CN112460979B

CN112460979B - Multistage central current-limiting type air supply grille

Info

Publication number: CN112460979B
Application number: CN202011323642.7A
Authority: CN
Inventors: 杨福胜; 李国嘉; 姜显智; 邵云帆; 王天润; 史钰普; 洪圣
Original assignee: Xian Jiaotong University
Current assignee: Xian Jiaotong University
Priority date: 2020-11-23
Filing date: 2020-11-23
Publication date: 2022-02-11
Anticipated expiration: 2040-11-23
Also published as: CN112460979A

Abstract

The invention discloses a multi-stage central current-limiting air supply grille, which is used for a divergent section in a hot air drying air supply channel and achieves the effects of enabling hot air to be uniformly distributed and improving the drying quality of materials through the current limiting and guiding of the air. The grid is formed by arranging hollow square stainless steel tubes according to the rule that the central area of the gradually-expanding section is arranged at equal intervals at small intervals and the areas at two sides are arranged at equal intervals at large intervals, so that the uniformity of air outlet at the outlet of the gradually-expanding section is obviously improved, the local vortex and backflow of air at the outlet of the gradually-expanding section are obviously reduced, and the grid is suitable for the condition that an expanding section is arranged in a ventilation pipeline, and an air supply channel is integrally short, so that the flowing condition of full development cannot be formed.

Description

Multistage central current-limiting type air supply grille

Technical Field

The invention relates to the field of hot air drying systems, in particular to a multi-stage central current-limiting air supply grille.

Background

After agricultural products such as grains and the like are harvested, the agricultural products are mildewed, germinated and deteriorated in storage, transportation, processing and other links due to the fact that the agricultural products are wet in climate, too late to be dried in the sun or not capable of achieving safe water storage, and unnecessary waste is caused. This requires timely and efficient drying of the harvested produce. Use hot-blast drying as the medium is the drying technique of taking extensively in the agricultural, hot-blast generating device's air outlet is narrower under most circumstances at present, and the air supply passageway between the drying chamber need increase the divergent section and make the material more evenly contact hot-blast, but because the space of leaving the air supply pipeline is limited, hot-blast flow is too late to reach the fully developed state, cause the local flow condition at the divergent section relatively poor, phenomenon such as vortex and backward flow appear, the homogeneity of air supply and material drying has been influenced. The defect causes that the drying effect and efficiency of the drying technology in the current market are lower, and the materials can not be dried uniformly. The development of the multi-stage central current-limiting air supply grille enables hot air to flow in an air supply pipeline to reach a fully developed state, increases the cost performance and improves the drying efficiency.

Disclosure of Invention

The invention aims to increase the air outlet uniformity of the outlet of the gradually expanding section of the air path, reduce the phenomena of vortex and the like, improve the drying efficiency and the drying quality of the air path, and simultaneously has the advantages of simple structure as much as possible, small occupied space, easily obtained raw materials and low manufacturing cost.

In order to achieve the purpose, the invention adopts the following technical scheme:

a multi-stage center flow-limiting air supply grille. The grid is formed by arranging hollow stainless steel pipes according to a certain rule, the hollow stainless steel pipes are arranged in the central area of the gradually expanding section at equal intervals, the areas on two sides are arranged at equal intervals at large intervals, and the multi-stage grid is arranged along the air supply channel, so that the outlet air uniformity of the gradually expanding section is remarkably improved, and the local vortex and backflow of air at the outlet of the gradually expanding section are reduced.

Preferably: the hollow pipes forming the grating are square, the hydraulic diameter of the hollow pipes is small in the middle of the area, the periphery of the hollow pipes is enlarged, and the range of small intervals of the steel pipes from the arrangement area is the width of an inlet of a gradually expanding section; the other two side areas are steel pipe large-interval arrangement areas. The length of the outer edge of the square hollow pipe forming the grid is 10% of the width of the inlet of the divergent section, the range of the small-interval arrangement area of the steel pipes is the width of the inlet of the divergent section, and the interval is 60% of the side length of the steel pipes; the other two side areas are steel pipe large-interval arrangement areas, and the interval is 80% of the side length of the steel pipes.

Preferably: the grating is placed at the middle position of the inlet and the outlet of the divergent section, and is placed at the outlet of the divergent section.

The invention has the beneficial effects that:

1) after the multi-stage central current-limiting air supply grille is additionally arranged, the uniformity of air outlet at the gradually expanding section is obviously improved.

2) Vortex and backflow phenomena at the downstream of the air outlet of the divergent section can be remarkably eliminated, and after the multi-stage central flow-limiting air supply grille is additionally arranged, vortex and backflow areas at the downstream of the air outlet of the divergent section are remarkably reduced.

3) In addition, the structure is simple, the raw materials are easy to obtain, the manufacturing cost is low, and the investment and production are facilitated.

Drawings

FIG. 1 is a schematic view showing the flow direction of an air passage of a multi-stage center flow-limiting type air-supplying grille

FIG. 2 is a schematic view of the installation position of a multi-stage center flow-limiting type air supply grille

FIG. 3 is a local flow field distribution diagram of a divergent section before a multi-stage central flow-limiting air supply grille is not arranged

FIG. 4 is a diagram of a divergent local flow field distribution diagram after a multi-stage central flow-limiting air supply grille is additionally arranged

Detailed Description

The present invention will be described in detail below with reference to the schematic structural diagram of the present invention. It should be noted that the described embodiments are only a part of the embodiments of the present invention, and do not represent all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The difference in uniformity of the flow of hot air in the ungrid and grilled channels can first be seen visually by comparing fig. 3 and 4. It can be seen that the uniformity of hot air flow in the divergent section is greatly improved after the grid is additionally arranged, and the area with vortexes is also obviously reduced. This clearly demonstrates the significant effect of the current limiting in the center of the invention.

A multi-stage central flow-limiting air supply grille is shown in figures 1 and 2 and is arranged at an air outlet connected with a hot air generating device and a divergent section of a drying chamber. The hot air flows out from the air outlet of the hot air generating device, flows through the gradually expanding section where the grating is located, and then uniformly flows into the drying chamber. The grating is formed by arranging hollow square stainless steel pipes according to a certain rule, the hollow square stainless steel pipes are equidistantly arranged in the central area of the gradually expanding section at small intervals, and the areas on the two sides are equidistantly arranged at large intervals.

In the embodiment, the length of the outer edge of the square hollow pipe forming the grid is about 10% of the width of the inlet of the divergent section, the range of the small spacing of the steel pipes from the arrangement area is the width of the inlet of the divergent section, and the spacing is about 60% of the side length of the steel pipes; the other two side areas are steel pipe large-interval arrangement areas, and the interval is about 80 percent of the side length of the steel pipe.

Further: the grating can be arranged in multiple stages, and after multiple computer simulations, a stage is arranged between the inlet and the outlet of the divergent section, and a stage is arranged at the outlet of the divergent section, so that a better uniform air supply effect can be achieved.

Under the conditions of the above embodiment, under the working conditions that the average wind speed of the cross section of the experimental inlet simulated by the computer is 0.5m/s, the inlet width is 1m, and the outlet width is 2m, after the central flow-limiting type air supply grille is additionally arranged, the maximum variance of the wind speed of the air outlet at the divergent section is reduced to 3% of the maximum variance of the wind speed of the air outlet at the divergent section without the grille.

In the description of the present invention, it should be noted that the terms "center", "exit", "entrance", "outside", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the referred device or component must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention; the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

The structure chart of the invention adopts a 2-layer stainless steel central flow-limiting type air supply grille, however, the specific size, the number of layers and the material of the grille need to be determined according to the aspects of the space in the field, the cost working condition and the like, and the grille has flexibility. It is within the scope of the present invention to provide such a multi-stage, center-flow-restricting air delivery grille.

Claims

1. A multi-stage central flow-limiting air supply grille is characterized in that: the hydraulic diameter of the hollow pipes is small in the middle and large on two sides, and the range of the small-interval arrangement area of the steel pipes is the width of an inlet of the divergent section; the other two side areas are steel pipe large-interval arrangement areas, the length of the outer edge of the square hollow pipe forming the grid is 10% of the width of the inlet of the divergent section, the range of the steel pipe small-interval arrangement areas is the width of the inlet of the divergent section, and the interval is 60% of the side length of the steel pipe; the other two side areas are steel pipe large-interval arrangement areas, and the interval is 80% of the side length of the steel pipes.

2. The multi-stage, center-flow-restricting air supply grille of claim 1, characterized in that: at least two layers of air supply grids are arranged in the central area of the gradually expanding section; the grilles are arranged along the air supply channel to form a central flow-limiting air supply channel with wide space at two sides and narrow middle.

3. The multi-stage, center-flow-restricting air supply grille of claim 1, characterized in that: the front part of the central area of the gradually expanding section is connected with an air outlet of a hot air generating device, and the rear part of the air channel is connected with an inlet of a drying chamber.

4. The multi-stage, center-flow-restricting air supply grille of claim 1, characterized in that: the hot air source has multiple forms, the electric air source heat pump, the boiler and the heat exchanger, the steam generated by the boiler heats the air at the other side, the air is electrically heated, and the air is heated by the combustion chamber.

5. The multi-stage, center-flow-restricting air supply grille of claim 1, characterized in that: the grating is placed at the middle position of the inlet and the outlet of the divergent section, and is placed at the outlet of the divergent section.