Tester for the effect of sediment on high-speed water flow cavitation

Abstract

The test instrument for the influence of sediment on high-speed water flow cavitation includes a base, a cooling water pool is arranged on the base, a water storage pool is arranged in the cooling water pool, and a sand-containing water sample is arranged in the water storage pool; the water storage pool is connected to a circulation pipeline, and the circulation pipeline includes a main pipeline, a first branch pipe, a secondary pipeline, a second branch pipe and a third branch pipe, and the main pipeline is provided with a first water pump, a second water pump and a cavitation section for generating cavitation in sequence along the water flow direction, and a concrete test piece is arranged in the cavitation section; the outlet end of the main pipeline is connected to the first branch pipe and the secondary pipeline through a tee, the outlet end of the secondary pipeline is connected to the second branch pipe and the third branch pipe through a tee, and the outlet ends of the first branch pipe, the second branch pipe and the third branch pipe are all connected to the water storage pool through a valve. The present invention studies the abrasion of concrete test pieces by cavitation water flow under the influence of sediment by observing the degree of destruction of the concrete test pieces, is easy to operate, and can study the influence of sand content, particle size, etc. on high-speed water flow cavitation.

Description

Technical Field

[0001] The invention relates to the technical field of hydraulic cavitation testing, in particular to a test on the influence of sediment on high-speed water flow cavitation. Background Art

[0002] The flow velocity of water in spillway, spillway and other water discharge structures is relatively high. According to Bernoulli's equation, the water pressure will decrease as the flow velocity increases. When the flow velocity reaches a certain level, that is, the water pressure is lower than the corresponding saturated steam pressure, cavitation will occur. Cavitation will lead to unstable flow, violent vibration and noise, reduce its hydraulic performance, and cavitation will occur when the water flows from the low-pressure area to the higher-pressure area. The shock wave and micro-jet formed by the collapse of the cavitation bubble will cause cavitation damage on the material surface, reducing its service life.

[0003] Unlike general clean water projects, there is sediment in natural rivers, and there is a sediment effect in sand-laden water flow. As a special solid-liquid two-phase flow medium, when the sediment concentration or sediment particle size changes, the motion characteristics and physical and chemical characteristics of the sand-laden water flow will also change accordingly. After cavitation occurs, the flow changes to solid-liquid-gas three-phase flow, which will inevitably cause the change of the internal motion structure of the mixed fluid, thereby having a specific impact on the cavitation of high-speed water flow. As for whether the influence of sediment "promotes" cavitation or "inhibits" cavitation? How much does the sediment content affect cavitation? It is extremely complicated to explore these issues only from a theoretical perspective. At present, there is a lack of a physical model experimental method to study the comprehensive characteristics of the influence of sediment in sand-laden water flow on cavitation. Summary of the invention

[0004] In order to overcome the above problems, the present invention provides a simple-to-operate tester for testing the effect of sediment on high-speed water flow cavitation.

[0005] The technical solution adopted by the present invention is: a test instrument for the influence of sediment on high-speed water flow cavitation, comprising a base, a cooling water pool is arranged on the base, a water storage pool is arranged in the cooling water pool, and a water sample containing sand is arranged in the water storage pool; the water storage pool is connected to a circulation pipeline, and the water inlet and the water outlet of the circulation pipeline are both connected to the water storage pool;

[0006] The circulation pipeline includes a main pipeline, a first branch pipeline, a secondary pipeline, a second branch pipeline and a third branch pipeline. The water inlet end of the main pipeline is connected to the water storage tank. The main pipeline is provided with a first water pump, a second water pump and a cavitation section for generating cavitation in sequence along the water flow direction. The cross section of the cavitation section is a square section, and the cross-sectional area of ​​the cavitation section is smaller than that of the main pipeline. The two side walls of the cavitation section are provided with transparent observation windows for easy observation. The bottom of the cavitation section is provided with a movable bottom plate, and a plurality of pressure measuring holes arranged in sequence are provided on the movable bottom plate. Pressure sensors for collecting water flow pressure data during the test are installed in the pressure measuring holes. The top of the cavitation section is provided with an installation groove for placing a concrete specimen, and the bottom of the installation groove is connected with the interior of the cavitation section, so that the lower part of the concrete specimen can extend into the interior of the cavitation section. A top cover is installed on the top of the installation groove, and the top cover is sealed with the installation groove.

[0007] The water outlet end of the main pipeline is connected to the first branch pipe and the secondary pipeline through a tee, and the water outlet end of the secondary pipeline is connected to the second branch pipe and the third branch pipe through a tee; the water outlet ends of the first branch pipe, the second branch pipe and the third branch pipe are all connected to the water storage tank, and the first branch pipe, the second branch pipe and the third branch pipe are respectively provided with a first valve, a second valve and a third valve; the secondary pipeline and the third branch are respectively provided with a first electromagnetic flowmeter and a second electromagnetic flowmeter.

[0008] Furthermore, the water storage tank is also connected to a first drainage pipeline for discharging waste water, and a first drainage valve is provided on the first drainage pipeline.

[0009] Furthermore, the cooling water pool is connected to a second drainage pipeline for discharging cooling water, and a second drainage valve is provided on the second drainage pipeline.

[0010] Furthermore, a high-speed camera for observing cavitation growth is provided outside the observation window.

[0011] Furthermore, the observation window is a plexiglass observation tube.

[0012] Furthermore, the cross section of the concrete specimen is in an inverted "convex" shape, and the shape of the mounting groove is adapted to the shape of the concrete specimen.

[0013] The beneficial effects of the present invention are: by observing the degree of destruction of concrete specimens, the abrasion of concrete specimens by cavitation water flow under the influence of sediment is studied; the operation is simple and convenient; and the influence of sand content, particle size, etc. on high-speed water flow cavitation can be studied. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a plan view of the present invention.

[0015] Figure 2 It is a side view of the cavitation section.

[0016] Figure 3 It is a cross-sectional view of the cavitation section.

[0017] Figure 4 It is a structural diagram of the concrete specimen.

[0018] Explanation of the accompanying drawings: 1. Cooling water tank; 2. Water storage tank; 3. First water pump; 4. Second water pump; 5. Cavitation section; 51. Mounting groove; 52. Observation window; 53. Pressure measuring hole; 6. First valve; 7. Second valve; 8. Third valve; 9. First electromagnetic flowmeter; 10. Second electromagnetic flowmeter; 11. Second drain valve; 12. First drain valve. DETAILED DESCRIPTION

[0019] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0021] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] Referring to the attached drawings, a tester for the effect of sediment on high-speed water flow cavitation includes a base, a cooling water pool 1 is provided on the base, a water storage pool 2 is provided in the cooling water pool 1, a water sample containing sediment of a certain concentration is added to the water storage pool 2, the water containing sediment sample quantitatively mixes water and sediment, and the sediment content does not change during the test, so that the effect of sediment on high-speed water flow cavitation can be studied; the water storage pool 2 is connected to a circulation pipeline, and the water inlet and outlet of the circulation pipeline are both connected to the water storage pool 2;

[0023] The circulation pipeline includes a main pipeline, a first branch pipeline, a secondary pipeline, a second branch pipeline and a third branch pipeline. The water inlet end of the main pipeline is connected to a water storage tank 2. The main pipeline is provided with a first water pump 3 and a second water pump 4 for circulating the water sample in the entire test instrument, and a cavitation section 5 for generating cavitation in sequence along the water flow direction. The cross section of the cavitation section 5 is a square section, and the cross-sectional area of ​​the cavitation section 5 is smaller than that of the main pipeline. The two side walls of the cavitation section 5 are provided with observation windows 52 made of organic glass for easy observation, and a high-speed camera for observing the growth of cavitation bubbles is provided on the outer side of the observation window 52. The bottom of the cavitation section 5 A movable bottom plate is provided, on which a plurality of pressure measuring holes 53 arranged in sequence are provided, and a pressure sensor for collecting water flow pressure data during the test is installed in the pressure measuring hole 53; a mounting groove 51 is provided on the top of the cavitation section 5, in which concrete specimens of different strengths in the shape of an inverted "convex" are embedded, and the bottom of the mounting groove 51 is connected with the interior of the cavitation section, so that the lower part of the concrete specimen can extend into the interior of the cavitation section; a top cover is connected to the top of the mounting groove 51 by bolts, and the top cover is sealed with the mounting groove 51; by observing the degree of damage to the concrete specimen, the abrasion of the concrete specimen by the cavitation water flow under the influence of sediment is studied.

[0024] The outlet of the main pipeline is connected to the first branch and the secondary pipeline through a tee, and the outlet of the secondary pipeline is connected to the second branch and the third branch through a tee; the outlets of the first branch, the second branch and the third branch are all connected to the water storage tank 2, and the first valve 6, the second valve 7 and the third valve 8 are respectively provided on the first branch, the second branch and the third branch; the first electromagnetic flowmeter 9 and the second electromagnetic flowmeter 10 are respectively provided on the secondary pipeline and the third branch. The flow rate of the cavitation section 5 is adjusted by the first valve 6, the second valve 7 and the third valve 8 in cooperation with the first electromagnetic flowmeter 9 and the second electromagnetic flowmeter 10.

[0025] The water storage tank 2 is also connected to a first drainage pipeline for discharging waste water, and a first drainage valve 12 is provided on the first drainage pipeline; the cooling water tank 1 is connected to a second drainage pipeline for discharging cooling water, and a second drainage valve 11 is provided on the second drainage pipeline.

[0026] The contents described in the embodiments of this specification are merely an enumeration of the implementation forms of the inventive concept. The protection scope of the present invention should not be regarded as limited to the specific forms described in the embodiments. The protection scope of the present invention also extends to equivalent technical means that can be conceived by those skilled in the art based on the inventive concept.

Claims

1. The test instrument for the effect of sediment on high-speed water flow cavitation is characterized by: The base comprises a cooling water pool, a water storage pool is provided in the cooling water pool, and a water sample containing sand is provided in the water storage pool; the water storage pool is connected to a circulation pipeline, and the water inlet and outlet of the circulation pipeline are both connected to the water storage pool; The circulation pipeline includes a main pipeline, a first branch pipeline, a secondary pipeline, a second branch pipeline and a third branch pipeline. The water inlet end of the main pipeline is connected to the water storage tank. The main pipeline is provided with a first water pump, a second water pump and a cavitation section for generating cavitation in sequence along the water flow direction. The cross section of the cavitation section is a square section, and the cross-sectional area of ​​the cavitation section is smaller than that of the main pipeline. The two side walls of the cavitation section are provided with transparent observation windows for easy observation. The bottom of the cavitation section is provided with a movable bottom plate, and a plurality of pressure measuring holes arranged in sequence are provided on the movable bottom plate. Pressure sensors for collecting water flow pressure data during the test are installed in the pressure measuring holes. The top of the cavitation section is provided with an installation groove for placing a concrete specimen, and the bottom of the installation groove is connected with the interior of the cavitation section, so that the lower part of the concrete specimen can extend into the interior of the cavitation section. A top cover is installed on the top of the installation groove, and the top cover is sealed with the installation groove. The water outlet of the main pipeline is connected to the first branch pipe and the secondary pipeline through a tee, and the water outlet of the secondary pipeline is connected to the second branch pipe and the third branch pipe through a tee; the water outlets of the first branch pipe, the second branch pipe and the third branch pipe are all connected to the water storage tank, and the first branch pipe, the second branch pipe and the third branch pipe are respectively provided with a first valve, a second valve and a third valve; the secondary pipeline and the third branch are respectively provided with a first electromagnetic flowmeter and a second electromagnetic flowmeter; The water storage tank is also connected to a first drainage pipeline for discharging waste water, and a first drainage valve is provided on the first drainage pipeline; The cooling water pool is connected to a second drainage pipeline for discharging cooling water, and a second drainage valve is provided on the second drainage pipeline; The cross section of the concrete test piece is in an inverted "convex" shape, and the shape of the installation groove is adapted to the shape of the concrete test piece.

2. The tester for the effect of sediment on high-speed water flow cavitation as claimed in claim 1, characterized in that: A high-speed camera for observing the growth of cavitation bubbles is arranged outside the observation window.

3. The tester for the effect of sediment on high-speed water flow cavitation as claimed in claim 1, characterized in that: The observation window is a plexiglass observation tube.

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