Gas mass flow measuring device for engine

Abstract

A gas mass flow measuring device for an engine belongs to the technical field of gas mass flow measurement and comprises a gas mass flow seat, a fixing bolt and a differential pressure transducer, the interior of the gas mass flow seat is of a through hole structure, and the gas mass flow seat is divided into a gas smooth transition area, a convergence area, an advection area and a diffusion area in the gas flow direction. A sensor mounting base is arranged on the outer sides of the convergence area and the advection area, an inlet pressure measuring channel and an outlet pressure measuring channel are arranged in the sensor mounting base, and a differential pressure sensor is fixed on the sensor mounting base through a fixing bolt. According to the flow testing device, gas is converged into the smooth transition area, the convergence area is processed into a circular arc to accelerate gas flow speed and reduce pressure, the advection area enables the pressure and the speed to be more stable after the gas passes through the convergence area, and the diffusion area is a gas pressure recovery process. The gas mass flow is calculated through the pressure difference of the two pressure positions, the measurement precision is high, the structure is simple, and the device is suitable for mass measurement of air, fuel gas and tail gas.

Description

Technical Field

[0001] The utility model relates to a measuring device in the technical field of mass measurement, in particular to an engine gas mass flow measuring device which is suitable for air gas measurement, fuel gas measurement and tail gas measurement. Background Art

[0002] Gas mass flowmeter is an instrument used to measure the volume flow of gas, which is often used in industrial production, environmental protection testing, experimental research and other fields. Unlike traditional volume flowmeters, gas mass flowmeters can accurately calculate the mass flow of gas by measuring the density and temperature of the gas, as well as the velocity and pressure of the fluid. Compressed air flowmeters can be measured by target flowmeters, which not only have the characteristics of traditional orifice plate, turbine, vortex street and other flowmeters without moving parts, but also have measurement accuracy comparable to volumetric flowmeters. In addition to its unique anti-interference and anti-impurity properties, it can replace the flow measurement problems that can be measured by conventional flowmeters. The flowmeter has good adaptability in working conditions where flow measurement is difficult, such as small flow, high viscosity, easy condensation and blockage, high temperature, strong corrosion, and strong vibration.

[0003] However, the existing flow meters are relatively complex in structure and installation, and are relatively expensive; although flow meters with simple structures are cheap, they have low measurement accuracy. Summary of the invention

[0004] Aiming at the deficiencies of the prior art, the utility model provides a device for measuring the mass flow rate of engine gas, which has not only a simple structure and a low price, but also a relatively high measurement and control accuracy.

[0005] The utility model is realized by the following technical scheme, the utility model comprises a gas mass flow seat, fixing bolts, and a differential pressure sensor, the interior of the gas mass flow seat is a through-hole structure, and the gas mass flow seat is divided into a gas smooth transition zone, a convergence zone, a flat flow zone, and a diffusion zone along the airflow direction, a sensor mounting base is arranged on the outer sides of the convergence zone and the flat flow zone, an inlet pressure measuring channel and an outlet pressure measuring channel are arranged inside the sensor mounting base, and the differential pressure sensor is fixed on the sensor mounting base by fixing bolts; the lower port of the inlet pressure measuring channel is connected to the internal cavity of the rear end part of the smooth transition zone, the lower port of the outlet pressure measuring channel is connected to the internal cavity of the middle part of the flat flow zone, the upper port of the inlet pressure measuring channel is connected to the intake pressure measuring channel of the differential pressure sensor, and the upper port of the outlet pressure measuring channel is connected to the outlet pressure measuring channel of the differential pressure sensor.

[0006] Furthermore, in the present invention, the cross-sections of the internal cavities of the gas smooth transition zone, the convergence zone, the advection zone, and the diffusion zone are all circular, and the inlet pressure measurement channel and the outlet pressure measurement channel are both in the shape of straight cylinders.

[0007] Furthermore, in the utility model, the internal cavity of the gas smooth transition zone is a cylindrical structure; the internal cavity of the convergence zone is composed of two levels of arc transitions, the first level arc is tangent to the plane, the first level arc and the second level arc are tangent, and the second level arc is tangent to the internal cavity of the horizontal flow zone; the internal cavity of the horizontal flow zone is a cylindrical structure; the internal cavity of the diffusion zone is a truncated cone structure, and its front end cross-sectional area is smaller than the rear end cross-sectional area.

[0008] Furthermore, in the present invention, the cross-sectional area of ​​the gas smooth transition zone inlet is the same as the cross-sectional area of ​​the diffusion zone outlet.

[0009] Furthermore, the utility model also includes a mounting flange, which is arranged at the rear end of the diffusion zone.

[0010] Compared with the prior art, the beneficial effects of the utility model are as follows: the utility model has reasonable design, simple structure, high measurement accuracy, and is suitable for measuring various engine-related gases such as air gas, fuel gas and exhaust gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a three-dimensional structural schematic diagram of an embodiment of the utility model;

[0012] Figure 2 for Figure 1 Left view of

[0013] Figure 3 A cross-sectional view of an embodiment of the utility model;

[0014] Among them, 1. gas mass flow seat, 2. fixing bolts, 3. differential pressure sensor, 101. gas smooth transition zone, 102. convergence zone, 103. advection zone, 104. diffusion zone, 105. sensor mounting base, 106. inlet pressure measurement channel, 107. outlet pressure measurement channel, 108. mounting flange. DETAILED DESCRIPTION

[0015] In order to make the contents of the present invention easier to understand, the technical scheme of the present invention is further explained below in conjunction with specific implementation methods. The examples are only used to illustrate the present invention, but the present invention is not limited to the contents. The operation methods in the following examples without specifying specific conditions are usually carried out under conventional conditions or in accordance with the product instructions. The chemical reagents without specifying the manufacturer are all conventional medicines that comply with national standards and can be purchased on the market.

[0016] Example

[0017] like Figures 1 to 3As shown, the utility model includes a gas mass flow seat 1, a fixing bolt 2, and a differential pressure sensor 3. The interior of the gas mass flow seat 1 is a through-hole structure. Along the airflow direction, the gas mass flow seat 1 is divided into a gas smooth transition zone 101, a convergence zone 102, a flat flow zone 103, and a diffusion zone 104. A sensor mounting base 105 is arranged on the outside of the convergence zone 102 and the flat flow zone 103. An inlet pressure measuring channel 106 and an outlet pressure measuring channel 107 are arranged inside the sensor mounting base 105. The differential pressure sensor 3 is fixed on the sensor mounting base 105 by the fixing bolt 2; the lower port of the inlet pressure measuring channel 106 is connected to the internal cavity of the rear end portion of the smooth transition zone 101, the lower port of the outlet pressure measuring channel 107 is connected to the internal cavity of the middle portion of the flat flow zone 103, the upper port of the inlet pressure measuring channel 106 is connected to the intake pressure measuring channel of the differential pressure sensor 3, and the upper port of the outlet pressure measuring channel 107 is connected to the outlet pressure measuring channel of the differential pressure sensor 3. The cross-sections of the internal cavities of the gas smooth transition zone 101, the convergence zone 102, the advection zone 103, and the diffusion zone 104 are all circular, and the inlet pressure measurement channel 106 and the outlet pressure measurement channel 107 are both in the shape of straight cylinders; a mounting flange 108 is arranged at the rear end of the diffusion zone 104. The internal cavity of the gas smooth transition zone 101 is a cylindrical structure; the internal cavity of the convergence zone 102 is composed of two-stage arc transitions, the first-stage arc is tangent to the plane, the first-stage arc is tangent to the second-stage arc, and the second-stage arc is tangent to the internal cavity of the advection zone 103; the internal cavity of the advection zone 103 is a cylindrical structure; the internal cavity of the diffusion zone 104 is a truncated cone structure, and its front cross-sectional area is smaller than the rear cross-sectional area. The inlet cross-sectional area of ​​the gas smooth transition zone 101 is the same as the outlet cross-sectional area of ​​the diffusion zone 104.

[0018] During the implementation of the utility model, the pressure fluctuation of the gas in the gas smooth transition zone 101 is large before it flows into this area from the unknown pipeline. The pressure fluctuation is reduced when passing through this area. A pressure tapping port is set in this area for obtaining the inlet pressure. The pressure tapping hole can be an inclined hole or a straight hole. The hole method depends on the installation of the pressure sensor. The internal cavity of the convergence zone 102 is composed of two-stage arc transitions. The first-stage arc is tangent to the plane, the first-stage arc is tangent to the second-stage arc, and the second-stage arc is tangent to the advection zone. The gas passes through the two-stage arc. The speed gradually increases and the pressure decreases accordingly. The advection zone 103 makes the pressure and speed of the gas more stable after passing through the convergence zone, and a pressure tapping port is set at the center of the advection zone. The diffusion zone 104 is the process of gas pressure recovery. The pressure gradually increases and the speed decreases after passing through the diffusion zone. After flowing through this area, the pressure returns to a stable state. The pressure sensor 3 is fixed on the gas mass flow seat 1. The pressure sensor 3 is used to measure the pressure difference before and after the gas, and the gas mass flow is calculated by measuring the pressure difference before and after.

[0019] When measuring gas quality, the gas flows into the gas smooth transition area 101. A pressure tapping hole is set near the convergence area 102 in the gas smooth transition area 101 to obtain the inlet pressure. The convergence area 102 is processed into an arc to accelerate the gas flow rate and reduce the pressure. Advection 103 makes the pressure speed of the gas more stable after passing through the convergence area. Diffusion 104 is the process of gas pressure recovery. The four areas constitute a gas mass flow measurement seat 1. The measurement seat is equipped with a differential pressure sensor 3. This differential pressure sensor 3 can obtain the pressure difference formed at two pressure positions to calculate the gas mass flow rate.

[0020] The above embodiments are merely illustrative of the design principle and use of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by a person with ordinary knowledge in the relevant technical field without departing from the spirit and technical ideas disclosed in the present invention shall still be covered by the claims of the present invention.

Claims

1. A gas mass flow measurement device for an engine, comprising a gas mass flow seat (1), a fixing bolt (2), and a differential pressure sensor (3), characterized in that: The gas mass flow seat (1) has a through-hole structure inside. Along the gas flow direction, the gas mass flow seat (1) is divided into a gas smooth transition zone (101), a convergence zone (102), a flat flow zone (103), and a diffusion zone (104). A sensor mounting base (105) is arranged outside the convergence zone (102) and the flat flow zone (103). An inlet pressure measurement channel (106) and an outlet pressure measurement channel (107) are arranged inside the sensor mounting base (105). The differential pressure sensor (3) is fixed to the sensor mounting base (105) by means of fixing bolts (2). The lower port of the inlet pressure measurement channel (106) is connected to the internal cavity at the rear end of the smooth transition zone (101), the lower port of the outlet pressure measurement channel (107) is connected to the internal cavity at the middle part of the advection zone (103), the upper port of the inlet pressure measurement channel (106) is connected to the intake pressure measurement channel of the differential pressure sensor (3), and the upper port of the outlet pressure measurement channel (107) is connected to the outlet pressure measurement channel of the differential pressure sensor (3).

2. The engine gas mass flow measurement device according to claim 1, characterized in that The cross-sections of the internal cavities of the gas smooth transition zone (101), the convergence zone (102), the advection zone (103), and the diffusion zone (104) are all circular, and the inlet pressure measurement channel (106) and the outlet pressure measurement channel (107) are both in the shape of straight cylinders.

3. The engine gas mass flow measurement device according to claim 2, characterized in that The internal cavity of the gas smooth transition zone (101) is a cylindrical structure; the internal cavity of the convergence zone (102) is composed of two-level arc transitions, the first-level arc is tangent to the plane, the first-level arc and the second-level arc are tangent, and the second-level arc is tangent to the internal cavity of the advection zone (103); the internal cavity of the advection zone (103) is a cylindrical structure; the internal cavity of the diffusion zone (104) is a truncated cone structure, and its front end cross-sectional area is smaller than the rear end cross-sectional area.

4. The engine gas mass flow measurement device according to claim 3, characterized in that The inlet cross-sectional area of ​​the gas smooth transition zone (101) is the same as the outlet cross-sectional area of ​​the diffusion zone (104).

5. The engine gas mass flow measurement device according to claim 2, characterized in that The invention also comprises a mounting flange (108), which is arranged at the rear end of the diffusion zone (104).

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