Testing apparatus for fluid resistance performance of flat plate surface

Abstract

The invention discloses a testing apparatus for a fluid resistance performance of a flat plate surface. The testing apparatus is characterized in that a water tank, a frequency conversion pump, a settling chamber, a diffusion section, a contraction section, a working section and a spreading section are communicated successively to form a water circulation system. A test box is arranged above the working section and a lower opening is communicated with an upper pipe wall of the working section; and a bottom of a horizontal testing flat plate suspended inside the test box is flush with the inner wall of the upper pipe wall of the working section to form a constituent part of a flowing channel and the part is located above the flow of the working section. A pressure contact of a pressure sensor is in movable contact with a suspension rod of the testing flat plate along a horizontal direction; and the pressure sensor and a programmable logic controller arranged outside the test box are connected electrically. Therefore, a drag reduction effect of the flat plate surface after texturing or reducing material coating can be measured accurately; the stable flow is obtained based on the precise structure design of the water circulation system; and the interference like friction between the frame of the pipe wall and the flow is eliminated by suspending the testing flat plate. Moreover, the testing method is simple and is easy to operate; and the testing is accurate.

Description

technical field [0001] The invention relates to a testing device, in particular to a testing device for testing the drag-reducing effect of a flat surface textured or coated with a drag-reducing paint in different flow rates of water. Background technique [0002] The resistance of the hull surface is mainly divided into frictional resistance and pressure difference resistance, and frictional resistance is the most important component. At present, the research on ship drag reduction technology mainly focuses on reducing frictional resistance, which is very important for improving energy efficiency, It is of great significance to reduce greenhouse gas emissions and improve the environment. Texturing the surface of the hull or applying drag-reducing coatings are effective drag-reducing technologies, and it is particularly important to design a test device that can quickly and accurately evaluate the drag-reducing effect of the material surface after being textured or coated wi...

AI Technical Summary

Problems solved by technology

Most of the traditional water tunnel or tank test devices have problems such as high cost, high cost, large volume, and difficult control of experimental conditions.

[0003] It can be seen through document retrieval that some existing small hydrodynamic measuring devices related to the present invention have the following types: the first is a rotary resistance testing device, such as the patent publication number is CN103471806A, and the name is "a rotary drum type Fluid friction resistance tester" and the patent publication number are CN103512844A, and the name is "non-smooth surface fluid friction resistance test device and non-smooth surface drag reduction effect evaluation method", all of which convert the water flow velocity into rotational motion, but the test plate is not a circle The shape will produce pressure difference resistance, which will affect the test results; the second is a drag-type resistance measuring device, such as the patent publication number is CN102288382A, the name is "a kind of drag-type fluid resistance test device" and the patent publication number is CN103743541A, The title is "Experimental Device and Method for Evaluating the Effect of Bionic Non-smooth Surface Drag Reduction", all of which replace the flow of fluid by dragging a flat plate to form relative motion, which is not intuitive enough; the third is the flow channel resistance measurement device, For example, the patent publication number is CN102023130B, and the name is "a flow channel type marine organism adhesion test device". Result accuracy is not high enough; There is also a kind of simplified plate resistance measuring device, such as the patent publication number is CN104634538, and the name is called "a kind of experimental device for measuring flat plate flow resistance", the structure is relatively simple, and the stability of turbulent flow and the stability of turbulent flow are not fully considered. The friction problem between the support and the test piece affects the measurement accuracy

[0004] On the other hand, in the aforementioned testing device, the sample is placed in the lower part of the flow channel and fixed, and then the pressure difference between the water flow passing through the sample and after the water flow is measured, but the pipe wall in this section will also be in contact with the water flow. Friction is generated, and the friction generated by the pipe wall cannot be eliminated, which will cause distortion of the measurement results

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