CN106437988A - Underwater exhaust port structure preventing water backflow - Google Patents

Abstract

The invention provides an underwater exhaust port structure for preventing water backflow, which prevents water backflow of a power device below the water surface during exhaust in a ship using underwater exhaust, and is characterized in that it includes: a straight pipe part , arranged horizontally, one end of the straight pipe part communicates with the exhaust gas exhaust pipeline of the power plant; The beginning end communicates with the straight pipe portion, the end of the transition pipe portion is the exhaust port, the vertical height of the transition pipe portion gradually decreases from the beginning end to the end, and the transverse width of the transition pipe decreases from the The starting end increases gradually from the end, so the cross section at the end of the transition tube is flat.

Description

An underwater vent structure to prevent water backflow

technical field

The invention relates to an exhaust pipe, in particular to an anti-backflow underwater exhaust pipe opening structure, which belongs to the field of machinery.

Background technique

In power, chemical and nuclear energy and other occasions, there are many applications for gas-liquid two-phase reverse flow, such as underwater exhaust of diesel engines, standpipe condensers, cooling towers, falling film chemical reactors, gravity heat pipes, and nuclear reactor accidents During water injection. In the process of gas-liquid two-phase reverse flow, there are two extreme phenomena of great significance in engineering applications, namely backflow and submersion. These flow phenomena greatly affect industrial equipment. For example, in the nuclear power generation system, the gas-liquid reverse flow characteristics of the hot section of the loop are crucial to the safety analysis of the reactor loss of water accident; During start-up, shutdown and no-load operation, seawater may flow back into the diesel engine through the exhaust pipe, causing serious damage to the diesel engine. Reasonable selection of the opening pressure of the tongue valve on the exhaust pipe and the minimum non-backflow speed at no-load is the best Exhaust diesel engine prevents backflow of seawater, which is an important guarantee for safe and efficient work. Therefore, for the gas-liquid two-phase reverse flow similar to the underwater exhaust of a diesel engine, preventing submersion and reverse flow plays an important role in the safe operation of the equipment.

At present, the way to realize underwater exhaust can be through negative pressure zone exhaust or underwater power boost exhaust. The exhaust method to form a negative pressure area is to install a deflector at the exhaust port to form a vortex, thereby reducing the exhaust back pressure and realizing the underwater discharge of exhaust gas. However, the range and pressure of the negative pressure area are limited by the Due to the influence of speed, water depth, etc., the exhaust method in the negative pressure area is difficult to be universally applicable; the underwater power booster exhaust uses the high-pressure gas discharged from the air compressor to open up the passage for the exhaust of the diesel engine, overcomes the exhaust back pressure, and realizes underwater exhaust. However, due to the increase of the air compressor, the energy consumption and weight of the exhaust system also increase.

Contents of the invention

The present invention is proposed to solve the above problems, and the purpose is to provide an underwater exhaust port structure capable of preventing water backflow of the power unit when exhausting.

The present invention adopts following technical scheme:

The present invention provides an anti-backflow underwater exhaust port structure, which prevents water backflow of a power device below the water surface during exhaust in a ship using underwater exhaust, and is characterized in that it includes: a straight pipe part, Horizontally arranged, one end of the straight pipe part communicates with the exhaust gas exhaust pipeline of the power plant; The end of the transition tube is the exhaust port, the vertical height of the transition tube gradually decreases from the beginning to the end, and the transverse width of the transition tube increases from the From the beginning end to the end, the cross-section is flattened at the end of the transition tube.

The anti-backflow underwater exhaust pipe provided by the present invention may also have the following feature: wherein, the cross section of the exhaust port is oval or rectangular.

Invention function and effect

According to the anti-backflow underwater exhaust port structure of this embodiment, since the vertical height of the gradient pipe portion gradually decreases from the beginning to the end, the vertical height of the flow channel is reduced. According to the experimental research on the limit of underwater exhaust backflow , indicating that reducing the vertical height of the flow channel can greatly reduce the critical gas velocity for water backflow, so the structure of the underwater exhaust port ensures that the power plant does not have water backflow under the operating conditions of low speed and low displacement , greatly reducing the no-load speed required by the power plant to prevent water backflow, reducing the risk of accidents and improving the economic performance of the power plant operation; Compared with the original pipeline, the cross-sectional area of the gas port has a small change, so the loss of exhaust pressure and the increase of injection noise will not be caused at the exhaust port.

Description of drawings

Fig. 1 is the schematic diagram in actual use of the anti-backflow underwater vent in the embodiment of the present invention;

Fig. 2 is the three-dimensional structure schematic diagram of the anti-backflow underwater vent of the embodiment of the present invention;

Fig. 3 is a front view of the exhaust pipe of Fig. 2;

Fig. 4 is a right view of the exhaust pipe of Fig. 2; and

Fig. 5 is a three-dimensional structural schematic diagram of the anti-backflow underwater air vent of the present invention when it is rectangular.

detailed description

Example

The specific implementation manners of the embodiments of the present invention will be described below in conjunction with the accompanying drawings.

Fig. 1 is a schematic diagram of the actual use of the anti-backflow underwater vent in the embodiment of the present invention.

The underwater exhaust of the following ships is taken as an example.

As shown in Figure 1, the anti-backflow underwater exhaust pipe 100 of the ship 200 is arranged horizontally, and communicates with the exhaust gas exhaust pipeline 211 of the power plant 210 of the ship 200, and the anti-backflow underwater exhaust pipe 100 is included in the same The straight pipe portion 10 and the transition pipe portion 20 are arranged on the horizontal axis. The ship 200 travels on the water 300 , and the underwater exhaust pipe 100 is located in the water 300 .

Fig. 2 is the three-dimensional structure schematic diagram of the anti-backflow underwater exhaust pipe of the embodiment of the present invention;

Fig. 3 is a front view of the exhaust pipe of Fig. 2;

Fig. 4 is a right view of the exhaust pipe in Fig. 2 .

The dotted line X in the figure is the transverse direction of the cross section of the exhaust pipe 100 , and the dotted line Y is the longitudinal direction of the cross section.

As shown in FIG. 1 , FIG. 2 , FIG. 3 and FIG. 4 , the cross section of the underwater exhaust pipe 100 is circular, and includes a straight pipe portion 10 and a transition pipe portion 20 .

The straight pipe portion 10 has a circular cross section and is arranged horizontally, and one end thereof communicates with the exhaust pipeline 211 of the power plant.

The transition tube part 20 has an elliptical cross section, is horizontally arranged, and has a transition tube 21 and an exhaust port 22 .

The transition tube 21 has a start end 211 and an end 212 . The starting end 211 communicates with the other end of the straight pipe portion 10 . The vertical height of the transition tube 21 gradually decreases from the beginning 211 to the end 212 , while the transverse width gradually increases from the start 211 to the end 212 , and the corresponding cross-sectional area of the transition tube 21 gradually decreases from the beginning to the end.

The exhaust port 22 is disposed on the end 212 , the maximum length in the transverse direction is greater than the maximum length in the longitudinal direction, and the maximum length in the transverse direction is greater than the pipe diameter of the straight pipe portion 10 . In this embodiment, the cross-section of the exhaust port 22 is elliptical. Of course, the horizontal axis is the long axis, and the vertical axis is the short axis.

Underwater exhaust process:

The exhaust process of the anti-backflow underwater exhaust pipe 100 of this embodiment will be described in detail below.

First, the gas discharged from the power unit 210 passes through the exhaust gas exhaust pipeline 211, and after passing through the straight pipe part 10, the gas flow rate is stabilized to a certain extent;

Then, the gas passes through the transition tube 21, and the flow channel height in the transition tube 21 gradually decreases, and the flow channel height reaches the minimum when reaching the exhaust port 22;

Finally, the gas is exhausted from the exhaust port 22 .

Function and effect of embodiment

According to the anti-backflow underwater exhaust port of this embodiment, since the vertical height of the gradient pipe part gradually decreases from the beginning to the end, the vertical height of the flow channel is reduced. According to the experimental research on the limit of the underwater exhaust backflow, It shows that reducing the vertical height of the flow channel can greatly reduce the critical gas velocity at which water backflow occurs. Therefore, the structure of the exhaust port ensures that the power plant does not have water backflow under the operating conditions of low speed and low displacement, and greatly reduces Reduce the no-load speed required by the power unit to prevent water backflow, reduce the risk of accidents and improve the economic performance of the power unit operation; Compared with the original pipe, the cross-sectional area of the pipe has little change, so it will not bring exhaust pressure loss and injection noise increase at the exhaust port.

The cross section of the underwater exhaust pipe of this embodiment is circular, as the underwater exhaust pipe of the present invention, the cross section can also be rectangular, as shown in Figure 5, the underwater exhaust port 300 is rectangular, including The shape of the rectangular straight pipe portion 310 and the rectangular transition pipe portion 320 and the corresponding exhaust port 322 are also rectangular.

Although the specific implementations of the description of the present invention have been described above, so that those skilled in the art can understand the present invention, it should be clear that the present invention is not limited to the scope of the specific implementations. For those of ordinary skill in the art, as long as Various changes are within the spirit and scope of the present invention defined and determined by the appended claims, and these changes are obvious, and all inventions and creations utilizing the concept of the present invention are all included in the protection list.

Claims (2)

1. An underwater air vent structure for preventing water backflow, which prevents water backflow when the power plant below the water surface is located in a ship that adopts underwater exhaust, and is characterized in that it includes: a straight pipe part, arranged horizontally, one end of the straight pipe part communicates with the exhaust gas exhaust pipeline of the power plant; and Gradient pipe section, set horizontally, Wherein, the transition pipe part has a start end and an end, the start end of the transition pipe part communicates with the straight pipe part, and the end of the transition pipe part is the exhaust port, The vertical height of the transition pipe portion gradually decreases from the start end to the end end, and the maximum lateral width of the transition pipe portion gradually increases from the start end to the end end, The lateral width of the exhaust port is larger than its vertical height and is flat. 2. The underwater exhaust pipe for preventing water backflow as claimed in claim 1, characterized in that: Wherein, the cross section of the exhaust port is oval or rectangular.