阅读说明：本技术 带有蜗壳螺旋式二次流的引射器装置 (Ejector device with spiral volute secondary flow ) 是由 杜青 刘展睿 焦魁 于 2019-08-30 设计创作，主要内容包括：本发明公开了一种带有蜗壳螺旋式二次流的引射器装置,在混合室外的轴线上设有一次流入口管,在混合室径向设置两个对称的蜗壳螺旋式二次流入口管,两个二次流入口管以圆弧线环绕贴合在混合室表面,并与混合室相通。一次流与二次流三股流体在混合室内合为一体,依次进入混合管、扩散管,最终通过出口管离开引射器。在蜗壳与壁面接触之后,用蜗壳的外壁作为混合室的壁面。入口管的蜗壳旋转角度为160°,蜗壳螺旋式的环状结构使气流沿壁面逐渐进入引射器,起到了引导气流运动的作用。本发明能够有利于引射器内部的气流均匀分布,减少传统引射器结构二次流撞击壁面所引起的能量损失,有效提高了引射器性能。(The invention discloses an ejector device with spiral secondary flow of a volute, wherein a primary flow inlet pipe is arranged on an axis outside a mixing chamber, two symmetrical spiral secondary flow inlet pipes of the volute are radially arranged in the mixing chamber, and the two secondary flow inlet pipes are attached to the surface of the mixing chamber in a surrounding manner by an arc line and are communicated with the mixing chamber. The three flows of the primary flow and the secondary flow are integrated in the mixing chamber, sequentially enter the mixing pipe and the diffusion pipe, and finally leave the ejector through the outlet pipe. After the volute is in contact with the wall surface, the outer wall of the volute is used as the wall surface of the mixing chamber. The spiral case rotation angle of the inlet pipe is 160 degrees, the spiral annular structure of the spiral case enables airflow to gradually enter the ejector along the wall surface, and the effect of guiding the airflow to move is achieved. The invention can be beneficial to the uniform distribution of air flow in the ejector, reduces the energy loss caused by the impact of secondary flow on the wall surface of the traditional ejector structure and effectively improves the performance of the ejector.)

1. Ejector device with spiral secondary flow of spiral case, the ejector comprises primary flow inlet pipe, secondary flow inlet pipe, convergent spray tube mixing chamber, hybrid tube and diffuser, its characterized in that: be equipped with primary flow inlet pipe (3) on the axis outside mixing chamber (1), spiral secondary flow inlet pipe (2-1, 2-2) of spiral case of two symmetries are radially set up to the mixing chamber, two secondary flow inlet pipes encircle the laminating on the mixing chamber surface with the circular arc line, and communicate with each other with the mixing chamber, primary flow fluid gets into convergent spray tube (4) in the ejector through primary flow inlet pipe, secondary flow fluid gets into the mixing chamber from two imports, primary flow and secondary flow three strand fluid are as an organic whole in the mixing chamber, get into mixing tube (5) in proper order, diffuser (6), finally leave the ejector through outlet pipe (7).

2. The eductor apparatus with spiral-wound secondary flow according to claim 1 wherein: and taking the central line of the mixing pipe as an axis, wherein the spiral rotation angles of the inlet sections of the two spiral volute secondary flow inlet pipes are both 160 degrees, and the inlet positions of the two spiral volute secondary flow inlet pipes are 180 degrees symmetrical.

3. The eductor apparatus with spiral-wound secondary flow according to claim 1 wherein: the two spiral volute secondary flow inlet pipes have the same structural size.

4. The eductor apparatus with spiral-type secondary flow in the volute of claim 1 wherein the inlet cross-section of the two spiral-type secondary flow inlet pipes can be rectangular, square, triangular, or parallelogram.

Technical Field

The invention belongs to the field of fluid mechanics, and particularly relates to a device for ejecting low-pressure fluid by using the energy of high-pressure fluid.

Background

The ejector is an energy conversion device, and is frequently utilized by people due to the characteristics of no moving part, small volume, simple maintenance, low noise in working and the like. The ejector ejects low-pressure fluid by using the energy of high-pressure (liquid, gas or mixed fluid) fluid according to the fluid mechanics principle, and the working principle of the ejector is shown in fig. 1. The traditional ejector consists of a primary flow inlet pipe, a secondary flow inlet pipe, a reducing spray pipe, a mixing chamber, a mixing pipe and a diffusion pipe. When the primary flow high-pressure fluid passes through the tapered nozzle through the inlet pipe, negative pressure is generated at the outlet of the tapered nozzle (namely, in the mixing pipe) due to the fact that the area is reduced and the pressure is reduced, the larger the pressure difference generated by the primary flow inlet fluid in the tapered section is, the larger the negative pressure in the mixing pipe is, and the larger the pressure difference between the secondary flow inlet and the mixing pipe is. The secondary flow is entrained into the eductor by this pressure differential. The primary flow and the secondary flow are intersected in the mixing chamber and flow to the mixing pipe, the mixing process is further completed in the mixing pipe, and the pressure and the speed of the mixed fluid are gradually stabilized. The ejector diffusion tube is used for converting kinetic energy into pressure potential energy. Since the area of the diffuser pipe gradually increases, the velocity of the high-velocity mixed fluid gradually decreases and the pressure gradually increases.

The defects of the ejector structure are as follows: different condition parameters of the external fluid can have a great influence on the performance of the ejector. Generally, when the pressure of the primary flow fluid at an inlet is lower, the pressure difference generated at the tapered section is relatively small, and the performance of the ejector is greatly reduced. Therefore, for fluids with relatively low inlet pressures, it is not suitable for conversion to kinetic energy using an ejector. If the structure of the ejector is changed, the ejector still has good working efficiency at low pressure, which is a good measure for improving the performance of the ejector and can expand the application and working range of the ejector.

Disclosure of Invention

The invention aims to provide an ejector device with volute type secondary flow by improving the structure of the existing ejector and optimizing the design of a secondary flow inlet pipe.

The technical principle and the structural scheme of the invention are explained as follows:

the ejector device with spiral volute secondary flow consists of a primary flow inlet pipe, a secondary flow inlet pipe, a reducing spray pipe, a mixing chamber, a mixing pipe and a diffusion pipe. The improvement scheme is as follows: be equipped with the primary flow inlet pipe on the outer axis of mixing chamber, set up the spiral secondary flow inlet pipe of spiral case of two symmetries radially at the mixing chamber, two secondary flow inlet pipes encircle the laminating on the mixing chamber surface with the arc line to communicate with each other with the mixing chamber. The primary flow fluid enters a reducing spray pipe in the ejector through a primary flow inlet pipe, and the secondary flow fluid enters the mixing chamber from two inlets. The three flows of the primary flow and the secondary flow are integrated in the mixing chamber, sequentially enter the mixing pipe and the diffusion pipe, and finally leave the ejector through the outlet pipe.

The inlet pipe of the secondary flow adopts a spiral shell type rotary double-inlet structural design. The structure is two symmetrical volute inlets surrounding the mixing chamber pipe. The spiral volute adopts a structure of being attached to a wall surface, after the volute is contacted with the wall surface, the wall surface of an original mixing chamber is replaced by the outer wall of the volute, and airflow enters the mixing chamber of the ejector while rotating.

The spiral volute can strengthen the technical characteristics of fluid disturbance that a symmetrical inlet can generate two opposite airflow movements, the acting forces in the flowing directions are mutually offset, and the spiral annular structure of the volute enables the airflow to gradually enter a mixing chamber along the wall surface. The uniform distribution of airflow in a mixing chamber in the ejector is facilitated, and the energy loss caused by secondary flow impacting a wall surface of a typical ejector structure is reduced.

The invention has the characteristics and beneficial effects that: the spiral secondary flow ejector of the volute can effectively reduce the loss of fluid impact wall surface caused by the traditional ejector, and the spiral structure of the volute plays a role in gas diversion. Make the water conservancy diversion gas flow along the wall direction, the inside gas flow's of reinforcing ejector homogeneity makes the inside primary flow of ejector and the mixing between the secondary flow more abundant, plays the promotion effect to the formation in vacuum area simultaneously. Therefore, the attracted amount of the secondary flow is effectively improved, the performance of the ejector is improved, and the working range of the ejector is expanded.

The inlet shape design similar to a volute shape is adopted, so that the energy caused by pressure difference generated by high-pressure fluid can be more effectively utilized, the incoming flow motion track during air inlet is optimized, the incoming flow of secondary flow is more uniform, the mixing with primary flow is facilitated, the generated vacuum area is more uniform, and the vacuum degree is improved.

Drawings

Fig. 1 is a schematic diagram of an appearance structure of a conventional ejector.

Fig. 2 is a schematic appearance three-dimensional structure diagram of a spiral volute type secondary flow ejector device.

Fig. 3 is a front view of fig. 2 to illustrate an internal structure of the ejector.

FIG. 4 is a cross-sectional view of FIG. 2 illustrating the spiral of the volute around the interior of the eductor.

FIG. 5 is a graph comparing ejector reflux ratios according to embodiments of the present invention.

Detailed Description

The technical solution of the present invention is described in detail by specific embodiments with reference to the accompanying drawings. It should be noted that the present embodiments are illustrative rather than limiting and do not limit the scope of the invention.

The traditional or currently generally adopted ejector structure is shown in figure 1 and comprises a primary flow inlet pipe, a secondary flow inlet pipe, a reducing nozzle mixing chamber, a mixing pipe and a diffusion pipe.

The novel structure of the invention is as follows: a primary flow inlet pipe 3 is arranged on an axis outside the mixing chamber 1, two symmetrical spiral volute type secondary flow inlet pipes 2-1 and 2-2 are radially arranged in the mixing chamber, and the two secondary flow inlet pipes are attached to the surface of the mixing chamber in a surrounding mode through arc lines and are communicated with the mixing chamber. The primary flow fluid enters a reducing spray pipe 4 in the ejector through a primary flow inlet pipe, the secondary flow fluid enters a mixing chamber from two inlets, the primary flow and the secondary flow are combined into a whole in the mixing chamber, and the primary flow and the secondary flow sequentially enter a mixing pipe 5 and a diffusion pipe 6 and finally leave the ejector through an outlet pipe 7.

The spiral rotation angles of the inlet sections of the spiral secondary flow inlet pipes of the two spiral volutes are 160 degrees by taking the center line of the mixing chamber as the axis. The inlet positions of the two secondary flow inlet pipes are 180 degrees symmetrical. The air flow is guided to flow along the wall surface direction of the volute, and the uniform distribution of the air in the ejector is enhanced. The structural sizes of the two spiral volute secondary flow inlet pipes are the same. The inlet cross section of the two spiral volute secondary flow inlet pipes can be rectangular, and can also be square, triangular or parallelogram.

The ejector makes substantial optimization improvement on the structure of the secondary flow inlet pipe under the condition that other structures are not changed. The two volute type inlet pipes are symmetrically distributed, so that the uniformity of fluid flow can be improved. The cross section of the secondary inflow port is rectangular, the whole area contacted with the mixing chamber is taken as the outlet, and the rectangular cross section is not taken as the inlet, so that the design increases the area of the inlet air, and improves the uniformity of the inlet air.

As an example, the rectangular cross-section of the spiral volute inlet is 47mm in length and 31mm in width.

The diameter of the primary flow inlet tube was 27.6mm, the diameter of the outlet tube was 41.8mm, the diameter of the mixing tube was 18mm, the length was 117mm, the length of the diffuser tube was 170mm, the diameter of the mixing chamber was 70mm, the length of the nozzle was 116.5mm, and the throat diameter was 7.2 mm.

Compared with the implementation effect of the invention, the embodiment adopts 2 ejectors for comparison, wherein 1 ejector adopts the structure of the invention; the other 1 adopts the traditional ejector structure. The two ejectors have the same technical parameters and materials except for different structures.

The 2 ejectors were tested under the same conditions with primary stream gas from pure hydrogen in the hydrogen tank at pressures ranging from 325 to 450kPa and temperatures of 20 ℃. The secondary stream was humidified hydrogen at a pressure of 300kPa, a relative humidity of 80%, a temperature of 80 ℃ and an internal ambient pressure of 300 kPa.

Fig. 5 shows a comparison of the results of 2 ejector reflux ratio simulation calculations. The reflux ratio is the ratio of the flow of the attracted secondary flow to the flow of the primary flow and is used for indicating the performance of the ejector, and the performance of the ejector is better when the reflux ratio is larger. The spiral volute type ejector has the advantages that the performance of the ejector is remarkably improved, and particularly in a low primary flow pressure area, the reflux ratio of the ejector is effectively improved, and the working stability of the ejector is effectively improved.