Demonstration box for relation between fluid pressure and flow velocity

Abstract

The utility model provides a fluid pressure and flow velocity relation demonstration box which comprises a demonstration box body, a second latex tube is arranged on the top of a second connecting tube, a plastic box is arranged on the side edge of the second connecting tube, and a glass tube is arranged on the side edge of a threaded hose. According to the fluid pressure and flow velocity relation demonstration box, through installation of a first plastic cup and a communicating pipe, colored water is poured into a middle communicating pipe, water in three middle thin pipes accounts for about 2 / 3, at the moment, the liquid levels of the three pipes are flush, a blower is turned on, and due to the thickness change of a glass container, the flow velocities of gas at the positions where the glass pipes are communicated with the three thin pipes are different, so that the relationship between the pressure and the flow velocity is demonstrated. The liquid levels of the three thin tubes are different in height, the middle communicated glass tube is thinnest, the left side is second than the right side, the rightmost side is thickest, stably flowing gas flows through a place with a large cross section, the flow speed is small, the pressure intensity is large, the flow speed is large, the pressure intensity is small, and the liquid levels of the liquid in the three thin tubes are highest in the middle, second than the left side and lowest in the rightmost side.

Description

Technical Field

[0001] The utility model relates to the technical field of physical teaching aids, in particular to a demonstration box for the relationship between fluid pressure and flow velocity. Background Art

[0002] In 1726, the Swiss scientist Daniel Bernoulli discovered the "boundary layer surface effect" through numerous experiments: when the fluid velocity increases, the pressure on the interface between the object and the fluid decreases, and vice versa. In memory of his discovery, this phenomenon is later called the "Bernoulli effect" by later generations. The Bernoulli effect applies to all fluids including gases, and is one of the basic phenomena when the fluid flows stably, reflecting the relationship between the pressure and flow velocity of the fluid.

[0003] The teaching content of Section 4, Chapter 9 of the eighth-grade physics textbook of the People's Education Edition is "the relationship between fluid pressure and flow velocity". Two experiments are designed in the textbook: "blowing coins" and "blowing paper pieces", to explore the relationship between fluid pressure and flow velocity through gas flow, and then it is simply stated that "more experimental results show the conclusion that 'in gases and liquids, the position with a greater flow velocity has a smaller pressure'". Since the concept of the Bernoulli effect is relatively abstract to understand, and the existing experiments in textbooks are relatively single and cannot leave students with an intuitive and profound impression, and the experimental teaching aids on the market that can intuitively display this law tend to have a complex structure and are inconvenient to operate. Therefore, a demonstration box for the relationship between fluid pressure and flow velocity is designed, which can display the above law through the simplest, most economical, cheapest, most intuitive and easiest-to-operate demonstration.

[0004] Currently, the existing demonstration boxes for the relationship between fluid pressure and flow velocity are inconvenient to operate and the phenomena are not very interesting during the demonstration. As a result, when used in classroom teaching, they cannot increase students' interest or enable students to actually participate in the experiment, and students cannot obtain an intuitive feeling, thus reducing the use effect of the demonstration box. Utility Model Content

[0005] In view of the above defects or deficiencies in the prior art, the present application aims to provide a demonstration box for the relationship between fluid pressure and flow velocity, including a demonstration box body, a box cover is provided on the top of the demonstration box body, a handle strap is provided on the top of the box cover, a first plastic cup is provided inside the demonstration box body, a first connecting pipe is provided at the bottom of the first plastic cup, a fixing ring is provided outside the first connecting pipe, a through pipe is provided on the side of the fixing ring, a first latex tube is provided at the top of the through pipe, a second connecting pipe is provided on the side of the through pipe, a second latex tube is provided at the top of the second connecting pipe, a plastic box is provided on the side of the second connecting pipe, a second plastic cup is provided at the rear of the demonstration box body, a threaded hose is provided on the top of the second plastic cup, and a glass tube is provided on the side of the threaded hose.

[0006] Preferably, the box cover is movably installed on the upper surface of the demonstration box body, and the handle strap is installed on the upper surface of the box cover.

[0007] Preferably, the first plastic cup is installed on the inner wall of the demonstration box body, the first connecting pipe is connected to the lower surface of the first plastic cup, and the fixing ring is installed on the outer wall of the first connecting pipe.

[0008] Preferably, the through pipe is connected to one side of the fixing ring, the first latex tube is connected to the upper surface of the through pipe, the second connecting pipe is connected to one side of the through pipe, the second latex tube is connected to the upper surface of the second connecting pipe, and the plastic box is installed on one side of the second connecting pipe.

[0009] Preferably, the second plastic cup is installed on the back of the demonstration box body, the threaded hose is connected to the upper surface of the second plastic cup, and the glass tube is connected to one side of the threaded hose. Beneficial effects

[0010] 1. When demonstrating the relationship between fluid pressure and flow rate, first find an unused paper box with appropriate size. According to the sizes of the plastic box for storing liquid and the second plastic cup filled with shredded paper, cut out corresponding holes on the front and back of the box with a utility knife to facilitate the placement of the containers. Then spray the whole box with milky white paint, pay attention to even spraying. After the paint dries, fix the glass container to the demonstration box body with white plastic zip ties. Insert the threaded hose into the left glass tube of the gas pressure demonstration teaching aid. Cut a small hole with a length of 1 cm and a width of 0.1 cm in the middle of the side cover with a utility knife. The small holes are about 10 cm apart. Pass the carrying handle through the small holes from top to bottom and fix it with hot melt adhesive. The carrying handle is made. Fix 4 strong magnets to both sides of the side cover and one side of the demonstration box body that coincides with the side cover with hot melt adhesive in turn. Pay attention to the direction of the magnets to ensure that the box lid can be well attracted together when closed. In this way, the demonstration box body for the relationship between fluid pressure and flow rate is completed. The teaching aid needs to be used in cooperation with a household hair dryer during use, and the effect is obvious.

[0011] 2. The demonstration box for the relationship between fluid pressure and flow velocity is installed with a first plastic cup and a connecting pipe. The middle connecting pipe is filled with colored water. The water in the three middle thin pipes accounts for about 2 / 3. At this time, the liquid levels in the three pipes are flat. When the hair dryer is turned on, due to the change in the thickness of the glass container, the gas flow velocities at the positions where the connecting pipe connects the three thin pipes are different. Therefore, the liquid levels in the three pipes show different heights. The middle connected glass pipe is the thinnest, the left one is the second thinnest, and the rightmost one is the thickest. The gas flowing steadily has a small flow velocity and a large pressure when flowing through a large cross-section area, while when flowing through a small cross-section area, the flow velocity is large and the pressure is small. So, the liquid level in the middle thin pipe is the highest, the left one is the second highest, and the rightmost one is the lowest. At the same time, turn the left end of the plastic transparent threaded hose in the opposite direction and place it into the first plastic cup. The hair dryer air outlet is close to the right glass pipe opening. Turn on the switch and blow air upward. Since the gas flow velocity at the glass pipe opening increases and the air pressure decreases, and because white shredded paper is placed in the first plastic cup, the white shredded paper is pressed by the atmospheric pressure through the threaded hose to the right opening of the glass pipe. Thus, there are the effects of "dust suction" and "flower scattering". Or by turning the left end of the plastic transparent threaded hose upward and blowing air horizontally with the hair dryer air outlet close to the right glass pipe opening, and placing a foam ball at the threaded hose opening, it can be observed that the foam ball suspends in the air. Move the threaded hose, and the foam ball moves with it.

[0012] 3. For this demonstration box of the relationship between fluid pressure and flow velocity, first clamp the second latex tube with a stopcock, then pour water with red pigment into the first plastic cup. The liquid level height is approximately 2 / 3 of the entire first plastic cup. At this time, the liquid levels in the first plastic cup, the first latex tube, and the plastic box are flush. Open the stopcock and observe the descending speed of the liquid levels in the two thin latex tubes. Since the fluid in stable flow has a lower flow velocity and higher pressure when flowing through a place with a larger cross-section, and a higher flow velocity and lower pressure when flowing through a place with a smaller cross-section, the descending speed of the liquid level in the rightmost first plastic cup is faster than that in the middle first latex tube. At the same time, the demonstration box body of the teaching aid can be placed laterally, take out two table tennis balls and place them at the top of the side. The table tennis balls are about 2 cm apart. Blow air towards the two table tennis balls with a straw and observe the movement trend of the table tennis balls. It can be found that the table tennis balls will move closer to the middle. Or insert the paper with a straw fixed on one side into the wire bracket in turn. The distance between the two papers is about 7 cm. Place the wire bracket at the side cover of the box and fix it with a strong magnet. Turn on the hair dryer and observe the phenomenon. The two papers will move closer to each other. You can also take out the foam airplane model. Make hollow tracks on both the front and back sides of the airplane model with straws. The distance between the tracks is about 7 cm. Insert the two feet of the wire bracket into the tracks in turn so that the wing model can slide freely up and down along the wire bracket. Place the wire bracket at the side cover of the box and fix it with a strong magnet. Turn on the hair dryer and blow air towards the airplane model and observe the movement of the airplane model. This makes the demonstration box body can be directly used for classroom teaching, solving technical problems such as inconvenient operation and lack of interesting phenomena. And in actual teaching, students can participate in the operation by themselves, judge the relationship between fluid pressure and flow velocity through the observed experimental phenomena, and thus draw conclusions. Since students can actually participate in the experiment and obtain an intuitive feeling, students have a deep understanding of the fact that the pressure is low where the flow velocity is high and the pressure is high where the flow velocity is low. At the same time, this demonstration box is made of existing materials, with low cost and simple operation. The relationship between fluid pressure and flow velocity is demonstrated obviously, and students are easy to understand, which is beneficial to the development, popularization and promotion of experiments and teaching. It also uses the idea of the combination method, integrating different fluid pressure experiments into one device in an integrated form, reducing the time for teachers to prepare equipment, and teachers can better invest in teaching preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Other features, objects, and advantages of the present application will become more apparent by reading the detailed description of the non-limiting embodiments with reference to the following drawings:

[0014] Figure 1 It is a front three-dimensional structural schematic diagram of the demonstration box of the relationship between fluid pressure and flow velocity of the present utility model;

[0015] Figure 2 It is a rear three-dimensional structural schematic diagram of the demonstration box of the relationship between fluid pressure and flow velocity of the present utility model;

[0016] Figure 3This is the upper view three-dimensional structure schematic diagram of the demonstration box for the relationship between fluid pressure and flow rate of the present utility model;

[0017] Figure 4 This is the upper view structure schematic diagram of the demonstration box for the relationship between fluid pressure and flow rate of the present utility model.

[0018] In the figure: 1. Demonstration box body; 101. Box cover; 102. Handle strap; 2. First plastic cup; 201. Glass tube; 3. First connecting pipe; 4. Fixed ring; 5. Communicating pipe; 6. First latex tube; 7. Second connecting pipe; 8. Second latex tube; 9. Plastic box; 10. Second plastic cup; 11. Threaded hose. Specific embodiments

[0019] The following further details the present application with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only for explaining the relevant utility model and not for limiting the utility model. Additionally, it should be noted that for ease of description, only the parts related to the utility model are shown in the drawings.

[0020] In the drawings of the embodiments of the present utility model: The different types of hatching in the figure are not marked according to the national standard, nor are the materials of the components required. It is to distinguish the cross-sectional views of the components in the figure.

[0021] Please refer to Figures 1-4 , a demonstration box for the relationship between fluid pressure and flow rate, comprising a demonstration box body 1, a box cover 101 is provided on the top of the demonstration box body 1, a handle strap 102 is provided on the top of the box cover 101, a first plastic cup 2 is provided inside the demonstration box body 1, a first connecting pipe 3 is provided at the bottom of the first plastic cup 2, a fixed ring 4 is provided outside the first connecting pipe 3, a communicating pipe 5 is provided on the side of the fixed ring 4, a first latex tube 6 is provided on the top of the communicating pipe 5, a second connecting pipe 7 is provided on the side of the communicating pipe 5, a second latex tube 8 is provided on the top of the second connecting pipe 7, a plastic box 9 is provided on the side of the second connecting pipe 7, a second plastic cup 10 is provided at the rear of the demonstration box body 1, a threaded hose 11 is provided on the top of the second plastic cup 10, and a glass tube 201 is provided on the side of the threaded hose 11.

[0022] Among them, the box cover 101 is movably installed on the upper surface of the demonstration box body 1, and the handle strap 102 is installed on the upper surface of the box cover 101.

[0023] Among them, the first plastic cup 2 is installed on the inner wall of the demonstration box body 1, the first connecting pipe 3 is connected to the lower surface of the first plastic cup 2, and the fixed ring 4 is installed on the outer wall of the first connecting pipe 3.

[0024] Among them, the communicating pipe 5 is connected to one side of the fixed ring 4, the first latex tube 6 is connected to the upper surface of the communicating pipe 5, the second connecting pipe 7 is connected to one side of the communicating pipe 5, the second latex tube 8 is connected to the upper surface of the second connecting pipe 7, and the plastic box 9 is installed on one side of the second connecting pipe 7.

[0025] Among them, the second plastic cup 10 is installed on the back of the demonstration box body 1, the threaded hose 11 is connected to the upper surface of the second plastic cup 10, and the glass tube 201 is connected to one side of the threaded hose 11.

[0026] When conducting a demonstration, first find an unused cardboard box. The size of the box just needs to be appropriate. According to the sizes of the plastic box for storing liquid and the second plastic cup 10 filled with shredded paper, cut out corresponding holes on the front and back of the box with a utility knife in turn to facilitate the insertion of the containers. Then spray the whole box white with milky white spray paint, paying attention to even spraying. After waiting for the spray paint to dry, fix the glass container to the demonstration box body 1 with white plastic cable ties. Insert the threaded hose 11 into the left glass tube 201 of the gas pressure demonstration teaching aid. Use a utility knife to cut a small hole with a length of 1 cm and a width of 0.1 cm in the middle of the side cover. The small holes are about 10 cm apart. Pass the carrying strap 102 through the small holes from top to bottom and fix it with hot melt glue. The carrying strap 102 is completed. Fix 4 strong magnets to both sides of the side cover and one side of the demonstration box body 1 that coincides with the side cover with hot melt glue in turn. Pay attention to the direction of the magnets to ensure that the lid 101 can be well attracted together when the box is closed. In this way, the demonstration box body 1 for the relationship between fluid pressure and flow rate is completed. The teaching aid needs to be used in cooperation with a household hair dryer during use, and the effect is obvious. Through the installation of the first plastic cup 2 and the connecting pipe 5, pour colored water into the middle connecting pipe 5. The water in the three middle thin pipes accounts for about 2 / 3. At this time, the liquid levels of the three pipes are flat. Turn on the hair dryer. Due to the change in the thickness of the glass container, the gas flow rates at the positions where the connecting pipe 5 connects the three thin pipes are different. Therefore, the liquid levels of the three pipes show different heights. The middle connecting glass tube is the thinnest, the left one is the second, and the rightmost one is the thickest. The gas flowing steadily has a small flow rate and a large pressure when passing through a large cross-section area, while when passing through a small cross-section area, the flow rate is large and the pressure is small. Therefore, the liquid level in the middle of the three thin pipes is the highest, the left one is the second, and the rightmost one is the lowest. At the same time, turn the left end of the plastic transparent threaded hose 11 in a different direction and place it into the first plastic cup 2. Place the hair dryer nozzle close to the right glass tube 201 opening and turn on the switch to blow air upward. Since the gas flow rate at the right glass tube 201 opening is accelerated and the air pressure becomes smaller, and because white shredded paper is placed in the first plastic cup 2, the white shredded paper is pressed to the right opening of the glass tube 201 through the threaded hose 11 under the action of the atmospheric pressure. Thus, the effects of "dust suction" and "flower scattering" are achieved. Or turn the left end of the plastic transparent threaded hose 11 upward, place the hair dryer nozzle close to the right glass tube 201 and blow air horizontally. Place the foam ball at the threaded hose 11 opening, and it can be observed that the foam ball suspends in the air. Move the threaded hose 11, and the foam ball moves accordingly. First, clamp the second latex tube 8 with a stopcock clip, and then pour water with red pigment into the first plastic cup 2. The liquid level height is about 2 / 3 of the whole first plastic cup 2. At this time, the liquid levels of the first plastic cup 2, the first latex tube 6, and the plastic box 9 are flat. Open the stopcock clip and observe the descending speed of the liquid levels in the two thin latex tubes. Since the steadily flowing fluid has a small flow rate and a large pressure when passing through a large cross-section area, while when passing through a small cross-section area, the flow rate is large and the pressure is small, the descending speed of the liquid level in the rightmost first plastic cup 2 is faster than that in the middle first latex tube 6.Meanwhile, the teaching aid demonstration box body 1 can be placed laterally. Take out two table tennis balls and place them at the top of the side. The table tennis balls are about 2 cm apart. Blow air towards the two table tennis balls with a straw and observe the movement trend of the table tennis balls. It can be found that the table tennis balls will move closer to the middle. Or insert the papers with straws fixed on one side into the wire brackets in turn. The distance between the two papers is about 7 cm. Place the wire brackets at the side cover of the box and fix them with a strong magnet. Turn on the hair dryer and observe the phenomenon. The two papers will move closer to each other. You can also take out the foam aircraft model. Make hollow tracks on both the front and back sides of the aircraft model with straws. The distance between the tracks is about 7 cm. Insert the two feet of the wire bracket into the tracks in turn so that the wing model can slide freely up and down along the wire bracket. Place the wire brackets at the side cover of the box and fix them with a strong magnet. Turn on the hair dryer and blow air towards the aircraft model and observe the movement of the aircraft model. This makes the demonstration box body 1 can be directly used in classroom teaching, solves technical problems such as inconvenient operation and lack of interesting phenomena, and in actual teaching, students can participate in the operation by themselves and judge the relationship between fluid pressure and flow velocity through the observed experimental phenomena, so as to draw conclusions. Since students can actually participate in the experiment and obtain an intuitive feeling, they have a deep understanding of the principle that the pressure is small where the flow velocity is large and the pressure is large where the flow velocity is small. At the same time, the demonstration box is made of existing materials, with low cost and simple operation. The relationship between fluid pressure and flow velocity is demonstrated obviously and students are easy to understand, which is beneficial to the development, popularization and promotion of experiments and teaching. It also uses the idea of the combination method, integrating different fluid pressure experiments into one device in an integrated form, reducing the time for teachers to prepare equipment, and teachers can better devote themselves to teaching preparation.,

[0027] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0028] The above description is only the preferred embodiment of the present application and the explanation of the applied technical principle. Those skilled in the art should understand that the scope of the utility model involved in the present application is not limited to the technical solution formed by the specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept of the utility model. For example, the technical solutions formed by mutually replacing the above features with the (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A demonstration box for demonstrating the relationship between fluid pressure and flow velocity, comprising a demonstration box body (1), characterized in that: The demonstration box body (1) is provided with a box cover (101) at the top, and a hand strap (102) is provided at the top of the box cover (101). A first plastic cup (2) is provided inside the demonstration box body (1), and a first connecting tube (3) is provided at the bottom of the first plastic cup (2). A fixing ring (4) is provided outside the first connecting tube (3). A through tube (5) is provided on the side of the fixing ring (4). A first latex tube (6) is provided on the top of the through tube (5). A second connecting tube (7) is provided on the side of the through tube (5). A second latex tube (8) is provided on the top of the second connecting tube (7). A plastic box (9) is provided on the side of the second connecting tube (7). A second plastic cup (10) is provided at the rear of the demonstration box body (1). A threaded hose (11) is provided on the top of the second plastic cup (10), and a glass tube (201) is provided on the side of the threaded hose (11).

2. The fluid pressure and flow velocity relationship demonstration box according to claim 1, characterized in that: The box cover (101) is movably mounted on the upper surface of the demonstration box body (1), and the hand strap (102) is mounted on the upper surface of the box cover (101).

3. The fluid pressure and flow velocity relationship demonstration box according to claim 1, characterized in that: The first plastic cup (2) is mounted on the inner wall of the demonstration box body (1), the first connecting tube (3) is connected to the lower surface of the first plastic cup (2), and the fixing ring (4) is mounted on the outer wall of the first connecting tube (3).

4. The fluid pressure and flow velocity relationship demonstration box according to claim 1, characterized in that: The through pipe (5) is connected to one side of the fixing ring (4), the first latex tube (6) is connected to the upper surface of the through pipe (5), the second connecting pipe (7) is connected to one side of the through pipe (5), the second latex tube (8) is connected to the upper surface of the second connecting pipe (7), and the plastic box (9) is installed on one side of the second connecting pipe (7).

5. The fluid pressure and flow velocity relationship demonstration box according to claim 1, characterized in that: The second plastic cup (10) is mounted on the back of the demonstration box body (1), the threaded hose (11) is connected to the upper surface of the second plastic cup (10), and the glass tube (201) is connected to one side of the threaded hose (11).

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