pressure difference measuring device and its surveyed pressure difference Relational expression obtains the relational expression of A and B.The relational expression for obtaining two A and B solves A's and B using linear equation in two unknowns group Numerical value.
Preferably, after the numerical value that A and B can also be solved again, third A and B are obtained with flow field by calibration different in flow rate Relational expression, bring into and checked by the surveyed pressure difference of pressure difference measuring device and the friction stree at its surveyed pressure difference.
In the relationship of mark Timing measurement multiple groups friction stree and pressure difference, the function curve of friction stree and pressure difference can be obtained, By the relational expression of surveyed pressure difference and the friction stree of its surveyed pressure difference it is found that the function curve is through zero crossing, and solves section and lead Number is positive.Therefore, it when solving friction stree, takes by the ascending power section of (0,0) point in curve, and in first interval Solution.
Finally, it should be noted that the above embodiments are merely illustrative of the technical solutions of the present invention, rather than its limitations;Although Present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that: it still may be used To modify the technical solutions described in the foregoing embodiments or equivalent replacement of some of the technical features; And these are modified or replaceed, technical solution of various embodiments of the present invention that it does not separate the essence of the corresponding technical solution spirit and Range.

Claims (8)

1. the method for friction stree is measured under a kind of high temperature indirectly, it is characterised in that:
It is measured using pressure difference measuring device, the pressure difference measuring device includes measuring head and differential pressure pickup, the measurement Head, which is equipped with, surveys straightening hole and survey pressure inclined hole, described to survey straightening hole and the inlet end for surveying pressure inclined hole and part outer surface to be measured Flow field connection, two measurement portions of the differential pressure pickup measure the survey straightening hole and the gas surveyed in pressure inclined hole respectively Pressure;
The measuring head is embedded at the part to be measured, the end face surveyed where straightening hole and the inlet end for surveying pressure inclined hole with The outer surface of the part to be measured flushes, and the line for surveying straightening hole and the inlet end for surveying pressure inclined hole is perpendicular to the flow field Direction of flow, the survey presses the inclined direction of flow met to the flow field of inclined hole;
Measurement includes the following steps:
The relational expression of friction stree at the surveyed pressure difference of pressure difference measuring device and its surveyed pressure difference are as follows:
In relational expression: Δ P is pressure difference, and A and B are constant to be calibrated, τwFor friction stree, ρ is current density, and μ is dynamic viscosity, h It is characterized height, is determined by the structure of the pressure difference measuring device,D is the diameter for surveying pressure inclined hole, and θ is institute State the angle surveyed between pressure inclined hole and the direction of flow in flow field;
The pressure difference measuring device is fitted into caliberating device, under the environment different in flow rate in calibration flow field, passes through the mark Determine device to demarcate the relational expression, obtain the relational expression of at least two A and B, solves the numerical value of A and B;
The calibrated pressure difference measuring device is mounted on part to be measured, measures pressure differential deltap P;It is surveyed using current density measuring device The current density ρ for measuring the flow field on the part surface to be measured measures the stream on the part surface to be measured using dynamic viscosity measuring device The dynamic viscosity μ of field;
Pass through the relational expression:Solution obtains the friction stree on the part surface to be measured.
2. the method for friction stree is measured under high temperature according to claim 1 indirectly, it is characterised in that: the pressure difference measurement The measuring head of device is made of metal or alloy resistant to high temperature.
3. the method for friction stree is measured under high temperature according to claim 1 indirectly, it is characterised in that: the pressure difference measurement The survey pressure inclined hole of device and the direction of flow angular range in the flow field are 25 °~70 °.
4. the method for friction stree is measured under high temperature according to claim 1 indirectly, it is characterised in that: the pressure difference measurement Minimum range range between the survey straightening hole of device and the inlet end for surveying pressure inclined hole is 0~20mm;The survey pressure Straight hole and the pressure inclined hole of surveying are the equal circular hole of diameter, and diameter range is 0.1~2mm;The survey straightening hole and survey pressure The length range of inclined hole is 10~20mm.
5. the method for friction stree is measured under high temperature according to claim 1 indirectly, it is characterised in that: the pressure difference measurement Device further includes two pressure output connectors, and two measurement portions of the differential pressure pickup are connected by the pressure output respectively Device is connect to connect with the survey straightening hole and survey pressure inclined hole.
6. the method for friction stree is measured under high temperature according to claim 5 indirectly, it is characterised in that: the pressure difference measurement Press-in connection is equipped between the survey straightening hole of device and the outlet side and the pressure output connector for surveying pressure inclined hole Channel;The output end of the pressure connecting channels is equipped with sealing screw thread, and the pressure output connector and the press-in connection are logical Road is threadedly coupled.
7. the method for friction stree is measured under high temperature according to claim 1 indirectly, it is characterised in that: the pressure difference measurement The measuring head of device is cylindrical metal part, and the survey straightening hole and the inlet end for surveying pressure inclined hole are separately positioned on institute State the two sides in the cylindrical metal part center of circle;It is additionally provided with flange mounting portion in the measuring head, pacifies for fixing the measuring head It is attached to the part to be measured.
8. the method for friction stree is measured under high temperature according to any one of claims 1 to 7 indirectly, it is characterised in that:
The caliberating device includes flow field channel, pressure difference measuring device fixed part and multiple pitots;
The probe portion of multiple pitots protrudes into the flow field channel, meets the direction of flow to the calibration flow field, For detecting the flow velocity in the calibration flow field;
The pressure difference measuring device is mounted on the side wall of the flow field channel by the pressure difference measuring device fixed part, and After installation, the inner surface for surveying end face and the flow field channel where straightening hole and the inlet end for surveying pressure inclined hole is neat Flat, the calibration surveyed between straightening hole and the inlet end and two pitots for surveying pressure inclined hole is connected with flow field Logical, straightening hole and the inlet end line for surveying pressure inclined hole surveyed is described perpendicular to the direction of flow in the calibration flow field Survey the pressure inclined direction of flow met to the flow field of inclined hole.
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