CN101963171B - A T-type shunting and rectifying tee with a rectangular section - Google Patents

Abstract

The invention discloses a T-shaped splitting/rectifying tee, which comprises an inlet section and two outlet sections, wherein one outlet sections and the inlet section are on a same horizontal plane, and the plane on which the extension line of the other outlet section is arranged is perpendicular to the plane on which the inlet section is arranged, thereby forming a T-shaped structure; the inlet section is communicated with one outlet section through a horizontal connection end of a splitting section, the longitudinal connection end of the splitting section is communicated with a buffering section, and the lower end of the buffering section is provided with a rectifying section which is communicated with the other outlet section; rectifying vanes are arranged in the upper part of the rectifying section, and each rectifying vane is provided with a guide vane which divides the inner portion of the rectifying section into five fluid channel with equal flow. The T-shaped splitting/rectifying tee of the invention eliminates the speed layering formed after fluid flows through the T-shaped tee, thereby finally achieving the purpose of rectifying the fluid after the liquid flows through the T-shaped tee.

Description

A T-type shunting and rectifying tee with a rectangular section

technical field

The invention relates to a partial component in a ventilation and air-conditioning system, in particular to a T-shaped shunting and rectifying tee with a rectangular section.

Background technique

T-shaped tee is a very common pipe fitting that changes the flow direction of fluid and divides it in HVAC power fluid machinery. In the diversion pipeline, due to the turning of the fluid, there is a centrifugal force from the center of curvature to the outer arc of the pipe, which makes the fluid When transitioning from a straight section of pipe to a curved section (before the end of the bend), the pressure on the outer arc increases and the pressure on the inner arc decreases. Therefore, the flow velocity of the fluid at the outer dome will decrease, while the flow velocity of the fluid at the inner dome will correspondingly increase. Therefore, the diffusion effect appears near the outer arc surface, while the contraction effect appears near the inner arc surface. When the fluid transitions from the curved pipe section to the straight pipe section (after turning), the opposite phenomenon occurs, that is, the diffusion effect occurs near the inner arc surface, and the contraction effect occurs near the outer arc surface. The diffusion effect makes the fluid detach from the wall, and at the same time, the movement of the fluid in the curved pipe section to the outer arc surface due to inertia further aggravates the separation from the inner arc surface.

Due to the above reasons, after the fluid flows through the T-shaped tee and is split, the fluid will be stratified due to the effect of diffusion and contraction, as shown in Figure 1, which will cause the flow velocity of the fluid on the right side of the figure to be greater than that on the left side. This means that the fluid flow rate is not uniform. In the field of HVAC, on the one hand, vibrations will occur inside the pipes to generate noise; on the other hand, if this part of the fluid is directly sent into the room, it will cause the indoor air distribution to go against the design and affect indoor comfort.

Contents of the invention

The purpose of the present invention is to provide a T-type diverter and rectifier tee. The unique design of the T-type diverter and rectifier tee eliminates the velocity stratification formed after the fluid passes through the T-type tee, so as to finally achieve After the fluid is rectified.

In order to realize above-mentioned technical task, the present invention adopts following technical scheme to realize:

A T-shaped shunting and rectifying tee with a rectangular section, including an inlet section and two outlet sections, one of which is on the same level as the inlet section, and the plane where the extension line of the other outlet section is located is perpendicular to the plane where the inlet section is located, forming a T Font structure, the inlet section is connected to an outlet section through the horizontal connection end of the diversion section, the longitudinal connection end of the diversion section is connected to the buffer section, and a rectification section connected to another outlet section is provided at the downstream end of the buffer section; the rectification section The upstream end of the section is provided with rectifying vanes, and each rectifying vane is provided with guide vanes to divide the rectifying section into five equal-flow fluid passages.

Other technical characteristics of the present invention are:

The length of the buffer section is the same as the width of the inlet section pipeline.

The rectifying vane is in the form of an acute triangle along the longitudinal direction of the rectifying section, and has a certain inclination angle with the incoming flow direction, so that five fluid passages with different inlet sizes are formed in the rectifying section.

The guide vane has an acute-angled triangle with its back facing the direction of incoming flow, and is parallel to the longitudinal direction of the straightening section.

In addition, a method for determining the size of the inlets of the five fluid passages formed between each rectifying vane and the longitudinal direction of the rectifying section in the above-mentioned rectangular section T-shaped diverging and rectifying tee rectifying section is designed, which is characterized in that the method includes the following steps:

Step 1. Determine the state of the fluid flow field in the rectangular cross-section T-shaped diverter tee, run the Reynolds stress model and combine the SIMPLE algorithm according to the size of the two outlet pipes and the fluid velocity at the inlet of the pipe, and then simulate the T-shaped diverter before setting the rectification section The velocity field in the three-way pipe, so as to obtain the velocity distribution value of the fluid at the position of the rectification section;

Step 2, determine the entrance size of the five fluid passages formed between each rectifying vane and the longitudinal direction of the rectifying section of the T-shaped splitting and rectifying tee with rectangular section, according to the velocity distribution value of the fluid at the rectifying section position obtained in step 1, use the area Based on the principle of separation, the sizes of the inlets of the five fluid channels are obtained when the same condition of the fluid flow in each fluid channel is satisfied.

It can be seen from the above that the present invention first divides the fluid through the diversion section, so that the fluid enters the buffer section before the outlet, and the fluid is buffered in the buffer section to form a relatively stable fluid characteristic, and then passes through the rectification blade and the rectification section. Five fluid channels of different sizes formed between them cut the fluid at equal flow rates, and the lateral velocity of the fluid is eliminated by forming five channels of equal sizes between the guide vanes and the casing. In this way, the velocity stratification formed after the fluid passes through the T-shaped tee is eliminated, and the purpose of rectifying the fluid passing through the T-shaped tee is finally achieved, as shown in Figure 2.

Description of drawings

Fig. 1 is a flow velocity contour map when fluid passes through a traditional T-shaped tee;

Fig. 2 is the flow velocity contour diagram when fluid passes through the T-type tee behind the T-type shunting and rectifying tee of the present invention;

Fig. 3 is a structural representation of the present invention;

Fig. 4 is the integral diagram of fluid velocity distribution in the cross-section of the traditional T-shaped tee outlet section;

Fig. 5 is the velocity distribution diagram of the outlet section of the T-type shunting and rectifying tee in the embodiment of the present invention

Each symbol in the figure represents the following information: 1. Inlet section; 2. Diverter section; 3. Straightening vane; 4. Guide vane; outlet section; 11, rectification section; others, the direction of the arrow indicates the direction of fluid flow.

The specific content of the present invention will be described in further detail below in conjunction with the accompanying drawings.

Detailed ways

As shown in Figure 3, the rectangular section T-shaped shunting and rectifying tee includes an inlet section 1 and two outlet sections (5, 10), wherein one outlet section 10 is on the same level as the inlet section 1, and the other outlet section 5 The plane where the extension line is located is perpendicular to the plane where the inlet section 1 is located, forming a T-shaped structure. The inlet section 1 is connected to an outlet section 10 through the horizontal connection end of the diversion section 2, and the longitudinal connection end of the diversion section 2 is connected to the buffer section 9. Here The buffer section 3 is designed to ensure that a fluid with relatively stable fluid characteristics is formed in the entire confluent tee pipe. The rectification section 11 that links to each other with another outlet section 5 is provided at the buffer section 9 downstream ends; The upstream end in the described rectification section 11 is provided with rectification vanes (3, 6, 7, 8), each rectification vane has The guide vane 4 divides the rectifying section 11 into five equal-flow fluid passages, so as to achieve equal-flow cutting of the fluid in the entire diversion tee pipe.

Since the flow characteristics of the fluid become unstable after changing directions, in order to make it possible to form a relatively stable fluid characteristic, the flow of the fluid is equalized through five fluid channels of different sizes formed between the rectifying blade and the rectifying section. For cutting, the present invention sets a buffer section with the same length as the inlet section pipeline width before the rectification section.

In order to avoid the problem of increased resistance caused by the cutting fluid, and to cut the fluid more effectively, the rectifying blades (3, 6, 7, 8) form an acute triangle along the longitudinal direction of the rectifying section (11), and The incoming flow direction has a certain inclination angle, so that five fluid passages with different inlet sizes are formed in the rectifying section (11). When this type of guide vane collides with the fluid, the contact surface area is smaller, so the resulting collision resistance is also small, and the possibility of fluid vortex due to the collision is also small. In this way, the resistance caused by the cutting fluid can be effectively reduced.

Also in order to avoid the problem of increased resistance caused by the cutting fluid, and to more effectively guide the fluid flowing through the rectifying vanes, the guide vanes 4 are facing away from the direction of the incoming flow, forming an acute triangle, and longitudinally intersecting with the rectifying section 11. Parallel, when the fluid passes through the diversion section 2, the velocity component perpendicular to the incoming flow direction will be eliminated by the guide vane 4, thereby eliminating the possibility of the fluid passing through the diversion section 2 to form a vortex and increase resistance.

When the fluid flows through the T-shaped tee with a rectangular cross-section, due to the expansion and contraction effects mentioned above, a velocity layer with a high velocity on the right and a small velocity on the left will be formed at the position shown in Figure 1. The present invention uses the Reynolds stress model and the fluid flow velocity distribution and size after flowing through the T-shaped tee obtained by the SIMPLE algorithm to determine the distance between the rectifying blade and the shell, so that the fluid flows through the rectifying blade in each channel The fluid flow is the same. Since the fluid is cut by the rectifying vanes, the fluid will form a vortex after being cut. The rectifying sheet in the present invention offsets the lateral velocity of the fluid under the condition that the size of the cross section remains unchanged, so as to eliminate the vortex formed by it and make the fluid only have the longitudinal velocity. Thereby eliminating speed stratification and achieving the purpose of rectification.

The present invention designs a method for determining the size of the inlets of the five fluid channels formed between each rectifying vane (3, 6, 7, 8) in the rectifying section 11 of the above-mentioned rectangular cross-section T-shaped shunting and rectifying tee and the longitudinal direction of the rectifying section 11. Including the following steps:

Step 1. Determine the state of the fluid flow field in the T-shaped diverter tee, and run the Reynolds stress model combined with the SIMPLE algorithm according to the pipe sizes of the two outlet sections (5, 10) and the fluid velocity of the pipeline inlet section 1.

First, solve the momentum equation:

${\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}}_{\mathrm{<span\; class="notranslate">\; j</span>}}\frac{<span\; class="notranslate">\; \&PartialD;</span>{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{<span\; class="notranslate">\; \&PartialD;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}\frac{<span\; class="notranslate">\; \&PartialD;</span>\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; p</span>}}}{<span\; class="notranslate">\; \&PartialD;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; \&mu;</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}}{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}\frac{{<span\; class="notranslate">\; \&PartialD;</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{<span\; class="notranslate">\; \&PartialD;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; \&PartialD;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}}<span\; class="notranslate">\; -</span>\frac{<span\; class="notranslate">\; \&PartialD;</span>}{<span\; class="notranslate">\; \&PartialD;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; ij</span>}}$

Then solve the pressure-corrected continuity equation:

$\frac{<span\; class="notranslate">\; \&PartialD;</span>{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{<span\; class="notranslate">\; \&PartialD;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}$

ρ is fluid density; u _i , u _j are velocities, i, j are tensor subscripts, i, j=1, 2, 3; μ, μ _t are dynamic viscosities, subscript t indicates that the physical quantity is caused by turbulent fluctuations ; σ _k , σ _τ are constants; C _μ , C ₁ , C ₂ are empirical coefficients, and their values are shown in the table below.

And update the pressure and the mass flow rate of instant noodles to solve the Reynolds stress equation. And judge whether it is converged, if it converges, stop the calculation, if not, continue to solve the momentum equation. RSM model constants, as shown in Table 1:

Table 1. Model Constants

Coefficient C _μ C ₁ C ₂ σ _{k σε} value 0.09 1.44 1.92 1.0 1.3

Then simulate the velocity field in the T-shaped diverting and rectifying tee pipe before setting the rectifying section 11, so as to obtain the velocity distribution of the fluid at the position of the rectifying section 11.

Step 2, determine the inlet size of the five fluid passages formed between each rectifying vane (3, 6, 7, 8) of the T-type shunting and rectifying tee and the longitudinal direction of the rectifying section 11, according to the position of the rectifying section 11 obtained in step 1 The velocity distribution of the fluid is shown in Figure 4. Find the velocity of each point in the cross-section of the position of the rectification section 11, integrate the flow velocity and the distance between the fluid and the inner wall of the rectification section 11 from left to right, stop integrating when the flow rate meets 1/5 of the total flow rate, and obtain The distance is the setting distance between the rectifying blades and the inner wall of the rectifying section 11 and the setting distance between the rectifying blades. In this way, it is satisfied that the fluid flows in the five fluid channels are all connected and are all 1/5 of the total flow. The principle of area integration is used to complete the setting of the sizes of the inlets of the five fluid channels when the fluid flow rate in each fluid channel is the same.

Specific examples:

Specific embodiments of the present invention are provided below, and it should be noted that the present invention is not limited to the following specific embodiments, and all equivalent transformations done on the basis of the technical solutions of the present application all fall within the scope of protection of the present invention.

Following the above technical scheme, taking the optimization process of the T-shaped diverter tee for central air-conditioning duct connection as an example, first confirm the dimensions of each part of the T-shaped diverter and rectifier tee pipe, in which the size of the inlet section is 300mm×300mm, and the size of the two outlet sections Both are 300mm×300mm, the diverging section has a curvature of 1.5, the length of the rectifying section is 300mm, the length of the rectifying vanes in the rectifying section is 100mm, and the length of the guide vanes is 300mm.

Then list the discrete format of the momentum equation and the continuity equation, and use the simple method to solve it, and the velocity distribution value of the fluid at the position of the rectification section 11 can be obtained when no rectification section is added. Determine the size of the entrance of the rectification section, as shown in Figure 4. According to the integral principle, the area surrounded by the curve in Figure 4 is the flow rate. Taking the wind speed at the entrance as 7m/s as an example, the total flow rate at the entrance is 7m /s×300mm×300mm=0.63m ³ /s. The present invention has a total of five flow channels, and the fluid volume that should flow through each flow channel is 0.126m ³ /s. Therefore, as long as the integration is carried out sequentially along the width of the pipeline from the left end to the right end in Figure 4, the integration stops when the integral value reaches 0.126m3/s. By calculation, when the width reaches 80mm, 40mm, 50mm, 60mm, and 70mm respectively from left to right, the volumetric flow integral values in each flow channel are all 0.126m ³ /s (at this time, the average flow velocity in the five flow channels in turn 5.25m/s, 10.5m/s, 8.4m/s, 7m/s, 6m/s). In this way, it can be determined that the sizes of the inlets of the five fluid channels are 80mm×300mm, 40mm×300mm, 50mm×300mm, 60mm×300mm, and 70mm×300mm from left to right. Through this fluid cutting, the fluid flow in the five fluid channels is equal, so the outlet sizes of the fluid channels are also equal, and the outlet sizes of the fluid channels are 60mm×300mm, 60mm×300mm, 60mm×300mm, 60mm× 300mm, 60mm×300mm (at this time, the average flow velocity in the five flow channels is 7m/s).

In probability theory and mathematical statistics, variance (English Variance) is used to measure the degree of deviation between a random variable and its mathematical expectation (ie, mean). In many practical problems, it is of great significance to study the degree of deviation between a random variable and its mean.

${\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="S"\; filenames="101026214530.png"\; state="\{\{state\}\}">S</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; [</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; -</span>\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; ]</span>$

Therefore, in order to analyze the difference between the present invention and the velocity distribution at the outlet of the traditional T-shaped diverter tee, the concept of variance is introduced here to analyze the flow velocity stability.

The present invention is compared with the velocity variance of the traditional T-shaped diverter tee. The variance of the cross-sectional velocity of the pipeline at the outlet of the traditional T-shaped diverter tee is 1.265459, and the variance of the cross-sectional velocity of the pipeline at the outlet of the present invention is 0.791196. Its speed stability is increased by 37.5%.

At the same time, by collating the cross-sectional velocity distribution values of the present invention and the traditional T-shaped shunt tee, as shown in FIG. 5 . The velocity distribution at the outlet of the present invention is obviously more uniform than that of the traditional elbow, which not only avoids the vibration noise caused by the uneven flow velocity distribution of the fluid in the pipe, but also stabilizes the airflow entering the air-conditioned room, improving the comfort of the living space.

Claims (5)

1. rectangular cross section T type shunting rectification threeway; Comprise entrance (1) and two outlet sections (5,10); One of them outlet section (10) is on the same horizontal plane with entrance (1); The plane, elongation line place of another outlet section (5) constitutes the T font structure perpendicular to plane, entrance (1) place, and it is characterized in that: entrance (1) links to each other with an outlet section (10) through the horizontal connecting end of shunting section (2); Vertical connecting end of shunting section (2) links to each other with breeze way (9), is provided with the rectification section (11) that links to each other with another outlet section (5) in breeze way (9) downstream; The interior upstream extremity of described rectification section (11) is provided with straightener(stator) blade (3,6,7,8), has guide vane (4) on each straightener(stator) blade with being divided into five fluid passages of waiting flow in the rectification section (11).

2. rectangular cross section T type shunting rectification threeway according to claim 1, be characterised in that: breeze way (3) length is identical with entrance (1) channel width.

3. rectangular cross section T type shunting rectification threeway according to claim 1; Be characterised in that: it vertically is acute triangle to described straightener(stator) blade (3,6,7,8) along rectification section (11); And with coming flow path direction certain inclination angle is arranged, make to form five fluid passages that inlet varies in size in the rectification section (11).

4. rectangular cross section T type shunting rectification threeway according to claim 1, be characterised in that: described guide vane (4) comes flow path direction to be acute triangle dorsad, and vertically is parallel to each other with rectification section (11).

In the rectangular cross section T type shunting rectification threeway rectification section (11) that designs claim 1 each straightener(stator) blade (3,6,7,8) and rectification section (11) vertically between the method for inlet of five fluid passages of formation; It is characterized in that this method comprises the steps:

Step 1, confirm the fluid flow fields state in the rectangular cross section T type diversion three-way: according to two outlet sections (5,10) line size and entrance liquid speed; The operation reynolds stress model also combines the SIMPLE algorithm; Simulate then velocity field in rectification section (11) the front T type diversion three-way pipeline is set, thereby obtain the velocity distribution of rectification section (11) position fluid;

The inlet of step 2, five fluid passages confirming to form between rectangular cross section T type shunting rectification each straightener(stator) blade of threeway (3,6,7,8) and rectification section (11) longitudinal direction is big or small; The velocity distribution of rectification section (11) the position fluid of trying to achieve according to step 1; Utilize area branch principle, try to achieve five fluid passages inlet sizes when satisfying each fluid passage inner fluid flow the same terms.

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