A droplet evaporation test bench with known flow field parameters

Abstract

The application provides a liquid drop evaporation test bench with known flow field parameters, which comprises an observation column, an air inlet filter pipe, a transverse flow straightener, a ring flow straightener, a vortex chamber, an air outlet valve, an air outlet filter screen, a static drop pipe, an injection capillary tube and an automatic injector; one end of the observation column is fixedly connected with the vortex chamber through the air inlet filter pipe, the transverse flow straightener and the ring flow straightener; the air outlet valve is installed in the air outlet hole of the vortex chamber; the other end of the observation column is fixedly connected with the air outlet filter screen; the static drop pipe is installed in the static hole of the air outlet filter screen; one end of the injection capillary tube is connected with the injection hole of the automatic injector, and the other end is connected with the drop pipe hole of the static drop pipe; a plurality of sensor sealing columns are installed in the sealing through grooves on the observation column; and sensors are installed in the sensor holes of the sensor sealing columns. The application solves the problems of errors and unknowns in research results caused by uncontrollable and unmeasurable weak air flow disturbance determined by the disappearance of liquid surface tension and the increase of gas-liquid interface thickness under the transcritical / supercritical condition.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of engine test, in particular to a liquid droplet evaporation test bench with known flow field parameters. BACKGROUND

[0002] In order to realize more efficient and low-pollution engines, technical measures such as high injection pressure, high supercharging and high back pressure are widely used, so that the in-cylinder temperature and back pressure are close to and exceed the critical point of fuel, which is not a small probability phenomenon, thus making the trans-critical / supercritical spray mixing an unavoidable issue for engines. Under the critical condition, the liquid phase density decreases significantly, and the gas-liquid interface is difficult to identify, and instead, a gas-liquid two-phase mixing layer mainly controlled by diffusion process appears, which is due to the disappearance of liquid surface tension and the increase of gas-liquid interface thickness. Therefore, the disintegration of liquid jet and the formation of mixed gas are no longer controlled by surface tension and aerodynamic instability, but by turbulent diffusion process. At this time, weak disturbance on the gas-liquid interface can have a great influence on the diffusion process of fuel.

[0003] For a long time, the research on trans-critical / supercritical spray has mainly focused on three aspects. One is the evaporation characteristics of single liquid droplet under trans-critical / supercritical conditions; the second is the calculation method of real fluid state equation, thermophysical properties and transport coefficients under trans-critical / supercritical conditions; the third is the stability and evolution process of trans-critical / supercritical jet mixing layer. The existing test methods, such as the main work in the constant volume combustion bomb, are to study the jet situation of the spray, which can provide test data for the above-mentioned second point. However, because the constant volume combustion bomb can only ensure that the flow field environment is approximately static relative to the dynamic process of the spray, but the weak air flow disturbance caused by temperature transfer is difficult to control and measure, and this will cause a large error in the data results due to the characteristics of trans-critical / supercritical spray.

[0004] The weak air flow disturbance is difficult to observe and control, but if a clearly observable air flow environment is artificially provided, the flow field parameters of the air flow can be observed, and the accidental air flow disturbance can be predicted and controlled. In this way, the error and unknown situation in the research results caused by the uncontrolled and unmeasurable weak air flow disturbance determined by the disappearance of liquid surface tension and the increase of gas-liquid interface thickness under trans-critical / supercritical conditions can be reduced, and the evaporation characteristics of single liquid droplet under trans-critical / supercritical conditions can be studied in an environment where the flow field parameters are known. At the same time, because the static droplet tube and the observation column in the present device provide static and dynamic flow field environments respectively, the comparison of the motion state of fuel droplets in the two can study the stability and evolution process of trans-critical / supercritical jet mixing layer. SUMMARY

[0005] Therefore, the present application aims to provide a liquid droplet evaporation test bench with known flow field parameters to solve the problems of errors and unknowns in research results caused by uncontrollable and unmeasurable weak air flow disturbance determined by the disappearance of liquid surface tension and the increase of gas-liquid interface thickness under transcritical / supercritical conditions, and provide the possibility for studying the evaporation characteristics of single liquid droplet and the stability and evolution process of transcritical / supercritical jet mixing layer under transcritical / supercritical conditions.

[0006] To achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0007] A liquid droplet evaporation test bench with known flow field parameters, comprising an observation column, an air inlet filter pipe, a transverse flow straightener, a ring flow straightener, a vortex chamber, an air exhaust valve, an air exhaust filter screen, a static dropper, an injection capillary tube and an automatic injector.

[0008] One end of the observation column is fastened to the vortex chamber through the air inlet filter pipe, the transverse flow straightener and the ring flow straightener; the air exhaust valve is installed in the air exhaust hole of the vortex chamber.

[0009] The other end of the observation column is fastened to the air exhaust filter screen, the static dropper is installed in the static hole of the air exhaust filter screen, one end of the injection capillary tube is connected to the injection hole of the automatic injector, one end is connected to the dropper hole of the static dropper, a plurality of sensor sealing columns are installed in the sealing through slot on the observation column, and the sensors are installed in the sensor holes of the sensor sealing columns.

[0010] Further, the vortex chamber is in the shape of a hollow cylinder, and the top circular surface is open; a cylindrical body is arranged at the bottom of the vortex chamber, which is an air exhaust column, and a through hole is arranged at the center of the air exhaust column, which is an air exhaust hole; a square-section air inlet column is arranged along the tangential direction of the cylinder, and the air inlet column has a square-section air inlet hole, and the inner wall of the air inlet hole is also tangent to the inner wall of the cylindrical surface of the vortex chamber.

[0011] Further, the ring flow straightener is a hemispherical sheet, and a ring-shaped flat plate is arranged at the bottom; the central axis of the ring flow straightener is coaxially arranged with the central axis of the vortex chamber, the hemispherical sheet of the ring flow straightener protrudes upward, and the ring-shaped flat plate of the ring flow straightener is tightly attached to the top flat surface of the vortex chamber.

[0012] The transverse flow straightener is a hemispherical sheet, and a ring-shaped flat plate is arranged at the bottom; the grid is arranged in transverse distribution parallel to each other; the central axis of the transverse flow straightener is coaxially arranged with the central axis of the vortex chamber, the hemispherical sheet protrudes upward, and the ring-shaped flat plate of the transverse flow straightener is tightly attached to the ring-shaped flat plate of the ring flow straightener.

[0013] The air inlet filter pipe is a hollow cylinder, the bottom circular surface is open, and the top circular surface is provided with transverse distribution grids parallel to each other; the central axis of the air inlet filter pipe is coaxially arranged with the central axis of the vortex chamber, and the bottom circular surface of the air inlet filter pipe is tightly attached to the ring-shaped flat plate of the transverse flow straightener.

[0014] Further, the observation column is a transparent hollow cylinder, and the upper and lower sides are open. A longitudinal square gap is opened on the circular ring surface as a sealing groove. Longitudinal long square sealing bosses are arranged on the two sides of the circular surface of the sealing groove. Longitudinal sealing screw holes are uniformly arranged on the two sealing bosses. The positions of the sealing screw holes on the two sealing bosses correspond to each other horizontally. The observation column axis is coaxially arranged with the vortex chamber axis, and the bottom surface of the observation column is tightly attached to the top surface of the air inlet filter pipe.

[0015] Further, the exhaust filter screen is a hollow cylinder, and the bottom surface is open. A grid is arranged on the top surface in a transverse distribution. A through hole is arranged in the center of the top surface as a static hole. The exhaust filter screen axis is coaxially arranged with the vortex chamber axis, and the bottom surface of the exhaust filter screen is tightly attached to the top surface of the observation column.

[0016] Further, the static dropper is a transparent hollow long cylinder, and the bottom surface is open. A through hole is arranged in the center of the top surface as a dropper hole. The static dropper can be placed into the static hole on the exhaust filter screen, and the bottom surface of the static dropper coincides with the bottom surface of the exhaust filter screen.

[0017] Further, the automatic injector is a product composed of an injection pump and an injector, which has the function of uniformly and slowly pushing a proper mass of liquid into an injection tube. An injection hole is arranged on the automatic injector.

[0018] Further, the injection tube is a circular tube, which is shaped to adapt to the test environment. One end of the injection tube is placed into the dropper hole on the static dropper, and the other end is placed into the injection hole on the automatic injector.

[0019] Further, the sensor sealing column is a column with a "convex" cross section. A through hole is arranged in the center of the sensor sealing column as a sensor hole. Through holes are arranged on the two sides of the sensor sealing column as sealing through holes. A plurality of sensor sealing columns are placed into the sealing groove and arranged horizontally and longitudinally from top to bottom. Bolts are used to fasten the sensor sealing columns to the observation column through the sealing through holes and the sealing screw holes.

[0020] Further, the sensor includes a pressure sensor and a temperature sensor, which can measure physical characteristics at corresponding positions in the flow field. The sensor can be placed into the sensor hole of the sensor sealing column, and the measurement end of the sensor is close to the vortex chamber axis. The observation column, the sensor sealing column, and the sensor realize the sealing of the internal space of the observation column.

[0021] Compared with the prior art, the liquid droplet evaporation test bench with known flow field parameters has the following advantages:

[0022] (1) The liquid droplet evaporation test bench with known flow field parameters provided an obvious observable air flow environment, reduced the error in the research results caused by uncontrollable and unmeasurable weak air flow disturbance around the liquid droplet in general equipment, and could study the evaporation characteristics of a single liquid droplet under transcritical / supercritical conditions in an environment with known flow field parameters, thereby improving the accuracy and repeatability of the test, and reducing the economic cost and time cost of operation in the test.

[0023] (2) The liquid droplet evaporation test bench with known flow field parameters, because the static dropper and the observation column in the equipment provided static and dynamic flow field environments respectively, the comparison of the movement state of the fuel droplet in the two can study the stability and evolution process of the transcritical / supercritical jet mixing layer. It has the characteristics of convenient research and improves the adaptability of the research process. BRIEF DESCRIPTION OF DRAWINGS

[0024] The drawings constituting a part of this application are used to provide a further understanding of the application, the illustrative embodiments of the application and the description thereof serve to explain the application, and do not constitute an improper limitation on the application. In the drawings:

[0025] Figure 1 The overall structure schematic view of the liquid droplet evaporation test bench with known flow field parameters described in the application;

[0026] Figure 2 The overall structure sectional view of the liquid droplet evaporation test bench with known flow field parameters described in the application;

[0027] Figure 3 The overall structure schematic view of the vortex chamber of the liquid droplet evaporation test bench with known flow field parameters described in the application;

[0028] Figure 4 The sectional view of the vortex chamber of the liquid droplet evaporation test bench with known flow field parameters described in the application along the air inlet column;

[0029] Figure 5 The sectional view of the vortex chamber of the liquid droplet evaporation test bench with known flow field parameters described in the application along the air outlet column;

[0030] Figure 6 The schematic view of the exhaust valve of the liquid droplet evaporation test bench with known flow field parameters described in the application;

[0031] Figure 7 The overall schematic view of the annular flow straightener net of the liquid droplet evaporation test bench with known flow field parameters described in the application;

[0032] Figure 8 The sectional view of the annular flow straightener net of the liquid droplet evaporation test bench with known flow field parameters described in the application along the central axis of the annular flow straightener net;

[0033] Figure 9 A top view of the circumferential fairing of a flow field parameter known droplet evaporation test bench according to the present application;

[0034] Figure 10 A schematic diagram of the transverse fairing of a flow field parameter known droplet evaporation test bench according to the present application;

[0035] Figure 11 A cross-sectional view along the central axis of the transverse fairing of a flow field parameter known droplet evaporation test bench according to the present application;

[0036] Figure 12 A top view of the transverse fairing of a flow field parameter known droplet evaporation test bench according to the present application;

[0037] Figure 13 A schematic diagram of the air inlet filter tube of a flow field parameter known droplet evaporation test bench according to the present application;

[0038] Figure 14 A cross-sectional view along the central axis of the air inlet filter tube of a flow field parameter known droplet evaporation test bench according to the present application;

[0039] Figure 15 A top view of the air inlet filter tube of a flow field parameter known droplet evaporation test bench according to the present application;

[0040] Figure 16 A schematic diagram of the observation column of a flow field parameter known droplet evaporation test bench according to the present application;

[0041] Figure 17 A cross-sectional view along the central axis of the observation column of a flow field parameter known droplet evaporation test bench according to the present application;

[0042] Figure 18 A cross-sectional view along the sealed screw hole of the observation column of a flow field parameter known droplet evaporation test bench according to the present application;

[0043] Figure 19 A schematic diagram of the sensor sealing column of a flow field parameter known droplet evaporation test bench according to the present application;

[0044] Figure 20 A cross-sectional view along the sealed through hole of the sensor sealing column of a flow field parameter known droplet evaporation test bench according to the present application;

[0045] Figure 21 A schematic diagram of the sensor of a flow field parameter known droplet evaporation test bench according to the present application;

[0046] Figure 22 Figure 1 is a schematic diagram of the overall view of the exhaust filter screen of a droplet evaporation test bench with known flow field parameters according to the present application;

[0047] Figure 23 Figure 2 is a sectional view along the central axis of the exhaust filter screen of a droplet evaporation test bench with known flow field parameters according to the present application;

[0048] Figure 24 Figure 3 is a top view of the exhaust filter screen of a droplet evaporation test bench with known flow field parameters according to the present application;

[0049] Figure 25 Figure 4 is a schematic diagram of the overall view of the automatic injector of a droplet evaporation test bench with known flow field parameters according to the present application;

[0050] Figure 26 Figure 5 is a schematic diagram of the overall view of the injection capillary tube of a droplet evaporation test bench with known flow field parameters according to the present application;

[0051] Figure 27 Figure 6 is a sectional view of the injection capillary tube of a droplet evaporation test bench with known flow field parameters according to the present application;

[0052] Figure 28 Figure 7 is a schematic diagram of the overall view of the static dropper of a droplet evaporation test bench with known flow field parameters according to the present application;

[0053] Figure 29 Figure 8 is a sectional view along the dropper hole of the static dropper of a droplet evaporation test bench with known flow field parameters according to the present application.

[0054] BRIEF DESCRIPTION OF THE DRAWINGS

[0055] 1, observation column; 11, sealing through slot; 12, central axis of observation column; 13, sealing boss; 131, sealing screw hole; 2, air inlet filter tube; 21, central axis of air inlet filter tube; 3, transverse flow straightener; 31, hemispherical sheet of transverse flow straightener; 32, annular flat sheet of transverse flow straightener; 33, central axis of transverse flow straightener; 4, annular flow straightener; 41, hemispherical sheet of annular flow straightener; 42, annular flat sheet of annular flow straightener; 43, central axis of annular flow straightener; 5, vortex chamber; 51, central axis of vortex chamber; 52, air outlet column; 521, air outlet hole; 53, air inlet column; 531, air inlet hole; 54, cylindrical surface of vortex chamber; 6, air outlet valve; 7, exhaust filter screen; 71, static hole; 72, central axis of exhaust filter screen; 8, static dropper; 81, dropper hole; 9, injection capillary tube; 10, automatic injector; 1010, injection hole; 111, sensor sealing column; 1110, sealing through hole; 1120, sensor hole; 112, sensor; 1210, measurement end of sensor. DETAILED DESCRIPTION

[0056] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other in the case of no conflict.

[0057] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0058] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.

[0059] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0060] In order to realize a more efficient and low-pollution engine, high injection pressure, high supercharging, high back pressure and other technical measures are widely used, so that the in-cylinder temperature and back pressure approach and exceed the critical point of fuel, which is not a small probability phenomenon, so that trans-critical / supercritical spray mixing becomes an unavoidable problem for the engine. In the critical case, the liquid phase density decreases significantly, and the gas-liquid interface is difficult to identify, and instead a gas-liquid two-phase mixing layer mainly controlled by diffusion process appears, which is due to the disappearance of liquid surface tension and the increase of gas-liquid interface thickness. Therefore, the disintegration of liquid jet and the formation of mixed gas are no longer controlled by surface tension and aerodynamic instability, but by turbulent diffusion process. At this time, a weak disturbance on the gas-liquid interface can have a great influence on the diffusion process of the fuel.

[0061] For a long time, the research on trans-critical / super-critical spray mainly focuses on three aspects. The first is the evaporation characteristics of single droplet under trans-critical / super-critical conditions. The second is the calculation method of the state equation, thermophysical properties and transport coefficients of real fluid under trans-critical / super-critical conditions. The third is the stability and evolution process of trans-critical / super-critical jet mixing layer. The existing experimental methods, such as the main work in constant volume bomb, are to study the jet situation of the spray, which can provide experimental data for the second point. However, because the constant volume bomb can only ensure that the flow field environment is approximately static relative to the dynamic process of the spray, but the weak air flow disturbance caused by temperature transfer is difficult to control and measure, and this will cause larger data result error due to the characteristics of trans-critical / super-critical spray.

[0062] The weak air flow disturbance is difficult to observe and control, but if a clearly observable air flow environment is artificially provided, the flow field parameters of the air flow can be observed, and the accidental air flow disturbance can also be predicted and controlled. In this way, the error and unknown situation in the research results caused by the uncontrolled and unmeasurable weak air flow disturbance determined by the disappearance of liquid surface tension and the increase of gas-liquid interface thickness under trans-critical / super-critical conditions can be reduced, and the evaporation characteristics of single droplet under trans-critical / super-critical conditions can be studied in an environment where the flow field parameters are known. At the same time, because the static dropper and the observation column in the device provide static and dynamic flow field environments respectively, the comparison of the motion state of fuel droplets in the two can study the stability and evolution process of trans-critical / super-critical jet mixing layer.

[0063] As shown in Figure 1 and Figure 2 , a droplet evaporation test bench with known flow field parameters, characterized in that it comprises an observation column 1, which is tightly connected with a vortex chamber 5 through an air inlet filter pipe 2, a transverse flow straightener net 3, a ring flow straightener net 4. An air exhaust valve 6 is installed in the air exhaust hole 521 of the vortex chamber 5. The observation column 1 is tightly connected with an air exhaust filter net 7. A static dropper 8 is installed in the static hole 71 in the center of the air exhaust filter net 7. A fine injection tube 9 is connected with the injection hole 1010 of an automatic injector 10 at one end and connected with the dropper hole 81 of the static dropper 8 at the other end. A plurality of sensor sealing columns 111 are installed in the sealing through slot 11 on the observation column 1, and a sensor 112 is installed in the sensor hole 1120 of the sensor sealing column 111.

[0064] As shown in Figure 3 , Figure 4 and Figure 5The vortex chamber 5 is a hollow cylinder with a circular top opening. A square-section air inlet column 53 is tangentially arranged on the cylinder wall of the vortex chamber 5. The air inlet column 53 has a square-section air inlet hole 531, and the inner wall of the air inlet hole 531 is also tangential to the inner wall of the vortex chamber 5. A certain mass flow of air enters the vortex chamber 5 through the air inlet hole 531. In order to provide an orderly and controllable flow field environment in the observation column, the air flow is first made to form a preliminary orderly state, i.e. vortex, in the vortex chamber 5. The bottom center of the vortex chamber 5 is provided with a cylinder, which is an air outlet column 52. The air outlet column 52 is centrally provided with an air outlet hole 521. As shown in Figure 6 , the air outlet valve 6 is a product with the functions of controlling the on-off of air flow and the speed of air flow. The air outlet valve 6 is just placed in the air outlet hole 521 in the center of the air outlet column 52 of the vortex chamber 5. The air outlet valve 6 can discharge a certain mass flow of air out of the vortex chamber 5, so as to control the mass flow of air entering the observation column 1.

[0065] As shown in Figure 7 , Figure 8 and Figure 9 , the annular flow straightener 4 is a semispherical sheet with a ring-shaped flat plate at the bottom. When viewed from above, the grid of the annular flow straightener 4 is arranged in an annular distribution. The vortex velocity formed in the vortex chamber 5 presents a radial non-uniform distribution characteristic: the closer to the outside, the greater the air flow velocity, and the closer to the inside, the smaller the air flow velocity. This is the reason why the air outlet column 52 is arranged at the center of the bottom of the vortex chamber 5, because the air flow velocity in the center is the smallest, and the air can be stably discharged without affecting the movement of the vortex. The central axis of the annular flow straightener 4 is coaxially arranged with the central axis of the vortex chamber 5, the semispherical sheet is convex upward, and the ring-shaped flat plate of the annular flow straightener 4 is tightly attached to the top flat plate of the vortex chamber 5. Since the flow velocity is greater near the outside of the vortex chamber 5, the grid of the annular flow straightener 4 is arranged in an annular distribution and in a semispherical shape, so that the flow with a large velocity first contacts the flow straightener at the periphery and changes the velocity distribution, and the flow with a small velocity finally contacts the flow straightener at the center, thereby forming a flow field with uniform velocity distribution along the axial direction.

[0066] As shown in Figure 10 , Figure 11 and Figure 12As shown, the transverse rectifier net 3 is a semispherical sheet with a ring-shaped flat plate at the bottom. When viewed from above, the transverse rectifier net 3 is arranged with the grids parallel to each other. The axis of the transverse rectifier net 3 is coaxial with the axis of the vortex chamber 5, and the semispherical sheet is convex upward, with the ring-shaped flat plate of the transverse rectifier net 3 abutting the ring-shaped flat plate of the annular rectifier net 4. The airflow from the annular rectifier net 4 is uniformly distributed in the axial direction, but the distribution of the horizontal velocity is chaotic. Since the vortex is larger closer to the periphery, the airflow from the annular rectifier net 4 is more chaotic closer to the periphery. Therefore, the transverse rectifier net 3 is arranged in a semispherical shape with the grids parallel to each other in the transverse direction. The more chaotic the airflow, the earlier it contacts the transverse rectifier net 3, and the earlier and more intense the vortex component in the airflow can be removed, so that the airflow from the transverse rectifier net 3 is also uniformly distributed in the horizontal direction.

[0067] As shown in Figure 13 , Figure 14 and Figure 15 , the air inlet filter tube 2 is a hollow cylinder with an open bottom circular face and a top circular face provided with grids parallel to each other in the transverse direction. The axis of the air inlet filter tube 2 is coaxial with the axis of the vortex chamber 5, and the bottom circular face of the air inlet filter tube 2 abuts the ring-shaped flat plate of the transverse rectifier net 3. The airflow from the transverse rectifier net 3 is further stabilized in the air inlet filter tube 2, with the airflow closer to the periphery taking longer to stabilize. Finally, the airflow is further filtered in the transversely distributed grids, so that the airflow finally entering the observation column 1 can be uniformly and stably distributed in all directions.

[0068] The airflow from the air inlet filter tube 2 into the observation column 1 is uniformly and stably distributed in all directions on the same horizontal plane, with airflow disturbance being minimized. As shown in Figure 16 , Figure 17 and Figure 18 , the observation column 1 is a transparent hollow cylinder with open circular faces on both the top and bottom. A longitudinal square slot is formed in the circular annular face as a sealing groove 11, and longitudinal strip-shaped sealing bosses 13 are provided on the circular faces on both sides of the sealing groove 11. The sealing bosses 13 on both sides are provided with sealing screw holes 131 uniformly in the longitudinal direction, and the positions of the sealing screw holes 131 on the sealing bosses 13 on both sides correspond to each other horizontally. The axis of the observation column 1 is coaxial with the axis of the vortex chamber 5, and the bottom face of the observation column 1 abuts the top face of the air inlet filter tube 2. As shown in Figure 19 and Figure 20As shown, the sensor 112 sealing column 111 is a column with a convex cross section. A through hole 1120 is set in the center of the sensor 112 sealing column 111 along its transverse direction. Through holes 1110 are set in the transverse direction on both sides of the sensor 112 sealing column 111. Several sensor 112 sealing columns 111 fit neatly into the sealing groove 11 and are arranged horizontally and longitudinally from top to bottom. Bolts pass through the sealing through hole 1110 and the sealing screw hole 131 to fasten the sensor 112 sealing column 111 to the observation column 1. Figure 21 As shown, the sensor 112 is a general term for a class of products, including pressure sensors 112, temperature sensors 112, etc., which can measure physical characteristics at corresponding positions in the flow field. The sensor 112 can be placed just in the sensor 112 hole 1120 of the sensor 112 sealing column 111. The measuring end of the sensor 112 is close to the central axis of the vortex chamber 5. The observation column 1, the sensor 112 sealing column 111 and the sensor 112 seal the internal space of the observation column 1. At different positions inside the observation column 1 near the central axis, the local pressure and temperature are measured by the measuring end of the sensor 112. The local density and velocity can be calculated based on the Clapeyron equation and the Bernoulli equation. The mass flow rate of the airflow entering the observation column 1 is known. Therefore, the flow field parameters such as the pressure, temperature, density and velocity of the airflow near the central axis inside the observation column 1 are all known. In this way, a clearly observable airflow environment can be artificially provided, and the flow field parameters of the airflow can be observed. The accidental airflow disturbances can also be predicted and controlled. The evaporation characteristics of a single droplet under transcritical / supercritical conditions can be studied in an environment where the flow field parameters are known.

[0069] like Figure 22 、 Figure 23 and Figure 24 The exhaust filter 7 is a hollow cylinder with an open bottom circular surface and a horizontally distributed grid pattern on the top circular surface. A through hole 71 is provided in the center of the top circular surface. The central axis of the exhaust filter 7 is coaxial with the central axis of the vortex chamber 5, and the bottom surface of the exhaust filter 7 is in close contact with the top surface of the observation column 1. Airflow passing through the observation column 1 flows out of the exhaust filter 7 in a timely manner, avoiding unnecessary disturbance caused by airflow accumulation.

[0070] like Figure 25 As shown, the automatic syringe 10 is a product consisting of a syringe pump and a syringe, which has the function of evenly and slowly pushing a liquid of appropriate mass into the syringe tube 9. There is an injection hole 1010 on the automatic syringe 10. Figure 26 and Figure 27 As shown, the injection tube 9 is a round tube, and its shape is adapted to the test environment. One end of the injection tube 9 is just placed in the dropper hole 81 on the static dropper 8, and the other end is just placed in the injection hole 1010 on the automatic injector 10. Figure 28 andFigure 29 As shown, the static drop tube 8 is a transparent hollow long cylinder, with a bottom circular face opening and a through hole in the center of the top circular face as the drop tube hole 81. The static drop tube 8 can be just put into the static hole 71 on the exhaust filter screen 7, and the bottom face of the static drop tube 8 coincides with the bottom face of the exhaust filter screen 7. A certain mass of fuel drops into the static drop tube 8 from the automatic injector 10 through the injection capillary tube 9, and since the inside of the static drop tube 8 is sealed, it can be considered that the inside of the static drop tube 8 is a static gas environment; when the fuel droplets fall out of the bottom face of the static drop tube 8, which coincides with the bottom face of the exhaust filter screen 7, they begin to be affected by the airflow. The static drop tube 8 and the observation column 1 in the device provide static and dynamic flow field environments respectively, so the comparison of the motion state of the fuel droplets in the two can study the stability and evolution process of the trans-critical / supercritical jet mixing layer.

[0071] The installation method and functional implementation process of the liquid droplet evaporation test bench with known flow field parameters of the present application are as follows:

[0072] The exhaust valve 6 can be just put into the exhaust hole 521 in the center of the exhaust column 52 of the vortex chamber 5.

[0073] The axis of the annular flow straightener 4 is coaxially arranged with the axis of the vortex chamber 5, the semispherical thin plate protrudes upward, and the annular plane plate of the annular flow straightener 4 tightly abuts the top plane of the vortex chamber 5.

[0074] The axis of the transverse flow straightener 3 is coaxially arranged with the axis of the vortex chamber 5, the semispherical thin plate protrudes upward, and the annular plane plate of the transverse flow straightener 3 tightly abuts the annular plane plate of the annular flow straightener 4.

[0075] The axis of the inlet filter tube 2 is coaxially arranged with the axis of the vortex chamber 5, and the bottom circular face of the inlet filter tube 2 tightly abuts the annular plane plate of the transverse flow straightener 3.

[0076] The axis of the observation column 1 is coaxially arranged with the axis of the vortex chamber 5, and the bottom face of the observation column 1 tightly abuts the top face of the inlet filter tube 2.

[0077] The sensor 112 sealing column 111 is just put into the sealing through slot 11, and the sensors 112 are arranged horizontally and longitudinally from top to bottom, and the sensor 112 sealing column 111 is fastened to the observation column 1 by bolts through the sealing through hole 1110 and the sealing screw hole 131.

[0078] The sensor 112 can be just put into the sensor 112 hole 1120 of the sensor 112 sealing column 111, and the measurement end of the sensor 112 is close to the vicinity of the axis of the vortex chamber 5, and the observation column 1, the sensor 112 sealing column 111 and the sensor 112 realize the sealing of the internal space of the observation column 1.

[0079] The axis of the exhaust filter screen 7 is coaxially arranged with the axis of the vortex chamber 5, and the bottom face of the exhaust filter screen 7 tightly abuts the top face of the observation column 1.

[0080] The end of the injection tube 9 is just placed into the dropper hole 81 on the static dropper 8, and the other end is just placed into the injection hole 1010 on the automatic injector 10.

[0081] The static dropper 8 can be just placed into the static hole 71 on the exhaust filter screen 7, and the bottom surface of the static dropper 8 is coincident with the bottom surface of the exhaust filter screen 7. Thus, the installation of the liquid droplet evaporation test bench with known flow field parameters is completed.

[0082] The air with a certain mass flow rate enters the vortex chamber 5 from the air inlet hole 531, and in order to finally provide an orderly and controllable flow field environment in the observation column, the air flow is first made to form a preliminary orderly state, i.e., vortex, in the vortex chamber 5.

[0083] Because the air flow rate in the center of the vortex chamber 5 is the smallest, the air can be stably discharged without affecting the movement of the vortex, so the air discharge column 52 and the exhaust valve 6 are arranged at the center of the bottom of the vortex chamber 5. The exhaust valve 6 is a product with the functions of controlling the on-off of the air flow and the flow rate of the air flow. The exhaust valve 6 can discharge the air with a certain mass flow rate out of the vortex chamber 5, so as to control the mass flow rate of the air finally entering the observation column 1.

[0084] The vortex velocity formed in the vortex chamber 5 presents a radial uneven distribution characteristic: the closer to the outside, the greater the air flow rate, and the closer to the inside, the smaller the air flow rate, so the grid of the annular flow regulating screen 4 is arranged in an annular distribution and in a hemispherical shape, so that the air flow with a large flow rate first contacts the flow regulating screen at the periphery and changes the velocity distribution, and the air flow with a small flow rate finally contacts the flow regulating screen at the center, so as to form a flow field with a uniform velocity distribution in the axial direction.

[0085] The air flow out of the annular flow regulating screen 4 has a uniform velocity distribution in the axial direction, but the velocity distribution in the horizontal direction is chaotic, and because the vortex is greater closer to the periphery, the air flow out of the annular flow regulating screen 4 is more chaotic closer to the periphery, so the transverse flow regulating screen 3 is arranged in a hemispherical shape and the grid is distributed in parallel in the transverse direction, the more chaotic air flow contacts the transverse flow regulating screen 3 earlier, so that the vortex component in the air flow can be removed earlier and more intensively, and the air flow out of the transverse flow regulating screen 3 is also uniformly distributed in the horizontal direction.

[0086] The air flow out of the transverse flow regulating screen 3 is further stabilized in the air inlet filter tube 2, and the air flow closer to the periphery is stabilized for a longer time, and finally further filtered in the transversely distributed grid, so that the air flow finally entering the observation column 1 can be uniformly and stably maintained in all directions.

[0087] The gas flow from the air inlet filter pipe 2 into the observation column 1 is evenly and stably distributed in all directions of the same horizontal plane, and the disturbance of the gas flow is maximally eliminated. The sensor 112 is a general term for a kind of products, including a pressure sensor 112, a temperature sensor 112 and the like, which can measure the physical characteristics at the corresponding position in the flow field. The local pressure and temperature are measured by the measuring end of the sensor 112 at different positions near the central axis inside the observation column 1, and the mass flow of the gas flow into the observation column 1 is known, so the local density and velocity can be calculated according to the Clapeyron equation and the Bernoulli equation, and therefore the flow field parameters such as the pressure, temperature, density and velocity of the gas flow near the central axis inside the observation column 1 are known. Thus an obviously observable gas flow environment can be artificially provided, and the flow field parameters of the gas flow can be observed at this time, the disturbance of the gas flow caused by chance can also be predicted and controlled, and the evaporation characteristics of a single droplet under transcritical / supercritical conditions can be studied in an environment where the flow field parameters are known.

[0088] The gas flow through the observation column 1 is timely discharged from the exhaust filter screen 7, so as to avoid unnecessary disturbance caused by accumulation of the gas flow.

[0089] The automatic injector 10 is a product composed of an injection pump and an injector, and has the function of uniformly and slowly propelling a liquid of proper mass into the injection fine tube 9. The fuel of a certain mass is finally dropped into the static dropper 8 from the automatic injector 10 through the injection fine tube 9, and since the inside of the static dropper 8 is sealed, it can be considered that the inside of the static dropper 8 is a static gas environment; and when the fuel droplet falls out of the bottom surface of the static dropper 8, which coincides with the bottom surface of the exhaust filter screen 7, the fuel droplet begins to be affected by the gas flow. The static dropper 8 and the observation column 1 in the device respectively provide static and dynamic flow field environments, so the comparison of the motion states of the fuel droplet in the two can study the stability and evolution process of the transcritical / supercritical jet mixing layer. Thus the description of the function realization process of the liquid droplet evaporation test bed with known flow field parameters is completed.

[0090] The above only describes the preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A droplet evaporation test bench with known flow field parameters, characterized in that: It comprises an observation column, an air inlet filter tube, a horizontal rectifier net, a ring rectifier net, a vortex chamber, an air outlet valve, an air outlet filter net, a static dropper, an injection tube and an automatic injector. One end of the observation column is fastened with the vortex chamber through the air inlet filter tube, the horizontal rectifier net and the ring rectifier net. The other end of the observation column is fastened with the air outlet filter net, the static dropper is installed in the static hole of the air outlet filter net, one end of the injection tube is connected with the injection hole of the automatic injector and the other end is connected with the dropper hole of the static dropper, a plurality of sensor sealing columns are installed in the sealing through slot on the observation column, and the sensors are installed in the sensor holes of the sensor sealing columns. The vortex chamber is in the shape of a hollow cylinder with an open top circular surface. The ring rectifier net is a semispherical sheet with a ring flat plate at the bottom. The horizontal rectifier net is a semispherical sheet with a ring flat plate at the bottom. The air inlet filter tube is a hollow cylinder with an open bottom circular surface and a top circular surface provided with horizontally distributed grids. The observation column is a transparent hollow cylinder with open upper and lower circular surfaces.

2. The droplet evaporation test bench with known flow field parameters according to claim 1, characterized in that: The air outlet filter net is a hollow cylinder with an open bottom circular surface and a top circular surface provided with horizontally distributed grids.

3. The droplet evaporation test bench with known flow field parameters according to claim 1, characterized in that: The static dropper is a transparent hollow long cylinder with an open bottom circular surface and a top circular surface provided with a dropper hole in the center.

4. The droplet evaporation test bench with known flow field parameters according to claim 1, characterized in that: The automatic injector is a product composed of an injection pump and an injector.

5. The droplet evaporation test bench with known flow field parameters according to claim 4, characterized in that: The injection tube is a circular tube with a shape suitable for the test environment.

6. The droplet evaporation test bench with known flow field parameters according to claim 1, characterized in that: The sensor sealing column is a column with a "convex" cross section, a through hole is arranged in the center of the sensor sealing column along the transverse direction to form a sensor hole, and through holes are arranged on both sides of the sensor sealing column along the transverse direction to form sealing through holes; a plurality of sensor sealing columns are arranged in the sealing through groove and arranged horizontally and longitudinally from top to bottom, and bolts pass through the sealing through holes and sealing screw holes to fasten the sensor sealing columns on the observation column.

7. The droplet evaporation test bench with known flow field parameters according to claim 6, characterized in that: The sensor includes a pressure sensor and a temperature sensor, and can measure physical characteristics at corresponding positions in a flow field; the sensor can be arranged in the sensor hole of the sensor sealing column, and a measurement end of the sensor is close to the axis in the vortex chamber; the observation column, the sensor sealing column and the sensor realize sealing of the internal space of the observation column.

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