CN102928615B - Measuring method of flow speed at nozzle of water-jet propulsor in sailing - Google Patents

Abstract

The invention discloses a measuring method of a flow speed at a nozzle of a water-jet propulsor in sailing. A dynamic pressure sensor and a gas content senor are installed on a platform where the water-jet propulsor is arranged. A sailing speed measuring instrument is fixed on the platform and the measuring method comprises towing post steps for confirming dynamic pressure large coefficients, drag steps for confirming influence of platform movement coefficients and sailing measurement steps for confirming the flow speed at the nozzle of the water-jet propulsor in sailing. The towing post steps are used for confirming the dynamic pressure large coefficients, the drag steps are used for confirming the influence of platform movement coefficients and the sailing measurement steps are used for confirming the flow speed at the nozzle. The measuring method of the flow speed at the nozzle of the water-jet propulsor in sailing can accurately measure the flow speed at the nozzle of the water-jet propulsor in sailing and is explicit in principle, clear in steps, quite explicit in measuring methods of all measured values and easy to achieve.

Description

The measuring method of the spout flow velocity of hydraulic propeller in a kind of navigation

Technical field

Flow rate of water flow fields of measurement of the present invention, is specifically related to the measuring method of the spout flow velocity of hydraulic propeller in a kind of navigation.

Background technology

Hydraulic propeller is a kind of propulsion system of motor platform waterborne, and spout flow velocity is an important indicator weighing hydraulic propeller serviceability.Under real navigation operating mode, in hydraulic propeller water spray, conventionally contain gas, the water spray flow velocity of spout also very large, vibration is also very strong, be subject to the restriction of these conditions, hydraulic propeller spout flow velocity (being the water spray flow velocity of spout) in navigation is not carried out to the method for effectively measuring at present, there is larger deviation in measurement result, therefore, seeks that a kind of can to carry out the method effectively measured to hydraulic propeller spout flow velocity in navigation very necessary.

Summary of the invention

The object of this invention is to provide a kind of method that can carry out effective measurement to the spout flow velocity of hydraulic propeller in navigation.

The technical solution used in the present invention is: the measuring method of the spout flow velocity of hydraulic propeller in a kind of navigation, dynamic pressure transducer and air content sensor are installed on the platform at hydraulic propeller place by installation of sensors pedestal, make dynamic pressure transducer and air content sensor be positioned at the dead ahead of the spout of hydraulic propeller; Speed of a ship or plane measuring instrument is fixed on described platform, in order to measure the speed of a ship or plane of described platform, described measuring method comprises for the towing post step of definite dynamic pressure factor beta bigger than normal, for determining the dilatory step of platform motion effects coefficient ξ and the spout flow velocity V for definite navigation hydraulic propeller _pnavigation determination step, wherein,

Described towing post step is: towing post is fixed on the bank, and one end of towing post rope is tethered on described towing post, and the other end is bolted on the platform at hydraulic propeller place, and described towing post rope is in series with the tautness meter for measuring towing post pulling force;

While implementing towing post, start hydraulic propeller, obtain by tautness meter the pulling force f that hydraulic propeller produces in the time spraying current on towing post rope 212, unit is N; Obtain the first spout current dynamic pressure P of hydraulic propeller by described dynamic pressure transducer ₁, unit is Pa;

Described dynamic pressure coefficient bigger than normal $\mathrm{\β}=\frac{f\cos \mathrm{\α}}{2{\mathrm{SP}}_1},$

Wherein, α is the horizontal sextant angle between towing post rope and surface level, and unit is degree; S is the area of injection orifice of hydraulic propeller, and unit is m ²;

Described dilatory step is: one end of a dilatory rope is tethered on described platform, and the other end is tethered on dilatory propulsion system;

While implementing to draw, close hydraulic propeller, start dilatory propulsion system, pull described platform motion by dilatory propulsion system, and obtain the second spout current dynamic pressure P of hydraulic propeller by described dynamic pressure transducer ₂, unit is Pa; Obtain the first spout current air content ρ of hydraulic propeller by described air content sensor ₁, unit is %; Obtain the first speed of a ship or plane V of hydraulic propeller place platform by described speed of a ship or plane measuring instrument _h1, unit is m/s;

Pass through

determine platform motion effects coefficient ξ, wherein, ρ _mthe hydrostatic density of place medium during for described platform motion, unit is kg/m ³;

Described navigation determination step is: start hydraulic propeller, make hydraulic propeller drive place platform motion, obtain the 3rd spout current dynamic pressure P of hydraulic propeller by described dynamic pressure transducer ₃, unit is Pa; Obtain the second spout current air content ρ of hydraulic propeller by described air content sensor ₂, unit is %; Obtain the second speed of a ship or plane V of hydraulic propeller place platform by speed of a ship or plane measuring instrument _h2, unit is m/s;

Pass through

determine spout flow velocity V _p, the unit of spout flow velocity is m/s.

Wherein, described dynamic pressure transducer and air content sensor are all installed on the position of dead ahead 70mm～80mm that is positioned at spout.

Wherein, described tautness meter, dynamic pressure transducer, air content sensor and speed of a ship or plane measuring instrument and process computer communication connection, so that the signal collecting is transferred to process computer, to obtain the spout flow velocity of dynamic pressure coefficient bigger than normal, platform motion effects coefficient and hydraulic propeller by process computer.

Wherein, the Check processing method of described air content sensor is:

Step 1: the potential electrode of measuring bridge is placed in to measured medium, and wherein, described measuring bridge comprises that resistance value is R _sbridge resistor and described potential electrode, the audible communication signal of positive and negative constant amplitude is inputed to the two ends of the series circuit that described potential electrode and bridge resistor form, wherein, the two ends of potential electrode are as the output terminal output polar plate voltage of measuring bridge;

Step 2: the effective value E that obtains audible communication signal _veffective value E with the polar plate voltage of potential electrode _i;

Step 3: obtain the resistance value R between potential electrode _i, wherein,

the corresponding potential electrode of i=p is placed in the detection limit of described measured medium, and the corresponding potential electrode of i=0 is placed in the detection limit of gas-free described measured medium;

Step 4: the interelectrode current air content of computation and measurement ρ, wherein,

wherein, current air content ρ is volumetric concentration;

Described air content sensor obtains the first spout current air content ρ of the residing flow field of potential electrode environment in dilatory step according to described Check processing method ₁, and obtain the second spout current air content ρ of the residing flow field of potential electrode environment in navigation determination step ₂.

Wherein, in step 2, obtain the effective value E of described audible communication signal by driving source RMS-DC converter circuit _v, obtain the effective value E of described polar plate voltage by electrode RMS-DC converter circuit _i; In step 2, the effective value E of audible communication signal _vbe converted to driving source standard current signal I through driving source change-over circuit _v, the effective value E of polar plate voltage _ibe converted to pole plate standard current signal I through electrode converting circuit _i, wherein, driving source change-over circuit is identical with the conversion coefficient of electrode converting circuit;

Described air content sensor is by its data acquisition process unit execution step 3 and 4, and described driving source standard current signal inputs in data acquisition process unit through driving source current signal isolation module, pole plate standard current signal I _iinput to data acquisition process unit through electrode current signal isolation module; Described data acquisition unit basis

computation and measurement electrode is placed in the resistance value R of described measured medium _pand potential electrode is placed in the resistance value R of gas-free described measured medium ₀.

Wherein, the amplitude of described audible communication signal is ± 12V～± 18V that frequency is 1500Hz～3000Hz.

Beneficial effect of the present invention is: measuring method of the present invention can accurately be measured hydraulic propeller spout flow velocity in navigation process, and measuring method principle of the present invention is clear and definite, and step is clear, and the method for testing of each measured value is also very clear and definite, is easy to realize; In addition, the Check processing method of air content sensor of the present invention, owing to having adopted the audible communication signal of positive and negative constant amplitude as driving source, effectively solves the problem of electrode surface polarization and calcification; In addition, adopt the effective value of audible communication signal and polar plate voltage as detection limit, simplified the complicacy of detecting signal unit, improved the reliability of circuit; Moreover measuring-signal converts current signal to by electric current and voltage converting unit, and after isolating, send data acquisition process unit to, improved the antijamming capability under the severe electromagnetic environment of system.

Accompanying drawing explanation

Fig. 1 is a kind of theory diagram of implementing structure according to air content sensor of the present invention;

Fig. 2 is the circuit theory diagrams of measuring bridge shown in Fig. 1;

Fig. 3 is the circuit structure in the audio excitation source shown in Fig. 1;

Fig. 4 is the circuit structure of detecting signal unit shown in Fig. 1 and electric current and voltage converting unit;

Fig. 5 is the workflow schematic diagram of data acquisition process unit shown in Fig. 1;

Fig. 6 is the enforcement structure of implementing towing post step of the present invention;

Fig. 7 is the enforcement structure of implementing dilatory step of the present invention;

Fig. 8 is the enforcement structure of implementing described navigation determination step of the present invention;

Fig. 9 shows according to the FB(flow block) of a kind of embodiment of the measuring method of spout flow velocity of the present invention.

Embodiment

While carrying out the measuring method of spout flow velocity of hydraulic propeller in navigation of the present invention, as shown in Fig. 6,7 and 8, dynamic pressure transducer 201 and air content sensor 202 are installed on by installation of sensors pedestal 203 on the platform 210 at hydraulic propeller place, the dead ahead that makes dynamic pressure transducer 201 and air content sensor 202 be positioned at the spout 209 of hydraulic propeller is for example on the position of 70mm～80mm, and this position can obtain more effective measurement data; Speed of a ship or plane measuring instrument 207 is fixed on platform 210, in order to the speed of a ship or plane of measuring table.

Measuring method of the present invention comprises for the towing post step of definite dynamic pressure factor beta bigger than normal, for determining the dilatory step of platform motion effects coefficient ξ and the spout flow velocity V for definite navigation hydraulic propeller _pnavigation determination step.

As shown in Figure 6, described towing post step is: towing post 211 is fixed on the bank, one end of towing post rope 212 (the present embodiment employing wire rope) is tethered on towing post 211, the other end is bolted on the platform 210 at hydraulic propeller place, and towing post rope 212 is in series with the tautness meter 213 for measuring towing post pulling force; While implementing towing post, start hydraulic propeller, obtain by tautness meter 213 the pulling force f that hydraulic propeller produces in the time spraying current on towing post rope, unit is N (newton); Obtain the first spout current dynamic pressure P of hydraulic propeller in towing post step by dynamic pressure transducer 201 ₁(being the dynamic pressure of nozzle current), unit is Pa.

Described dynamic pressure coefficient bigger than normal

wherein, α is the horizontal sextant angle between towing post rope and surface level, and unit is degree, and this horizontal sextant angle can obtain by throughput hornwork 215; S is the area of injection orifice of hydraulic propeller, and unit is m ².

This dynamic pressure coefficient bigger than normal refers to while utilizing the spout current dynamic pressure of hydraulic propeller to measure spout flow velocity, need to compress into the coefficient that row is revised to spout water flow.

As shown in Figure 7, described dilatory step is: be for example that one end of the dilatory rope 223 of wire rope is tethered on described platform by one, the other end is tethered on dilatory propulsion system 221; While implementing to draw, close hydraulic propeller, start dilatory propulsion system 221, pull described platform 210 to move by dilatory propulsion system 221, and obtain the second spout current dynamic pressure P of hydraulic propeller by dynamic pressure transducer 201 ₂, unit is Pa; Obtain the first spout current air content (being the air content of nozzle current) ρ of hydraulic propeller by air content sensor 202 ₁, unit is %; Obtain the first speed of a ship or plane V of hydraulic propeller place platform 210 by speed of a ship or plane measuring instrument 207 _h1, unit is m/s.

Pass through

determine platform motion effects coefficient ξ, wherein, ρ _mthe hydrostatic density of place medium during for described platform motion, unit is kg/m ³hydrostatic density refers to the natural density in platform place medium (the present embodiment is to measure in lake), with respect to the Media density of hydraulic propeller ejection, also can be described as without the Media density under External force interference, hydrostatic density can adopt common densitometer measurement to obtain.When described platform motion effects coefficient refers to the platform motion of hydraulic propeller place, the additional dynamic pressure that the nozzle current of hydraulic propeller are produced, while utilizing dynamic pressure measurement water spray flow velocity, need to carry out to dynamic pressure measurement value the coefficient of platform Motion correction.

As shown in Figure 8, described navigation determination step is: start hydraulic propeller, make hydraulic propeller drive place platform 210 to move, obtain the 3rd spout current dynamic pressure P of hydraulic propeller by dynamic pressure transducer 201 ₃, unit is Pa; Obtain the second spout current air content ρ of hydraulic propeller by air content sensor 202 ₂, unit is %; Obtain the second speed of a ship or plane V of hydraulic propeller place platform by speed of a ship or plane measuring instrument 207 _h2, unit is m/s.

Pass through $P_3\mathrm{\β}=\frac{1}{2}(1-{\mathrm{\ρ}}_2){\mathrm{\ρ}}_m{(V_P+\mathrm{\ξ}{V}_{h2})}^2$ Determine spout flow velocity V _p.

Above dynamic pressure transducer 201 can pass through dynamic pressure transducer electric signal interface 201a, air content sensor 202 can pass through air content sensor electrical signaling interface 202a, speed of a ship or plane measuring instrument 207 can pass through speed of a ship or plane measuring instrument electric signal interface 207a, tautness meter 213 can be transferred to the signal collecting in process computer 230 and process by tautness meter electric signal interface 213a, to obtain the spout flow velocity of dynamic pressure coefficient bigger than normal, platform motion effects coefficient and hydraulic propeller by process computer 230.Above horizontal sextant angle and area of injection orifice can input in process computer by the input media of process computer.

Fig. 9 shows the signal that towing post step, dilatory step and navigation determination step need to be measured, and relation between each step.

As shown in Figure 1, air content sensor of the present invention can comprise audio excitation source 1, measuring bridge 2, detecting signal unit 3 and data acquisition process unit 6, and wherein, as shown in Figure 2, measuring bridge 1 comprises that resistance value is R _sbridge resistor and for insert flow field carry out detect potential electrode, the input end that the two ends of the series circuit that potential electrode and bridge resistor form are measuring bridge, for inputting the audible communication signal of the positive and negative constant amplitude that audio excitation source 1 provides, the two ends of potential electrode are the output terminal of measuring bridge, for exporting polar plate voltage.Above audible communication signal can adopt amplitude to be ± 12V～± 18V, the sound signal that frequency is 1500Hz～3000Hz, and the amplitude of the audible communication signal that the present embodiment adopts is ± 15V that frequency is 3000Hz.

This detecting signal unit 3 comprises driving source RMS-DC converter circuit 31 and electrode RMS-DC converter circuit 32, and wherein, driving source RMS-DC converter circuit 31 is for calculating the effective value E of audible communication signal _v, electrode RMS-DC converter circuit 32 is for calculating the effective value E of polar plate voltage _i.This detecting signal unit carries out real-time synchronous detection to audible communication signal and polar plate voltage, although detection signal is a high frequency alternating signal, but the natural frequency of its tested object is not high, generally only have tens hertz, therefore, in circuit, adopt effective value as measured value, can not only meet actual requirement, can also simplify the complicacy of circuit, improve the reliability of system.

This data acquisition process unit 6 is receiving after the effective value of audible communication signal and the effective value of polar plate voltage, according to the interelectrode resistance value R of formula (1) computation and measurement _i, calculate the current air content C between the potential electrode that is placed in measured medium according to formula (2).

Formula (1):

wherein, the corresponding potential electrode of i=p is placed in each detection limit of described measured medium, and the corresponding potential electrode of i=0 is placed in the detection limit of gas-free described measured medium, i.e. R _pand E _pbe respectively potential electrode and be placed in the resistance value of measured medium and the effective value of polar plate voltage, R ₀and E ₀be respectively potential electrode and be placed in the resistance value of gas-free described measured medium and the effective value of polar plate voltage.

Formula (2):

wherein, current air content C is volumetric concentration.

The antijamming capability transmitting in order to improve signal, the present invention adopts electric current and voltage converting unit 4 as shown in Figure 1 by the effective value of the two-way voltage of detection, i.e. the effective value E of audible communication signal _veffective value E with polar plate voltage _i, convert standard current signal (i.e. the current signal of 4～20mA) to, then by isolating output unit 5 by the driving source standard current signal I being converted to _vwith pole plate standard current signal I _itransferring to data acquisition process unit 6 calculates.

Be specially: this electric current and voltage converting unit 4 comprises driving source change-over circuit 41 and the electrode converting circuit 42 that conversion coefficient is identical, and driving source change-over circuit 41 is by the effective value E of audible communication signal _vbe converted to driving source standard current signal I _v, electrode converting circuit 42 is by the effective value E of polar plate voltage _ibe converted to pole plate standard current signal I _i; Isolation output unit 5 comprises driving source current signal isolation module 51 and electrode current signal isolation module 52, driving source and electrode current signal isolation module transfer to data acquisition process unit 6 by driving source and pole plate standard current signal respectively, and data acquisition process unit 6 is according to the interelectrode resistance value R of formula (3) computation and measurement _i, and according to the interelectrode current air content of above formula (2) computation and measurement C.

Formula (3):

because driving source change-over circuit 41 is identical with the conversion coefficient of electrode converting circuit 42, therefore, the resistance value R between the potential electrode calculating by formula (3) and formula (1) _ibe identical, carrying out voltage/current signals conversion can not affect measured value, and the i in formula (3) has identical definition with the i in formula (1).

As shown in Figure 3, ICL8038) and amplifier U1 (the present embodiment employing model be LM7332) audio excitation of the present invention source 1 can comprise that (model that the present embodiment adopts is waveform generator U2:, waveform generator U2 generates the simple alternating current sound signal that needs frequency, by the value of adjusting resistance R5, R6 and capacitor C 2, can change the frequency F of simple alternating current sound signal, its relational expression is:

Frequency F=0.33/R × C2 (getting R5=R6=R).

Amplitude and the driving force of the simple alternating current sound signal directly generating due to waveform generator U2 are limited, can not meet request for utilization, the present embodiment carries out amplitude and power amplification by amplifier U1, improves amplitude and the driving force of bridge excitation signal, thereby improves the measuring accuracy of system.

As shown in Figure 4, in the present embodiment, driving source RMS-DC converter circuit and electrode RMS-DC converter circuit can adopt identical circuit structure, driving source change-over circuit and electrode converting circuit can adopt identical circuit structure, driving source current signal isolation module and electrode current signal isolation module also can adopt identical circuit structure, existing audio excitation source is swashed to the audible communication signal of output as the concrete enforcement structure of example explanation detecting signal unit 3, electric current and voltage converting unit 4 and isolation output unit 5.

Driving source RMS-DC converter circuit 31 comprises waveform real effective conversion chip U3 (model that the present embodiment adopts is MX536) and resistance R 8.Waveform real effective conversion chip U3 is converted to the audible communication signal of input the effective value E of audible communication signal _v.

Driving source change-over circuit 41 comprises electric current and voltage conversion chip U4 (model that the present embodiment adopts is AD694), and major function is by the effective value E of the audible communication signal of waveform real effective conversion chip U3 output _vconvert the driving source standard current signal I of 4～20mA of standard to _v.

Driving source current signal isolation module 51 comprises electric current isolation module U5 (model that the present embodiment adopts is T1100), and major function is by driving source standard current signal I _vafter isolating, export data acquisition process unit 6 to.

Air content sensor of the present invention obtains the first spout current air content ρ of the residing flow field of potential electrode (medium) environment in dilatory step according to described Check processing method ₁, and obtain the second spout current air content ρ of the residing flow field of potential electrode (medium) environment in navigation determination step ₂.

As shown in Figure 5, the workflow of described data acquisition process unit 6 is:

Step a: system initialization, performs step b afterwards;

Step b: receive steering order, perform step afterwards c;

Step c: receive driving source standard current signal I by driving source A/D ALT-CH alternate channel _v, and carry out A/D conversion, perform step afterwards d;

Steps d: receive pole plate standard current signal I by electrode A/D ALT-CH alternate channel _i, and carry out A/D conversion, perform step afterwards e;

Step e: according to

the interelectrode resistance value R of computation and measurement _i, perform step afterwards f;

Step f: judge that whether the definite mode of operation of steering order is to detect current air contents, perform step in this way g, as otherwise execution step h;

Step g: according to

calculate current air content, perform step afterwards h;

Step h: the measured value that storage, demonstration and output calculate, performs step b afterwards.

Above system initialization has been mainly used in the initial setting up such as variable, sample frequency; Receiving steering order major function is the mode of operation instruction that receives current system.There are two kinds of mode of operations described data acquisition process unit 6, and except measuring the current air content of measured medium, another kind of pattern is the resistance value R obtaining between the potential electrode that potential electrode is placed in gas-free liquid (identical with measured medium) ₀, the difference of two kinds of patterns is only that the latter only need calculate resistance value R ₀, without calculating current air content according to formula (2) again.

The foregoing is only preferably embodiment of the present invention, be not used for limiting practical range of the present invention, the equivalence of in every case doing in protection scope of the present invention changes and modifies, and all should think and fall in protection scope of the present invention.

Claims (6)

1. the measuring method of the spout flow velocity of hydraulic propeller in a navigation, it is characterized in that: dynamic pressure transducer and air content sensor are installed on the platform at hydraulic propeller place by installation of sensors pedestal, make dynamic pressure transducer and air content sensor be positioned at the dead ahead of the spout of hydraulic propeller; Speed of a ship or plane measuring instrument is fixed on described platform, in order to measure the speed of a ship or plane of described platform, described measuring method comprises for the towing post step of definite dynamic pressure factor beta bigger than normal, for determining the dilatory step of platform motion effects coefficient ξ and the spout flow velocity V for definite navigation hydraulic propeller _pnavigation determination step, wherein,

Described towing post step is: towing post is fixed on the bank, and one end of towing post rope is tethered on described towing post, and the other end is bolted on the platform at hydraulic propeller place, and described towing post rope is in series with the tautness meter for measuring towing post pulling force;

While implementing towing post, start hydraulic propeller, obtain by tautness meter the pulling force f that hydraulic propeller produces in the time spraying current on towing post rope, unit is N; Obtain the first spout current dynamic pressure P of hydraulic propeller by described dynamic pressure transducer ₁, unit is Pa;

Described dynamic pressure coefficient bigger than normal

Wherein, α is the horizontal sextant angle between towing post rope and surface level, and unit is degree; S is the area of injection orifice of hydraulic propeller, and unit is m ²;

Described dilatory step is: one end of a dilatory rope is tethered on described platform, and the other end is tethered on dilatory propulsion system;

While implementing to draw, close hydraulic propeller, start dilatory propulsion system, pull described platform motion by dilatory propulsion system, and obtain the second spout current dynamic pressure P of hydraulic propeller by described dynamic pressure transducer ₂, unit is Pa; Obtain the first spout current air content ρ of hydraulic propeller by described air content sensor ₁, unit is %; Obtain the first speed of a ship or plane V of hydraulic propeller place platform by described speed of a ship or plane measuring instrument _h1, unit is ms;

Pass through

determine platform motion effects coefficient ξ, wherein, ρ _mthe hydrostatic density of place medium during for described platform motion, unit is kgm ³;

Described navigation determination step is: start hydraulic propeller, make hydraulic propeller drive place platform motion, obtain the 3rd spout current dynamic pressure P of hydraulic propeller by described dynamic pressure transducer ₃, unit is Pa; Obtain the second spout current air content ρ of hydraulic propeller by described air content sensor ₂, unit is %; Obtain the second speed of a ship or plane V of hydraulic propeller place platform by speed of a ship or plane measuring instrument _h2, unit is m/s;

Pass through

determine spout flow velocity V _p, the unit of spout flow velocity is m/s.

2. measuring method according to claim 1, is characterized in that: described dynamic pressure transducer and air content sensor are all installed on the position of dead ahead 70mm～80mm that is positioned at spout.

3. measuring method according to claim 1, it is characterized in that: described tautness meter, dynamic pressure transducer, air content sensor and speed of a ship or plane measuring instrument and process computer communication connection, so that the signal collecting is transferred to process computer, to obtain the spout flow velocity of dynamic pressure coefficient bigger than normal, platform motion effects coefficient and hydraulic propeller by process computer.

4. according to the measuring method described in any one in claims 1 to 3, it is characterized in that: the Check processing method of described air content sensor is:

Step 1: the potential electrode of measuring bridge is placed in to measured medium, and wherein, described measuring bridge comprises that resistance value is R _sbridge resistor and described potential electrode, the audible communication signal of positive and negative constant amplitude is inputed to the two ends of the series circuit that described potential electrode and bridge resistor form, wherein, the two ends of potential electrode are as the output terminal output polar plate voltage of measuring bridge;

Step 2: the effective value E that obtains audible communication signal _veffective value E with the polar plate voltage of potential electrode _i;

Step 3: obtain the resistance value R between potential electrode _i, wherein,

the corresponding potential electrode of i=p is placed in the detection limit of described measured medium, and the corresponding potential electrode of i=0 is placed in the detection limit of gas-free described measured medium;

Step 4: the interelectrode current air content of computation and measurement ρ, wherein,

wherein, current air content ρ is volumetric concentration; R _pfor potential electrode is placed in the resistance value of measured medium, R ₀for potential electrode is placed in the resistance value of gas-free described measured medium;

Described air content sensor obtains the first spout current air content ρ of the residing flow field of potential electrode environment in dilatory step according to described Check processing method ₁, and obtain the second spout current air content ρ of the residing flow field of potential electrode environment in navigation determination step ₂.

5. measuring method according to claim 4, is characterized in that: in step 2, obtain the effective value E of described audible communication signal by driving source RMS-DC converter circuit _v, obtain the effective value E of described polar plate voltage by electrode RMS-DC converter circuit _i; In step 2, the effective value E of audible communication signal _vbe converted to driving source standard current signal I through driving source change-over circuit _v, the effective value E of polar plate voltage _ibe converted to pole plate standard current signal I through electrode converting circuit _i, wherein, driving source change-over circuit is identical with the conversion coefficient of electrode converting circuit;

Described air content sensor is by its data acquisition process unit execution step 3 and 4, and described driving source standard current signal inputs in data acquisition process unit through driving source current signal isolation module, pole plate standard current signal I _iinput to data acquisition process unit through electrode current signal isolation module; Described data acquisition unit basis

computation and measurement electrode is placed in the resistance value R of described measured medium _pand potential electrode is placed in the resistance value R of gas-free described measured medium ₀.

6. measuring method according to claim 4, is characterized in that: the amplitude of described audible communication signal is ± 12V～± 18V that frequency is 1500Hz～3000Hz.

Images