Water spraying experiment method for building surface

Abstract

The invention discloses a water spraying experiment method for a building surface, and belongs to the field of building fluid sealing performance detection. According to the water spraying simulation method, the maximum wind speed vw0 and the maximum rainfall R0 under the extreme weather are obtained, the rain load Pr is determined according to the maximum rainfall R0, the converted rain load Pt is obtained by determining the conversion coefficient beta and calculating, then the relational expression Ps = f (P, D) is fitted, and the waterproof capacity of the walls, the doors and the windows of the building under the condition that Ps = Pt is tested by adjusting the pressure P of a water pump. According to the method, the converted rain load Pt serves as an evaluation standard, the wall rain load Ps is adjusted by adjusting the pressure P of the water pump, control is convenient, the method is more reasonable, and the method can be applied to building waterproof performance inspection in all regions and has the advantage of being high in applicability.

Description

Technical Field

[0001] The invention relates to a water sprinkling test method for a building surface, and belongs to the field of building fluid tightness detection. Background Art

[0002] The water spray test is an experiment to check for leakage on the building's exterior walls, aluminum alloy doors and windows, curtain walls, etc. It is intended to detect leaks in the building's walls, doors and windows so that they can be modified and repaired to prevent water seepage in windy and rainy weather during use. The existing technical specifications mainly specify the parameters required for the water spray test equipment, but do not specify the actual pressure value on the wall surface during the water spray test, and do not directly reflect the effect of the water spray test. For example, the requirements for water sprinkling tests in the Technical Specifications for On-site Inspection of Building Waterproofing Projects JGJ / T299-2013 are as follows: the inner diameter of the water sprinkling pipeline should be (20±5) mm, the diameter of the water sprinkling holes on the pipeline should be 3 mm, the hole spacing should be 180 mm to 220 mm, the distance from the wall should not be greater than 150 mm, the water pressure should not be lower than 0.3 MPa, and a uniform water curtain should be formed on the surface of the area to be tested; the water sprinkling test should be carried out from top to bottom. To ensure the water pressure and flow rate, a water sprinkling pipeline should be added every 6 m to 10 m, and the continuous water sprinkling test time should not be less than 30 min.

[0003] Since the sprinkler specifications only specify the water pressure at the outlet, and the water pressure actually acting on the building wall after it is dissipated through the air is unknown, it is difficult for the construction party to determine whether the building leaks due to excessive pressure or due to substandard waterproofing measures. Summary of the invention

[0004] In view of the problems existing in the existing water sprinkling experiments, the present invention provides a water sprinkling test method for the surface of a building. By combining the climatic factors of the maximum wind speed and the maximum rainfall in the area, the actual rain load value on the surface of the building is used as the standard for the water sprinkling test, so that the water sprinkling test results have more reference value.

[0005] In order to solve the above technical problems, the present invention includes the following technical solutions:

[0006] A water spray test method for a building surface comprises the following steps:

[0007] Step 1: Collect historical meteorological data of the area where the building is located and obtain the maximum wind speed v w0 and the maximum rainfall R0;

[0008] Step 2: According to the maximum wind speed v w0 Determine the rain load P with the maximum rainfall R0 r ;

[0009] Step 3: Select the weather with wind speed and rainfall that meet the requirements to measure wind speed, rainfall and total wind and rain load to obtain the experimental rain load P. r ', according to P r '、P r The ratio of the two factors determines a reduction factor β, thereby determining the reduced rain load P t The calculation formula is: t =P r ×β;

[0010] Step 4: Based on the configured water pump and outlet type, establish the water pump pressure P, the distance from the outlet to the wall D, and the wall rain load P s The relationship between them satisfies: P s =f(P,D);

[0011] Step 5: In the water spray test, set the water spray equipment at a suitable location, measure the distance D from the water outlet to the wall, and adjust the water pump pressure P so that P s =P t , to test the building's anti-seepage ability.

[0012] further,

[0013] Furthermore, a laser rangefinder is provided on the sprinkler device to measure the distance D from the water outlet to the wall.

[0014] Furthermore, a plurality of pressure sensors are pre-arranged on the surface of the building to detect the spray water pressure on the surface of the building and synchronously feed back to the control terminal of the sprinkler equipment;

[0015] If the spray water pressure on the building surface is t If the deviation is within the preset range, the spraying will be normal. If the deviation exceeds the preset range, the control terminal will send a command to the water pump to adjust the water pump pressure P so that the spraying water pressure on the building surface is consistent with P t The deviation is within the preset range.

[0016] Further, in step 2, according to the maximum wind speed v w0 Determine the rain load P with the maximum rainfall R0 r , specifically including:

[0017] According to the maximum rainfall R0, determine the raindrop particle size distribution, including the raindrop particle size range and the proportion of each particle size; according to the raindrop particle size distribution, determine the vertical terminal velocity of raindrops of each particle size;

[0018] Use simulation software to establish a building grid model, input parameters: maximum wind speed v w0 , particle size value and corresponding proportion, vertical terminal velocity corresponding to each particle size, simulate the rain load P r .

[0019] Furthermore, the simulation model adopts a multiphase flow model, and the turbulence equation uses k-epsilon or k-omega.

[0020] Further, in step 2, according to the maximum wind speed v w0 Determine the rain load P with the maximum rainfall R0 r , specifically including:

[0021] According to the maximum rainfall R0, determine the raindrop size distribution, including the raindrop size range and the proportion of each size; according to the raindrop size distribution, determine the vertical terminal velocity of raindrops of each size; w0 As the horizontal velocity of raindrops, the terminal velocity of raindrops of each particle size is obtained according to the vertical terminal velocity of raindrops;

[0022] Calculation of extreme rain load P r ;

[0023]

[0024] In the formula, A is the area of ​​action, n is the number of raindrops, miv 0i is the momentum of the ith raindrop, and τ is the duration of the raindrop impact.

[0025] Furthermore, the raindrop spectrum is used to determine the raindrop size distribution.

[0026] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art: the water spraying test method for the building surface provided by the present invention obtains the maximum wind speed v under extreme weather conditions. w0 and the maximum rainfall R0, and determine the rain load P under extreme weather conditions r , by determining the reduction coefficient β and calculating the reduced rain load P t , and then fit the relationship P s =f(P,D), by adjusting the water pump pressure P, s =P t , to test the waterproof ability of building walls, doors and windows under this condition. t As the evaluation standard, the wall rain load P is adjusted by adjusting the water pump pressure P s , which is convenient to control and more reasonable, and this method can be applied to the inspection of building waterproof performance in all regions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The figure is a flow chart of a water spraying test method for a building surface in an embodiment of the present invention.

[0028] Figure 2Schematic diagram of the relationship among water pump pressure, distance from water outlet to wall, and rain load on wall in an embodiment of the present invention. DETAILED DESCRIPTION

[0029] The following is a further detailed description of the water spraying test method for building surfaces provided by the present invention in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer in conjunction with the following description. It should be noted that the accompanying drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0030] The main innovation of the water spraying test method for building surface provided by the present invention is that: by obtaining the maximum wind speed v under extreme weather conditions w0 The rain load in extreme weather is obtained by comparing it with the maximum rainfall R0. In the water spraying test, the pressure and flow are adjusted so that the pressure measured on the wall is equal to the rain load and the flow is equal to the maximum rainfall R0. This can test whether the walls, doors and windows of the building under such extreme conditions are leaking, making the water spraying test results more valuable for reference.

[0031] like Figure 1 As shown, the water spraying test method for building surface provided in this embodiment specifically includes the following steps:

[0032] Step 1: Collect historical meteorological data of the area where the building is located and obtain the maximum wind speed v w0 For a specific area, query the historical wind speed and rainfall data of the target area, and filter out the maximum wind speed v w0 (m / s), and the maximum rainfall R0 (mm / h) as the basis for calculation. For example, the maximum wind speed v in a coastal city w0 is 38.4m / s(1915) and the maximum rainfall R0 is 117.5mm / h(2008).

[0033] Step 2: According to the maximum wind speed v w0 Determine the rain load P with the maximum rainfall R0 r The rain load P can be determined using existing technology. r .

[0034] Step 3: Select the weather with wind speed and rainfall that meet the requirements to measure wind speed, rainfall and total wind and rain load to obtain the experimental rain load P. r ', according to P r '、P r The ratio of the two factors determines a reduction factor β, thereby determining the reduced rain load P t The calculation formula is: t =P r ×β. Through the maximum wind speed v w0The rain load P determined by the maximum rainfall R0 r The calculation is relatively conservative, so it can be adjusted by setting the conversion factor β to obtain the reduced rain load P t It should be pointed out that experimental measurements usually have high requirements for weather conditions. It is difficult to encounter extremely severe weather, and the combinations of wind speed and rainfall that appear are also relatively random. Therefore, when the numerical simulation results are in good agreement with the experiment, the rain load values ​​under different wind speed and rainfall combinations can be quickly obtained through numerical simulation, and representative values ​​of rain loads with regional characteristics can be established.

[0035] Step 4: Based on the configured water pump and outlet type, establish the water pump pressure P, the distance from the outlet to the wall D, and the wall rain load P s The relationship between them satisfies: P s =f(P,D). In actual projects, rain load is controlled by adjusting the water pump pressure. After the water pressure at the water outlet is dispersed by the air, the actual rain load acting on the wall is not consistent with the water outlet pressure of the water pump. Therefore, it is necessary to establish a mapping relationship between the water pump pressure, the distance from the water outlet to the wall, and the wall rain load.

[0036] Step 5: In the water spray test, set the water spray equipment at a suitable location, measure the distance D from the water outlet to the wall, and adjust the water pump pressure P so that P s =P t , to test the anti-seepage capacity of the building. The sprinkler equipment can be equipped with a laser rangefinder to measure the distance between the water outlet and the building surface (wall). At the same time, multiple pressure sensors are pre-arranged on the surface of the building, and the water pressure detected on them will be synchronously fed back to the sprinkler equipment. If the water pressure detected on the pressure sensor is consistent with the set rain load, the intelligent sprinkler equipment will operate normally. If not, the sprinkler equipment will further adjust the water pump pressure until the two match. For example: the extreme rain load P that a certain area should be subjected to r =20kpa, the distance from the water outlet to the wall D=50cm, and the calculated water pump pressure is about 0.6Mpa. After the sprinkler equipment adjusts the water pump pressure, it will perform pre-spraying. The pressure sensor pre-installed on the wall measures the actual wall water pressure to be 20kpa. After receiving the signal and confirming that the water pressure is correct, the sprinkler equipment will continue to spray to evaluate the building's anti-seepage ability.

[0037] In a specific embodiment, based on the water pump and outlet type at the construction site, the relationship between the distance from the outlet to the wall, the water pump pressure and the rain load value can be measured through experiments. For example, for a common water pump and outlet type, the relationship between the three is measured, such as Figure 2 As shown. Figure 2It can be seen that compared with the water pump pressure, the distance from the water outlet to the wall has a greater impact on the wall rain load. As the distance from the water outlet to the wall increases, the wall rain load decreases rapidly. Based on the experimental results, a theoretical formula between the three can be established.

[0038]

[0039] In a specific embodiment, in step 2, according to the maximum wind speed v w0 Determine the rain load P with the maximum rainfall R0 r , specifically including:

[0040] According to the maximum rainfall R0, determine the raindrop particle size distribution, including the raindrop particle size range and the proportion of each particle size; a rainfall event will contain raindrops of many particle sizes, and the size and distribution of raindrop particle diameters directly affect the rain load value on the building surface; using the raindrop spectrum, such as the Λ distribution, the raindrop particle size distribution under the corresponding rainfall can be obtained. For example: when the rainfall is 100mm / h, the raindrop particle size range is 0-6mm, of which the particle size within the diameter of 1.5-4mm accounts for more than 70%, and the particle size of 2.5mm accounts for the largest proportion, reaching 10%; the rainfall is 117.5mm / h, and the main particle size range is 2-5mm, with an interval of 0.5mm, accounting for 5%, 7.5%, 10%, 15%, 10%, 7.5% and 5% of the total particle size respectively;

[0041] The vertical terminal velocity of raindrops of different particle sizes is determined according to the distribution of raindrop particle sizes. The terminal velocity of raindrops is divided into two parts: horizontal terminal velocity and vertical terminal velocity. In the horizontal direction, since the rain phase itself has no velocity, it is driven by the wind to fall on the wall, and its horizontal terminal velocity is the same as the wind speed that drives it to drop obliquely. In the vertical direction, the buoyancy of the raindrop itself will balance the acceleration of gravity, and it will fall at a uniform speed. Therefore, the terminal velocity of the raindrop is:

[0042]

[0043] Where: is the raindrop terminal velocity, is the wind speed, is the vertical terminal velocity of the raindrop; It is only related to the raindrop particle size. For example, in the Matzler calculation formula, when the raindrop diameter is 6mm, the vertical terminal velocity of the raindrop is is 9.37m / s; when the raindrop diameter is 5mm, the vertical terminal velocity of the raindrop is 8m / s, combined with the horizontal wind speed of 38.4m / s, it can be calculated that the terminal velocity of the 5mm particle size raindrop is 42m / s; therefore, the vertical terminal velocity of the raindrop can be determined according to the raindrop diameter, and the terminal velocity of the raindrop can be obtained by combining the wind speed;

[0044] Calculation of extreme rain load P r ;

[0045]

[0046] In the formula, A is the area of ​​action, n is the number of raindrops, miv 0i is the momentum of the ith raindrop, and τ is the duration of the raindrop impact. w0 When the maximum rainfall R0 is 117.5 mm / h, P is calculated. r =22.21kpa.

[0047] In a specific embodiment, in step 2, according to the maximum wind speed v w0 Determine the rain load P with the maximum rainfall R0 r , specifically including:

[0048] According to the maximum rainfall R0, determine the raindrop particle size distribution, including the raindrop particle size range and the proportion of each particle size; according to the raindrop particle size distribution, determine the vertical terminal velocity of raindrops of each particle size;

[0049] Use simulation software to establish a building grid model, input parameters: maximum wind speed v w0 , particle size value and corresponding proportion, vertical terminal velocity corresponding to each particle size, simulate the rain load P r .

[0050] As an example, the simulation model uses a multiphase flow model, such as the Euler-Euler, VOF model, etc., and the turbulence equation uses a common equation, such as k-epsilon or k-omega. For example, the fluid simulation software fluent, in which the grid model of the entire building and the rainfall area are established; secondly, the wind speed and rainfall are input, and the wind speed is directly input in the form of a wind profile according to the maximum wind speed value (38.4m / s); the maximum rainfall (117.5mm / h) is realized by inputting different particle size types, proportions and corresponding vertical terminal velocities; the model uses a multiphase flow model, such as the Euler-Euler model and the k-epsilon equation; P is calculated r =23.55kpa.

[0051] It should be noted that the actual test results of the ultimate rain load P r When verifying and adjusting the value, choose relatively windy and rainy weather to measure wind speed (wind load), rainfall (rain load) and total wind and rain load. The wind-driven rain load is directly measured by a distributed pressure sensor. The wind load is measured under a rainless roof. The rain load is the wind-driven rain load minus the pure wind load. Compare the experimentally measured rain load with the calculated rain load, and adjust and correct the calculated extreme rain load. First, β is a value less than or equal to 1 and greater than 0, such as P r ' / P r=0.7, β is also greater than or equal to 0.7, such as β = 0.75, 0.78, 0.82, 0.85, 0.9 or 0.93. When selecting a specific value, it is necessary to consider the actual weather conditions of the test. It should be pointed out that the conversion coefficient β is not a fixed value for different regional characteristics, but is confirmed by a large number of experiments based on regional characteristics.

[0052] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0053] The above-mentioned embodiments only express several implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A water spray test method for a building surface, characterized in that: The steps include: Step 1: Collect historical meteorological data of the area where the building is located and obtain the maximum wind speed v w0 and the maximum rainfall R0; Step 2: According to the maximum wind speed v w0 Determine the rain load P with the maximum rainfall R0 r ; Step 3: Select the weather with wind speed and rainfall that meet the requirements to measure wind speed, rainfall and total wind and rain load to obtain the experimental rain load P. r ', according to P r '、P r The ratio of the two factors determines a reduction factor β, thereby determining the reduced rain load P t The calculation formula is: t =P r ×β; Step 4: Based on the configured water pump and outlet type, establish the water pump pressure P, the distance from the outlet to the wall D, and the wall rain load P s The relationship between them satisfies: P s =f(P,D); Step 5: In the water spray test, set the water spray equipment at a suitable location, measure the distance D from the water outlet to the wall, and adjust the water pump pressure P so that P s =P t , to test the building's anti-seepage ability.

2. The water spray test method for building surface according to claim 1, characterized in that:

3. The water spray test method for building surface according to claim 1, characterized in that: The sprinkler equipment is equipped with a laser rangefinder to measure the distance D from the water outlet to the wall.

4. The water spray test method for building surface according to claim 1, characterized in that: A plurality of pressure sensors are pre-arranged on the surface of the building to detect the spray water pressure on the surface of the building and synchronously feed back to the control terminal of the sprinkler equipment; If the spray water pressure on the building surface is t If the deviation is within the preset range, the spraying will be normal. If the deviation exceeds the preset range, the control terminal will send a command to the water pump to adjust the water pump pressure P so that the spraying water pressure on the building surface is consistent with P t The deviation is within the preset range.

5. The water spray test method for building surface according to claim 1, characterized in that: In step 2, according to the maximum wind speed v w0 Determine the rain load P with the maximum rainfall R0 r , specifically including: According to the maximum rainfall R0, the raindrop particle size distribution is determined, including the raindrop particle size range and the proportion of each particle size; according to the raindrop particle size distribution, the vertical terminal velocity of raindrops of each particle size is determined; Use simulation software to establish a building grid model, input parameters: maximum wind speed v w0 , particle size value and corresponding proportion, vertical terminal velocity corresponding to each particle size, simulate the rain load P r .

6. The water spray test method for building surface as claimed in claim 5, characterized in that: The simulation model adopts the multiphase flow model, and the turbulence equation uses k-epsilon or k-omega.

7. The water spray test method for building surface according to claim 1, characterized in that: In step 2, according to the maximum wind speed v w0 Determine the rain load P with the maximum rainfall R0 r , specifically including: According to the maximum rainfall R0, determine the raindrop size distribution, including the raindrop size range and the proportion of each size; according to the raindrop size distribution, determine the vertical terminal velocity of raindrops of each size; w0 As the horizontal velocity of raindrops, the terminal velocity of raindrops of each particle size is obtained according to the vertical terminal velocity of raindrops; Calculation of extreme rain load P r ; In the formula, A is the effective area, n is the number of raindrops, m is the i v 0i is the momentum of the ith raindrop, and τ is the duration of the raindrop impact.

8. The water spray test method for building surface according to any one of claims 5 to 7, characterized in that: The raindrop spectrum is used to determine the raindrop size distribution.

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