CN104282203A - Bernoulli equation demonstration instrument - Google Patents

Abstract

The invention belongs to the technical field of teaching and demonstration experiment equipment, and in particular relates to a demonstration instrument for Bernoulli equation. The Bernoulli equation demonstration instrument provided by the present invention is made up of ideal fluid demonstration area, viscous fluid demonstration area, and constitutes the front and back of demonstration instrument; Ideal fluid demonstration area comprises A scale plate, A guide tube, A demonstration tube, Four parts of the liquid tank; the viscous fluid demonstration area includes four parts of the B scale plate, funnel, B demonstration tube, and B guide tube; in the ideal fluid demonstration area, by passing the high-speed air flow in the guide tube, observe Demonstrate the height of the liquid level in the tube to demonstrate the Bernoulli equation of the ideal fluid; in the viscous fluid demonstration area, demonstrate the Bernoulli equation of the viscous fluid by demonstrating the difference in the outflow velocity of the viscous fluid in the tube. The invention is small in size, convenient to carry, simple in operation and good in stability, and is suitable for being carried to classrooms for demonstrations.

Description

A Bernoulli Equation Demonstration Instrument

technical field

The invention belongs to the technical field of teaching and demonstration experiment equipment, in particular to a demonstration instrument capable of simultaneously demonstrating the Bernoulli equation of ideal fluid and the Bernoulli equation of viscous fluid.

Background technique

Bernoulli's equation is one of the most basic equations in fluid mechanics and has a large number of applications in engineering design. At the same time, the Bernoulli equation has different manifestations in ideal fluid and viscous fluid. Its essence reflects the energy conservation relationship inside the fluid. A thorough understanding of this equation is very important for students to learn fluid mechanics.

Because the fluid is a continuous medium, the energy relationship in it is difficult to show, so students have great difficulties in the process of understanding and mastering this basic theory. It is urgent to have a good demonstration instrument to explain the theory. This instrument is exactly This blank has been filled and good classroom teaching effect has been received.

Contents of the invention

The purpose of the present invention is to provide a device which is small in size, easy to carry, simple in operation and good in stability, and can respectively demonstrate the Bernoulli equation under the conditions of ideal fluid and viscous fluid in the classroom.

The Bernoulli equation demonstration instrument provided by the present invention has a structure as shown in Figures 1, 2, and 3, and is composed of an ideal fluid demonstration area 1 and a viscous fluid demonstration area 2, and constitutes the front and back sides of the demonstration instrument; wherein:

The ideal fluid demonstration area 1 (as shown in FIG. 2 , is the front side), includes four parts: A scale plate 3 , A guide tube 4 , A demonstration tube 5 , and a liquid tank 6 . Wherein, the liquid tank 6 is located below the entire demonstration area 1; the A scale plate 3 is located at the rear of the demonstration area; the material of the A scale plate 3 is not limited, as long as it is rigid; The tubes are sealed and connected to each other, placed horizontally, and fixed on the A scale plate; the A demonstration tube 5 is composed of a group of vertically placed transparent tubes with the same diameter, and the upper end of each tube is respectively connected to a section of A with a different diameter. The guide tube is sealed and communicated, and the lower end is open, and is placed in the liquid tank 6 . During the demonstration, first inject the dyed liquid into the liquid tank, blow air with an air pump at one end of the guide tube, and observe the rising height of the liquid in each demonstration tube. the

The viscous fluid demonstration area 2 (as shown in FIG. 3 , the reverse side) includes four parts: B scale plate 7 , funnel 8 , B demonstration tube 9 , and B draft tube 10 . Wherein, the B scale plate 7 is on the other side of the A scale plate 3, that is, the B scale plate 7 and the A scale plate 3 share the two sides of one plate; There is a switch; the B demonstration tube 9 is also composed of a group of transparent tubes placed vertically at equal intervals with the same pipe diameter. The upper end of each B demonstration tube is open, and the lower end communicates with the B draft tube 10. Each tube of the B demonstration tube 9 is fixed on the B scale plate 7 respectively; During the demonstration, first close the switch of the guide tube, slowly inject the dyed viscous fluid from the funnel until each demonstration tube is almost full, then turn on the switch, and observe the characteristics of the viscous fluid when it flows out.

In the present invention, all components are made of rigid transparent materials.

In the present invention, the reciprocal (1/d) of the inner diameters of each section of the A draft tube (4) is in an equidifferential relationship.

There are scale lines on the A scale plate 3 and B scale plate 7, or the scale paper is pasted to help the observer observe the demonstration effect more clearly.

In the present invention, the Bernoulli equation of ideal fluid is demonstrated by the method of rising height of dyed liquid level; the Bernoulli equation of viscous fluid is demonstrated by the method of descending velocity of dyed viscous fluid.

The demonstration instrument of the invention is small in volume, convenient to carry, simple in operation and good in stability, and can respectively demonstrate the Bernoulli equation under the conditions of ideal fluid and viscous fluid in the classroom.

Description of drawings

Figure 1 is a side view of the demo instrument.

Figure 2 is the front of the demonstration instrument, which is a schematic diagram of the ideal fluid demonstration area.

Figure 3 is the reverse side of the demonstration instrument, which is a schematic diagram of the device in the viscous fluid demonstration area.

Numbers in the figure: 1 is ideal fluid demonstration area, 2 is viscous fluid demonstration area, 3 is A scale plate, 4 is A guide tube, 5 is A demonstration tube, 6 is liquid tank, 7 is B scale plate, 8 Is the funnel, 9 is the B demonstration tube, and 10 is the B diversion tube.

Detailed ways

The Bernoulli equation demonstration instrument provided by the present invention is composed of an ideal fluid demonstration area 1 and a viscous fluid demonstration area 2, the structures of which are shown in Figures 1, 2 and 3. in:

The ideal fluid demonstration area 1 (as shown in FIG. 2 ) includes four parts: a scale plate A 3 , a guide tube A 4 , a demonstration tube A 5 , and a liquid tank 6 . The role of the scale plate is to fix the diversion tube on the one hand, and to help observe the phenomenon on the other hand. The size is based on the principle of convenient observation and easy handling. The thickness is not limited, and rigidity is enough. Therefore, the plexiglass plate is used in this device. The base of the scale plate, the size is 60cm*50cm, and the printed scale paper is pasted on the surface; each section of the A diversion tube must be rigid and the length is the same, take about 10cm, this device uses a plexiglass tube, and each section guides The reciprocal of the inner diameter of the tube (1/d) is in an equidifferential relationship, and the tubes of each section are sealed and connected to each other, and placed horizontally; the demonstration tube A is composed of a group of identical vertically placed transparent and rigid tubes, and the diameter is not limited. The device also uses plexiglass tubes. The upper end of each tube is sealed and communicated with a section of diversion tube with different diameters, and the lower end is open and placed in the liquid tank; the liquid tank can be made of transparent plexiglass, with a size of 60cm*6cm*8cm .

During the demonstration, first inject the dyed liquid (such as red ink) into the liquid tank, blow air with an air pump at one end of the guide tube, and observe the rising height of the liquid in each demonstration tube.

The viscous fluid demonstration area 2 (as shown in FIG. 3 ) includes four parts: the B scale plate 7 , the funnel 8 , the B demonstration tube 9 , and the B draft tube 10 . B scale plate 7 and A scale plate 3 share both sides of a plate; the size and material of the funnel are not limited, and the lower end is connected with the one on the edge of the B demonstration tube; It is composed of rigid transparent tubes with unlimited diameters. This device also uses plexiglass tubes. The upper end of each B demonstration tube is open, and the lower end communicates with a B diversion tube with uniform thickness. The connection is sealed with the outside world. It is fixed on the B scale plate; the B guide tube is placed horizontally and should be made of rigid and transparent materials. This device uses a plexiglass tube, and a switch is installed at the end of the guide tube.

When demonstrating, first close the switch of the guide tube, slowly inject the dyed viscous fluid (such as glycerin mixed with red ink) from the funnel until each demonstration tube is almost full, then turn on the switch, and observe when the viscous fluid flows out. specialty.

Claims (6)

1. A Bernoulli equation demonstrator, which is used to respectively demonstrate the Bernoulli equation under ideal fluid and viscous fluid conditions, and is characterized in that it is composed of an ideal fluid demonstration area and a viscous fluid demonstration area, and constitutes the front of the demonstrator and the opposite; where: The ideal fluid demonstration area includes four parts: A scale plate, A guide tube, A demonstration tube, and liquid tank; wherein, the liquid tank is located below the entire demonstration area; there are scale lines on the A scale plate; The tube is composed of several sections of tubes with different diameters. The tubes are sealed and connected to each other. They are placed horizontally and fixed on the A scale plate; The upper ends of the root canals are sealed and communicated with a section of A diversion tubes with different diameters, and the lower ends are open and placed in the liquid tank; The viscous fluid demonstration area includes four parts: B scale plate, funnel, B demonstration tube, and B diversion tube; wherein, the B scale plate is on the other side of the A scale plate, that is, the B scale plate is shared with the A scale plate One plate; the B diversion tube is uniform in thickness, placed horizontally, located in the lower part of the demonstration area, and a switch is installed at the end; the B demonstration tube is composed of a group of transparent tubes with the same diameter and equidistant vertical placement, and the upper end of each B demonstration tube is open , the lower end communicates with the B guide tube, and the connection is sealed with the outside world. The tubes of the B demonstration tube are respectively fixed on the B scale plate; the funnel is connected with the one on the side of the B demonstration tube. 2. Bernoulli equation demonstrator as claimed in claim 1, is characterized in that all parts all adopt rigid transparent material. 3. The Bernoulli equation demonstrator as claimed in claim 1, is characterized in that the reciprocals of the internal diameters of each section of the A draft tube form an equal difference relationship. 4. Bernoulli's equation demonstrator as claimed in claim 1, is characterized in that the ideal fluid Bernoulli's equation is demonstrated with the method of dyeing liquid level rising height. 5. The Bernoulli equation demonstrating instrument as claimed in claim 1, is characterized in that demonstrating the viscous fluid Bernoulli equation with the method of dyeing viscous fluid descending velocity. 6. The Bernoulli equation demonstrator as claimed in claim 1, characterized in that there are scale lines on the A scale plate and the B scale plate, or the scale paper is pasted to help the observer to observe the demonstration effect more clearly.