35 results about "Sonic nozzle" patented technology

The invention relates to valve electric control, in particular to a high-frequency-response wide-range dynamic flow generation device control method, which comprises a stable flow setting step, a parameter acquisition step, a dynamic flow constant flow scheme determination step, a stability calculation step and a valve adjustment step. According to the dynamic flow generation device composed of the multiple branch sonic nozzles with different throat diameters, the dynamic flow generation device can select different sonic nozzles according to the required flow value to be detected to achieve the flow value to be detected, and the flow precision of the dynamic flow generation device is improved. Asynchronous switching is carried out on the high-speed switching valves, the starting sequence and the interval time of the high-speed switching valves are set according to the time that the high-speed switching valves can achieve stable output flow, and therefore flow fluctuation generated when the valve state of the high-speed switching valves changes is eliminated, and the stability of the high-speed switching valves is improved. And the response speed and the flow generation precision of the dynamic flow generation device are improved.

The invention relates to a process gas flow in-situ calibration device based on a sonic nozzle array, and relates to the technical field of semiconductor gas flow calibration, the process gas flow in-situ calibration device comprises a sonic nozzle array, the sonic nozzle array is connected in series with the downstream of a to-be-calibrated gas flow sensor or a mass flow controller, and is used for covering a wide-range-ratio flow range; the fixed containing cavity is connected with the sonic nozzle array in series and used for receiving and temporarily storing the gas medium passing through the fixed containing cavity and the sonic nozzles; and the sensing and control module is used for calculating the actual mass flow rate by collecting the pressure and temperature of a gas medium used for semiconductor processing in real time, and comparing the actual mass flow rate with a measured value of the instrument to be calibrated to complete in-situ calibration. The device has the advantages that disassembly is not needed during wide-range in-situ calibration of the semiconductor process gas flow, and the ultra-clean environment characteristic of the device is kept.

The invention provides a method for correcting the outflow coefficient of a sonic nozzle and a method for correcting the flow of gas flowing out of the sonic nozzle, and belongs to the technical field of metrology. The method for correcting the outflow coefficient of the sonic nozzle comprises the steps that according to Reynolds number traceability calculation values under different stagnation conditions, a theoretical calculation value during outflow coefficient traceability is obtained; according to the outflow coefficient traceability value, the Reynolds number traceability calculation value and the outflow coefficient traceability theoretical calculation value under different stagnation conditions, obtaining a correction relationship among the Reynolds number traceability calculation value, the outflow coefficient traceability value and the outflow coefficient traceability theoretical calculation value under any stagnation condition during traceability; and according to the Reynolds number calculation value, the outflow coefficient theoretical calculation value and the correction relation under any stagnation condition during actual measurement, an outflow coefficient correction value under any stagnation condition during actual measurement is obtained. The method for correcting the outflow coefficient of the sonic nozzle is not limited by the Reynolds number, and the outflow coefficient of the small-throat-diameter sonic nozzle under different stagnation conditions can be accurately calculated.

The loop type natural gas secondary calibration system comprises a loop unit, a flow and pressure control unit, a temperature control unit, a leak detection unit and a control unit, and natural gas circulates in the loop unit; the flow and pressure control unit, the temperature control unit and the leak detection unit are electrically connected with the control unit; the flow and pressure control unit is used for stabilizing the flow and pressure of the natural gas in the loop unit; the temperature control unit is used for stabilizing the temperature of natural gas in the loop unit; the leak detection unit is used for detecting whether two ends of the detected flowmeter leak or not; the loop unit is further provided with a first electric ball valve, a differential pressure transmitter, a second temperature transmitter and a sonic nozzle standard meter. The calibration method comprises the steps of calibration operation preparation, calibration operation and leak detection operation. The system can simplify the natural gas verification and adjustment process, reduces the dependence on a natural gas transmission station, has the leakage detection capability, and is worthy of popularization and application.

The invention relates to the field of valve electric control, in particular to a dynamic flow generation device control method based on a rapid switching array, which uses a high-speed switching three-way valve to replace a traditional two-way valve, so that a flow generation branch can rapidly correspond to a flow switching control instruction, the time for adjusting the flow of the device to a stable state is shortened, and the flow switching efficiency is improved. Flow fluctuation is reduced, and the overall stability of the system is improved; the dynamic flow generation device is composed of the dynamic flow generation branches controlled by multiple valves, and the flow of the flow generation branches is controlled through the throat area of the sonic nozzle, so that the dynamic flow detected by the flow meter can reflect the actual flow characteristic more accurately, and the detection authenticity of the flow meter to be detected is improved; after the reliability of the multiple flow generation branches is ranked, the flow generation branch combination with the highest reliability is selected to reach the set flow, namely the to-be-detected flow value, so that the flow control and test precision and accuracy can be improved.

The invention discloses a measuring device and method for calibrating gas mass flow, and belongs to the technical field of flow measurement. The device comprises a gas inlet pipe provided with a pressure regulating valve; the stagnation container is communicated with the air inlet pipe; the plurality of sonic nozzles are respectively arranged on the stagnation container, and each sonic nozzle is provided with an upstream end communicated with the stagnation container and a downstream end communicated with the collection container; a collection container; the exhaust pipe is communicated with the collecting container; the pressure measuring piece I, the temperature measuring piece I and the humidity measuring piece are connected to the stagnation container; and the second pressure measuring piece is connected to the collection container. The calibration method comprises the following steps: opening the pressure regulating valve and regulating until each sonic nozzle is in a critical flow state; and after the measured data is stable, collecting and calculating the standard flow. According to the gas mass flow metering device, the field gas source can be directly utilized, measurement can be conveniently and rapidly carried out, the field calibration problem of the gas mass flow metering device can be solved, it is guaranteed that the flow value of the gas mass flow metering device is accurate, and meanwhile the gas mass flow metering device can be used under the laboratory condition.

The present invention discloses a rotary sonic nozzle for a coaxial cylindrical deflagration drive device, comprising an air inlet cap, an air outlet cap, and an orifice plate; the air inlet cap is provided with an air inlet channel having a first air inlet section and a first air outlet section; the air outlet cap is provided with an air outlet channel having a second air inlet section and a second air outlet section; the orifice plate is located between the air inlet cap and the air outlet cap; the orifice plate is provided with small holes, each of which has a different diameter; the diameter of the small holes on the orifice plate gradually decreases along the circumferential direction; the air inlet cap is provided with a contact protrusion; the air outlet cap is provided with a contact groove; the contact protrusion has multiple first protruding surfaces, the edge of the orifice plate is provided with a second protruding surface, and the contact groove is provided with a concave surface that matches the first and second protruding surfaces. The present invention can limit the airflow velocity when charging the combustible mixed gas into the deflagration drive section, so that it meets the stringent requirements of the deflagration drive for the mixing uniformity of the combustible gas.

The invention relates to an aero-engine ground test bed air inlet flow pipe calibration system, and relates to the technical field of air inlet flow pipe calibration, an air extractor is used for supplying set mass flow, a standard air inlet flow pipe is used for measuring and calculating actual mass flow, and then a local actual flow coefficient is obtained through back calculation. A calibration coefficient can be obtained through calculation according to the coefficient and used for calibrating the sonic nozzle, calculating theoretical measurement values of other flowmeters, and comparing the theoretical measurement values with actual values for verification; after the sonic nozzle is calibrated, the standard gas inlet flow pipe can be replaced by the gas inlet flow pipe to be calibrated to be used as a sonic nozzle method gas flow calibration device, and then other gas inlet flow pipes are calibrated. Compared with a traditional mode of using a regulating valve to regulate the flow to measure the flow of the engine, the flow metering error can be corrected to a certain degree, data are more accurate, and the method is reliable, simple, convenient, high in efficiency and safer.

The invention relates to an automatic analysis system and method for test data of sonic nozzle products, and belongs to the technical field of data processing. The method comprises the following steps: importing a test data file and displaying an original data curve; in the multi-mode data analysis mode, working conditions needing to be calculated and analyzed are selected; automatically calling stored historical parameter configuration; calculating parameters are manually adjusted; carrying out data processing and analysis by adopting an inflection point judgment algorithm based on dynamic threshold adjustment, inputting the obtained data into a correlation analysis model, and calculating to obtain a test data curve of each channel and a data correlation analysis result; the test data analysis curve and the data analysis result are visually displayed; and automatically generating a test report according to a preset template. According to the method, human errors in the data processing process can be eliminated, the visualization effect of the data is enhanced, the labor cost is reduced, and the working efficiency is improved.

The invention relates to the technical field of gas flow measurement, and discloses a deposition early warning method and system for a sonic nozzle gas flow standard device, and the method comprises the steps: collecting a dynamic pressure signal of upstream gas of a sonic nozzle, and recognizing and segmenting a transient risk window; transmitting an ultrasonic detection signal to the airflow in the sonic nozzle, receiving a penetration signal of the airflow, and extracting a coherent acoustic characteristic quantity used for representing the state of a boundary layer of the throat wall surface of the nozzle; and performing comparative analysis on the coherent acoustic characteristic quantity and a pre-established reference characteristic spectrum to generate early warning information. According to the method, a progressive accurate diagnosis chain from macroscopic fluid dynamic capture to microscopic surface effect detection to metering risk quantitative evaluation is constructed, so that the fundamental technical difficulty that silence misalignment caused by deposition of a sonic nozzle gas flow standard device is difficult to perceive and quantitatively evaluate is solved; and the reliability of the detection result of the device is improved.

The utility model discloses a loop type natural gas calibration system with leak detection capability, which relates to the technical field of natural gas metering and comprises a loop unit, a flow and pressure control unit, a temperature control unit, a leak detection unit and a control unit, and natural gas circulates in the loop unit. The flow and pressure control unit, the temperature control unit and the leak detection unit are electrically connected with the control unit; the flow and pressure control unit is used for stabilizing the flow and pressure of the natural gas in the loop unit; the temperature control unit is used for stabilizing the temperature of natural gas in the loop unit; the leak detection unit is used for detecting whether two ends of the detected flowmeter leak or not; a first electric ball valve, a differential pressure transmitter, a second temperature transmitter and a sonic nozzle standard meter are further arranged on the loop unit. The system can simplify the natural gas verification and adjustment process, reduces the dependence on a natural gas transmission station, has the leakage detection capability, and is worthy of popularization and application.

This invention discloses a loop-type natural gas secondary calibration system and calibration method, including a loop unit, a flow and pressure control unit, a temperature control unit, a leak detection unit, and a control unit. Natural gas circulates within the loop unit. The flow and pressure control unit, temperature control unit, and leak detection unit are all electrically connected to the control unit. The flow and pressure control unit stabilizes the flow rate and pressure of the natural gas within the loop unit; the temperature control unit stabilizes the temperature of the natural gas within the loop unit; the leak detection unit detects whether leaks have occurred at both ends of the flow meter under test. The loop unit also includes a first electric ball valve, a differential pressure transmitter, a second temperature transmitter, and a sonic nozzle standard gauge. The calibration method includes calibration preparation, calibration operation, and leak detection operation. This system simplifies the natural gas verification and regulation process, reduces dependence on natural gas transmission stations, and has leak detection capabilities, making it worthy of widespread application.

The application discloses a rectifying nozzle type flow divider and a design method thereof, which makes refrigerant flow symmetrically and uniformly in the flow divider and provides a theoretical model for the design of the flow divider. The flow divider comprises a cyclone section, a rectifying section and a distribution section connected in sequence; the cyclone section comprises a cyclone pipe and cyclone blades arranged in the cyclone pipe; the cyclone blades are composed of a center column and a spiral plate mounted on the center column. The distribution section comprises a distribution cavity and a plurality of branch pipes; the inlet of each branch pipe is located in the distribution cavity; each branch pipe is provided with a flow dividing sonic nozzle; the plurality of branch pipes and the flow dividing sonic nozzles are distributed along the circumference of the distribution cavity; and the center lines of the branch pipes and the flow dividing sonic nozzles are parallel to the center line of the distribution cavity. The flow divider can make the refrigerant flow symmetrically and uniformly in the flow divider, improve the heat exchange performance of the evaporator and improve the refrigerating capacity of the evaporator.

The present invention relates to the technical field of flow measurement, and particularly relates to an air flow detection method, which includes using a sonic nozzle to measure the ultimate pressure of a stagnation chamber; calculating the ultimate pressure by using a Newton cooling model algorithm to obtain a target pressure value; making a rationality judgment on the target pressure value. If it is reasonable, the target nozzle is obtained and the next step is executed. If it is unreasonable, the sonic nozzle is replaced according to the rule of nozzle size and then the first step is executed; using the target nozzle to perform recursive search in a basic table to obtain an equivalent aperture, a flow value, and a nozzle number; searching for adjacent combined nozzles of the nozzle number, and performing flow combination on the adjacent combined nozzles based on the equivalent aperture and the flow value to obtain a combined nozzle; measuring the flow of the combined nozzle by using a Newton cooling model algorithm to obtain target data; fitting the target data according to the fluid Bernoulli equation to obtain a target result, solving the problem of the long detection time of the existing detection method.

The invention relates to the technical field of gas flow detection, in particular to positive pressure sonic nozzle air flow detection equipment which comprises an air compressor, a conveying connecting pipe, a filter, an automatic alignment adding device, a flow meter, an extrusion alignment device, a first sealing butt-joint pipe, a second sealing butt-joint pipe, a sonic nozzle, a supporting frame and a buffer container. The conveying connecting pipe is fixedly connected to the air compressor, the filter is arranged on the outer side of the air compressor, the conveying connecting pipe is fixedly connected with the two ends of the filter, and the buffering container is fixedly arranged on the side, away from the air compressor, of the filter through the conveying connecting pipe. The supporting frame is fixedly connected to a conveying connecting pipe arranged on the side, away from the filter, of the buffering container. By collecting temperature and pressure data in real time and automatically correcting gas density and compression factors, the influence of environmental factors on a measurement result is reduced, the buffer container is combined with the proportioning valve, the pressure fluctuation can be controlled within + / -0.2%, and continuous and stable gas flow is ensured.

The invention discloses a rectifying nozzle type flow divider and a design method thereof, so that a refrigerant flows symmetrically in the flow divider and is uniformly divided, and a theoretical model is provided for the design of the flow divider. The flow divider comprises a rotational flow section, a rectification section and a distribution section which are connected in sequence; the rotational flow section comprises a rotational flow pipe and rotational flow blades arranged in the rotational flow pipe, and each rotational flow blade is composed of a center column and a spiral plate installed on the center column. The distribution section comprises a distribution cavity and a plurality of branch pipes, an inlet of each branch pipe is located in the distribution cavity, a flow dividing sonic nozzle is arranged in the inlet of each branch pipe, and the branch pipes and the flow dividing sonic nozzles on the branch pipes are evenly distributed along the circumference with the center of the distribution cavity as the circle center. The center line of each branch pipe and the center line of the diversion sonic nozzle on the branch pipe are parallel to the center line of the distribution cavity. According to the flow divider, refrigerants can flow symmetrically in the flow divider, flow dividing is uniform, the heat exchange performance of an evaporator is improved, and the refrigerating capacity of the evaporator is improved.

The invention discloses a gas flow measurement error correction method and system based on a critical flow sonic nozzle, and relates to the technical field of gas flow measurement, and the method comprises the following steps: carrying out logarithmic operation on a sharpened average power spectrum, executing inverse discrete Fourier transform to obtain a real cepstrum sequence, and extracting the characteristics of a low cepstrum interval to obtain the gas flow measurement error. Calculating a characteristic factor representing the state of the boundary layer of the nozzle throat; meanwhile, the Reynolds number under the current flowing working condition is calculated on the basis of static pressure and static temperature data, the ISO standard outflow coefficient is dynamically corrected in combination with a pre-calibrated Reynolds number partition sensitivity coefficient, and the corrected outflow coefficient is obtained. By performing autocorrelation analysis on a real cepstrum high delay interval, judgment on a critical flow state of a nozzle is realized, and actual mass flow is calculated based on a corrected outflow coefficient under a stable critical flow condition, so that the accuracy and stability of flow measurement under a wide working condition are improved, and a system error introduced by a traditional static correction model is reduced.

The present invention provides a particle manufacturing device and a manufacturing method for frozen particles capable of quickly manufacturing frozen particles while preventing clogging of a nozzle due to freezing. The present invention provides a particle manufacturing device including: a freezing chamber in which frozen particles obtained by freezing an object to be treated containing moisture in a particulate form are accommodated; an ultrasonic nozzle configured to discharge the object to be treated after or before being frozen in a particulate form into the freezing chamber; and a decompression device configured to decompress the freezing chamber, in which the moisture is evaporated due to decompression, and the frozen particles are cooled and frozen by the evaporation of the moisture.

The present invention discloses a medium comprehensive management system for coaxial cylindrical deflagration driving technology, which includes a driving gas supply system, a driven gas supply system, a vacuum pumping system, a drying system, and an exhaust gas emission system; the vacuum pumping system includes a driving section vacuum valve, a rear vacuum valve of the driving gas supply line, a front vacuum valve of the driving gas supply line, a driven section vacuum valve, a front vacuum valve of the driven gas supply line, a main valve of a low vacuum pump, a low vacuum pump, a main valve of a high vacuum pump, and a high vacuum pump; along the air extraction direction of the driving gas, the driving section vacuum valve, the main valve of the low vacuum pump, and the low vacuum pump are sequentially connected through a first vacuum pumping pipeline, and the tail end of the first vacuum pumping pipeline is communicated with the deflagration driving section, and a second vacuum pumping pipeline is communicated with a first gas supply pipeline connected between a driving gas pressure reducer and a driving gas sonic nozzle. The low vacuum pump and the high vacuum pump cooperate with each other to pump out the gas in the pipeline before the experiment and remove the remaining water vapor after the experiment.

The utility model discloses a positive pressure method sound speed nozzle air flow test platform's calibrating device, including the support guide frame for supporting, is located the rear end surface center of support guide frame fixedly seted up servo motor, and is located servo motor's output setting has two -way screw rod. The utility model discloses a guide device is set up, when the air flow of different models flowmeter is carried out air flow verification, and the speed reducer can through the sliding limit of transmission axle and transmission guide groove, and then synchronous belt drive two sets of positioning gear rotate, make positioning gear can synchronous belt drive two sets of transmission gear ring and carry out the overturning of cycle 90 degrees to the subsequent first detection pipe and second detection pipe of different diameter carry out alignment, effectively improve the adaptability of equipment to the different models flowmeter and carry out the verification, and then improve the practicality of equipment.

The utility model relates to the technical field of gas meter detection, and discloses a sonic nozzle fluid detection device which comprises a stagnation container. The nozzle assembly comprises a nozzle mounting plate and a sonic nozzle body; the backpressure container is provided with a second cavity, and the stagnation container is detachably connected with the backpressure container through a nozzle mounting plate; the base is provided with a bearing surface, a guide rail is arranged on the bearing surface, the guide rail extends in the arrangement direction of the stagnation container and the backpressure container, and the stagnation container is in sliding connection with the guide rail through a first connecting mechanism. When the connection relation among the stagnation container, the nozzle mounting plate and the backpressure container is removed, the stagnation container can be easily pushed towards one side far away from the backpressure container along the extension direction of the guide rail, so that the disassembly of the sonic nozzle body is conveniently realized. Therefore, when large-flow detection is carried out, inconvenience caused by the size and the quality of the device can be overcome, and the disassembly and assembly efficiency of the sonic nozzle body is improved.

The present invention discloses a device for simulating high-temperature combustion gas after the decomposition of an aqueous hydrogen peroxide solution, which comprises a three-component injector, a combustion chamber, and a sonic nozzle arranged coaxially in sequence; the three-component injector includes a hydrogen nozzle, an oxygen nozzle, and a water nozzle; the water nozzle is coaxially installed at the injection end of the combustion chamber, and the water nozzle includes a central through hole, water spray holes, a water collecting cavity, and a water inlet; the water spray holes are arranged circumferentially along the central through hole; one end of the hydrogen nozzle is coaxially inserted into the central through hole of the water spray hole; the other end is coaxially provided with a hydrogen gas collecting cavity; a hydrogen gas spray hole communicated with the hydrogen gas collecting cavity is coaxially arranged in the center of the hydrogen nozzle; the oxygen nozzle includes an oxygen gas collecting cavity and an oxygen gas spray hole; an oxygen gas spray hole is formed between the outer wall surface of the hydrogen nozzle and the inner wall surface of the central through hole. The present invention can realize the catalytic decomposition of hydrogen peroxide simulated by using three components of hydrogen, oxygen, and water, and the flow rates of the three components are adjustable within a certain range, so as to meet the catalytic decomposition of hydrogen peroxide with different concentrations and temperatures.

The present application relates to turbine blowing test device and method, specifically relates to turbine blowing test pressure ratio continuous adjusting device and method, its purpose is to solve the existing turbine blowing test method cannot continuously adjust pressure ratio, test efficiency is low, test precision is poor, and the problems such as expensive price, adjusting precision is poor, resolution is low of using large-diameter regulating valve;The present application is simultaneously provided with back pressure orifice plate and bypass pipe equipped with regulating valve on turbine outlet pipe, uses regulating valve to adjust turbine pressure ratio, so that the device can continuously test after once calibration;The present application can also be equipped with bypass pipe with high-pressure gas source, pressure reducing valve, pre-pressure temperature measuring instrument of sonic nozzle, sonic nozzle and stop valve on turbine outlet pipe, the turbine pressure ratio is adjusted by adjusting pressure reducing valve, and continuous test can also be realized after once calibration of the device.

This invention discloses a method and system for correcting gas flow measurement errors based on a critical flow sonic nozzle, relating to the field of gas flow metering technology. The method includes performing logarithmic operations on the sharpened average power spectrum and executing an inverse discrete Fourier transform to obtain a real cepstrum sequence. By extracting features from the low cepstrum frequency range, characteristic factors representing the nozzle throat boundary layer state are calculated. Simultaneously, the Reynolds number under the current flow condition is calculated based on static pressure and static temperature data, and the ISO standard outflow coefficient is dynamically corrected using a pre-calibrated Reynolds number partition sensitivity coefficient to obtain the corrected outflow coefficient. By performing autocorrelation analysis on the high time delay range of the real cepstrum, the critical flow state of the nozzle is determined. Under stable critical flow conditions, the actual mass flow rate is calculated based on the corrected outflow coefficient, improving the accuracy and stability of flow measurement under wide operating conditions and reducing the systematic errors introduced by traditional static correction models.

The present invention discloses an integrated regulating device and method for a liquid hydrogen storage and supply system, relating to the field of hydrogen energy technology. The present invention uses a simple-structured, easily processed sonic nozzle assembly to replace existing large-volume components such as regulating valves and flow meters, and is unaffected by factors such as downstream power units and pipelines, thereby achieving coupled unification of hydrogen medium flow regulation and parameter measurement. The heat absorption characteristic of para-orthohydrogen conversion minimizes the downstream pressure of the sonic nozzle, ensuring that the corresponding sonic nozzle reaches a critical state and the calculation accuracy of the actual flow parameters is guaranteed. The characteristics of throttling heating when the hydrogen temperature is greater than the switch-back temperature and throttling cooling when it is less than the switch-back temperature are utilized to design a variety of coolant circulation methods, thereby improving the overall energy utilization efficiency of the system.

This application relates to the technical field of wind tunnel flexible nozzle profile control devices, specifically, to a method for maintaining the sonic profile of a continuous transonic wind tunnel hydraulically controlled flexible nozzle. The method includes the following steps: calculating the total load on each support node of the flexible nozzle's sonic profile; assembling the node support mechanism onto the flexible plate of the flexible nozzle; the node support mechanism includes a mechanical locking device; returning each node to its mechanical zero position; and locking the mechanical locking device; giving the hydraulic servo control system a sonic nozzle forming command; unlocking the mechanical locking device; and allowing the flexible nozzle profile to move from its mechanical zero position to the sonic nozzle profile through coordinated control by the hydraulic servo system; when the dynamic adjustment of the sonic nozzle profile meets the control accuracy requirements, locking the mechanical locking device; the hydraulic servo system exits the dynamic adjustment state; and the mechanical locking device provides the locking force to maintain the sonic nozzle profile. This achieves the goal of maintaining a more stable sonic profile of the flexible nozzle.

The utility model provides a critical flow venturi nozzle assembly and a flow detection system, and the critical flow venturi nozzle assembly comprises a critical flow venturi nozzle distributor, a pneumatic flow amplifier and a heater. The critical flow venturi nozzle distributor comprises a stagnation container, a collection container, a sonic nozzle, an air cylinder, a temperature detection device and a pressure detection device, an air inlet of the stagnation container is connected with an outlet of the pneumatic flow amplifier, the two ends of the sonic nozzle are located in the stagnation container and the collection container respectively, and the air cylinder is in driving connection with the sonic nozzle; the temperature detection device and the pressure detection device are communicated with the stagnation container and are used for detecting the gas temperature and the gas pressure in the stagnation container so as to calculate the flow of the gas to be detected; an inlet of the heater communicates with the air source assembly, and an outlet of the heater communicates with an inlet of the pneumatic flow amplifier. According to the critical flow venturi nozzle assembly and the flow detection system, the requirement for the detection environment can be lowered, and the reliability of the detection result is improved.

The invention discloses a decoupling evaluation method for leak rate and tube volume effect in gas small flow verification, which relates to the field of gas flow standard, and comprises the following steps: carrying out air tightness test on a positive pressure sonic nozzle gas flow standard device to be tested to confirm that the positive pressure sonic nozzle gas flow standard device meets a preset air tightness requirement; a leak rate measurement model is constructed, leak rate measurement is carried out under the selected multiple pressure points and flow points, and leak rates under different verification working conditions are obtained; a pipe volume effect measurement model is constructed, and the total mass change rate under different verification working conditions is obtained; deducting the leakage rate contribution under the corresponding working condition from the total mass change rate, and decoupling to obtain a tolerance rate caused by a pipe capacity effect; and the influence rule of the leakage rate and the tube volume effect on the gas small flow verification result is evaluated, and a verification optimization strategy is determined. According to the method, decoupling and independent quantification of the coupling influence of the leak rate and the tube volume effect in gas small-flow verification are achieved, and a quantitative basis is provided for evaluating device performance and optimizing verification operation.

This application relates to the field of gas flow metering technology and discloses a deposition early warning method and system for a sonic nozzle gas flow standard device. The method includes: acquiring the dynamic pressure signal of the gas upstream of the sonic nozzle, identifying and segmenting the transient risk window; emitting an ultrasonic detection signal into the gas flow inside the sonic nozzle and receiving its penetration signal, extracting coherent acoustic features to characterize the boundary layer state of the nozzle throat wall; comparing and analyzing the coherent acoustic features with a pre-established benchmark feature spectrum to generate early warning information. This application solves the fundamental technical dilemma of the silent inaccuracy caused by deposition in sonic nozzle gas flow standard devices being difficult to detect and quantify by constructing a progressive and precise diagnostic chain from macroscopic fluid dynamic capture to microscopic surface effect detection, and then to quantitative assessment of metering risks, thereby improving the reliability of the device's detection results.

The utility model discloses a vehicle-mounted sonic nozzle method gas flow standard device, which comprises a compartment body, a gas flow standard device, a gas flow standard device, a gas flow standard device and a gas flow standard device, wherein an installation chamber and a detection chamber are defined by the compartment body; the detected meter mounting module is arranged in the detection chamber; the standard verification module is arranged in the detection chamber, and the standard verification module is connected with the tested meter installation module; the power module is arranged in the mounting chamber, and the power module is constructed to exert a negative pressure suction effect on the standard verification module; and the control module is in signal connection with the power module and the standard verification module, and the control module is configured to adjust the detection range of the standard verification module and the suction pressure intensity of the power module. According to the vehicle-mounted sonic nozzle method gas flow standard device, all parts of the gas flow standard device are modularized, and maintenance and overhaul of the parts of the gas flow standard device are facilitated.