Method for ventilating and cooling a factory building

Abstract

The application relates to a plant ventilation and heat dissipation method, which mainly comprises the following steps: a plant overall parameter design step, which theoretically estimates and adjusts total air demand, total window area, window air outlet speed and indoor and outdoor pressure difference; an air outlet pipeline geometric design step, which preliminarily designs according to the basic principle of fluid mechanics, and then calculates the pipeline geometric size by using a computer program, so that the maximum air speed or flow unevenness of each air outlet reaches a satisfied low value; and a plant pipeline position configuration design step, which estimates and adjusts the flow field, temperature field and concentration field in the plant by using a computer program, and is used for adjusting the pipeline installation horizontal position, height and window height, so that the air speed, temperature and concentration in the plant reach the required values, and the dust floating into the plant is blocked, and the temperature and pollutant concentration in the plant are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for ventilating and cooling a factory building, and more particularly to a method for ventilating and cooling a factory building that can effectively prevent dust from entering the factory building and reduce the temperature and even the concentration of pollutants in the factory building. BACKGROUND

[0002] For a general factory operation building, if the number of workers in the building is large, the heat generated by the machines cannot be removed to the outside of the building, and the heat will cause the temperature in the building to rise. When the building needs to maintain a low dust level, using a general air suction ventilation method will make it easy for dust to be sucked into the room from the open windows and doors.

[0003] For example, for a factory that manufactures plastic bags, there are heat-generating machines inside, and it is necessary to maintain a low dust level to prevent sticking to the plastic bags. Therefore, all windows are closed, leaving only louvered windows on the upper wall. This results in high temperatures in the factory building, individual plastic bags are difficult to separate, and dust cannot be avoided. Another example is a factory that manufactures shoes and belts, which has heat-generating machines inside and needs to maintain a low dust level to prevent sticking to the shoes and belts during "glue pressing". The factory closes all the windows on the left and right walls, but to ventilate and prevent high temperatures in the factory, it installs multiple exhaust fans on the rear windows and opens the doors and windows on the front wall. However, except for the area near the doors and windows on the front wall, there is almost no wind in most areas of the factory, so many "relay fans" are installed on the upper part of the factory. It is intuitively believed that this will make the air flow smoothly from the doors and windows on the front wall to the exhaust fans on the rear windows. As a result, a large amount of dust will be sucked into the factory building from the doors and windows on the front wall, and the temperature in the factory building will still be high. If a filter screen is installed on the windows and doors to filter dust, the pressure loss caused by the blockage of the filter screen will greatly reduce the flow rate of the axial flow fan and increase the energy consumption. Not only is it time-consuming and labor-intensive to clean and maintain the filter screen, but it is also not very effective in preventing dust from entering the factory building. Therefore, it is practically difficult to install a filter screen on each open window and door.

[0004] Another way to deal with the "heat" and "dust" problem is to use the "dilution plenum method", which supplies filtered "cold", "warm" or "room temperature" clean air to the factory building by a fan, mixes (dilutes) with the original air in the room, adjusts the opening of the window sash, and causes sufficient pressure loss (resistance) when the air flow overflows the window sash opening to block dust from entering the factory building and reduce the temperature and even the concentration of pollutants in the factory building. However, the basic dilution method principle in traditional ventilation textbooks and manuals basically assumes that the spatial distribution of the concentration of pollutants in the room at any instant is "uniform". However, this cannot be applied to the complex situation of an actual factory. SUMMARY

[0005] In view of this, in order to provide a structure that is different from the prior art and to improve the above-mentioned shortcomings, the inventors of this application have accumulated many years of experience and continuous research and development, resulting in this application.

[0006] One objective of this application is to address the problem that existing ventilation and heat dissipation technologies are still unable to effectively prevent dust from entering the factory and reduce the temperature and pollutant concentration inside the factory in practical applications. Instead, it provides a factory ventilation and heat dissipation method that can achieve a positive pressure effect inside the factory, making the pressure inside the factory higher than the atmospheric pressure outside the factory, thereby effectively preventing dust from entering the factory and reducing the temperature and even the concentration of pollutants inside the factory.

[0007] To achieve the above objectives, a factory ventilation and heat dissipation method according to this application includes the following steps: A. Overall factory parameter design step, which theoretically estimates and adjusts the total required air volume, the total area of ​​at least one window, the air outlet velocity of at least one window, and the indoor-outdoor pressure difference; B. At least one duct geometry design step, which first performs a preliminary design based on the basic principles of fluid mechanics, and then uses a CFD computer program to calculate and design the geometry of at least one duct so that the maximum wind speed or flow rate non-uniformity of several air outlets reaches a satisfactory low value; C. At least one duct location configuration design step, which uses a CFD computer program to estimate and adjust the flow field, temperature field, and concentration field in the factory, and uses this to adjust the horizontal position and height of the installation of at least one duct and the height of at least one window so that the wind speed, temperature, and concentration in the factory reach the required values.

[0008] In practice, this application further includes a duct height and outlet geometry design step after step A, which uses a database to select and adjust the minimum duct installation height, outlet length, width, spacing ratio, number of outlets, and average outlet wind speed of at least one duct.

[0009] In practice, the side walls include a first side wall, a third side wall, a second side wall and a fourth side wall arranged sequentially, with the first side wall parallel to the second side wall.

[0010] During implementation, the first side wall and the second side wall each have at least one window for ventilation.

[0011] In practice, at least one pipe is connected to the first side wall at one end and the other end of at least one pipe is connected to the second side wall, so that at least one pipe is perpendicular to the first side wall and the second side wall respectively.

[0012] In practice, this application further provides at least one baffle, which is located at the same horizontal level as at least one pipe.

[0013] In practice, at least one partition is a flat plate with a high thermal insulation coefficient to block radiant heat emanating downwards from the roof.

[0014] During implementation, step A involves supplying filtered air from outdoors into the factory to dilute the high temperature and pollutant concentration inside the factory and to create a positive pressure environment inside the factory.

[0015] In practice, any pipeline has an upstream end and a downstream end, and the pipeline is divided into several gradually narrowing sections from the upstream end to the downstream end, with each section having at least one air outlet.

[0016] In practice, the velocity or flow rate of several air outlets of any pipe in step B is obtained by adjusting the ratio of the cross-sectional area of ​​any pipe to the total cross-sectional area of ​​the air outlets.

[0017] To further understand this application, preferred embodiments are described below, along with drawings and reference numerals, to explain in detail the specific composition and effects achieved by this application. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the factory exterior according to a preferred embodiment of this application.

[0019] Figure 2 for Figure 1 Side view.

[0020] Figure 3 This is a flowchart illustrating the overall parameter design of the factory building for step A of this application.

[0021] Figure 4 , Figure 5 This is a table of design parameters for the overall parameters of the factory building in step A of this application.

[0022] Figure 6 This is a schematic diagram of the design parameters for the height of the factory ductwork and the geometry and configuration of the air outlets in step B of this application.

[0023] Figures 7-9 This is a flowchart illustrating the geometric design of the plant duct height and air outlet in step B of this application.

[0024] Figure 10 This is a diagram defining the 50% non-uniformity in step B of this application.

[0025] Figure 11 , Figure 12 This is part of the database for step B of this application.

[0026] Figure 13 This is a schematic diagram of the blowing pipe with jet direction control for step C of this application.

[0027] Figure 14 This is a pipeline design flowchart for method (A) in step C of this application.

[0028] Figure 15Side view of the pipe divided into several sections from upstream to downstream for step C of the present application.

[0029] Figure 16 Original design of the air outlet pipe for step C of the present application.

[0030] Figure 17 Velocity field inside the adjusted pipe and outside the air outlet for method (A) of step C of the present application.

[0031] Figure 18 Static pressure distribution inside the adjusted pipe for method (A) of step C of the present application.

[0032] Figure 19 Maximum air velocity at each air outlet for method (A) of step C of the present application before and after adjustment. jm,i Statistical table.

[0033] Figure 20 Flow rate at each air outlet for method (A) of step C of the present application before and after adjustment. j,i Statistical table.

[0034] Figure 21 Percentage improvement of the overall non-uniformity of the maximum air velocity at the air outlets for method (A) of step C of the present application before and after adjustment.

[0035] Figure 22 Cross-sectional area of each section of the pipe for method (A) of step C of the present application before and after adjustment. duct,i Statistical table.

[0036] Figure 23 Design parameter table for the original pipe for method (A) of step C of the present application before adjustment.

[0037] Figure 24 Design parameter table for the adjusted pipe for method (A) of step C of the present application.

[0038] Figure 25 Design parameter table for the air outlet adjuster for method (A) of step C of the present application before and after adjustment.

[0039] Figure 26 、 Figure 27 Pipe design flowchart for method (B) of step C of the present application.

[0040] Figure 28 Pipe design for method (B) of step C of the present application.

[0041] Figure 29 Pipe design for case A of method (B) of step C of the present application.

[0042] Figure 30For step C of this application, the method (B) determines the maximum wind speed u at each air outlet before and after adjustment. jm,i Statistical table.

[0043] Figure 31 For step C of this application, the method (B) involves adjusting the airflow Q at each outlet before and after the adjustment. j,i Statistical table.

[0044] Figure 32 H is the method (B) of step C in this application. duct =2.0m Velocity field diagrams inside the duct and outside the air outlet before and after adjustment.

[0045] Figure 33 H is the method (B) of step C in this application. duct =2.0m Static pressure distribution diagram inside the adjusted pipeline.

[0046] Figure 34 The graph shows the percentage improvement in overall air outlet non-uniformity t before and after adjustment for method (B) in step C of this application.

[0047] Figure 35 This is a flowchart illustrating the design of step D in this application.

[0048] Figure 36 This is a tracking gas distribution diagram for step D of this application.

[0049] Figure 37 , Figure 38 This is a table of plant design parameters for step D of this application.

[0050] Figure 39 This diagram illustrates four different pipe configurations for step D of this application.

[0051] Figure 40 This is a case study of step D in this application, using a CFD computer program to analyze and calculate the statistical table of velocity, temperature, concentration, and pressure in the plant's operating area.

[0052] Figure 41 This is a schematic diagram of the exterior of a factory building, representing another example of a building with partitions in this application.

[0053] Figure 42 for Figure 41 Side view.

[0054] Figure 43 , Figure 44 This is a table of plant design parameters for another example of step D in this application.

[0055] Figure 45 This is another example of step D in this application, showing the velocity vector and streamline distribution in a cross section with y = 3m on the side elevation.

[0056] Figure 46 Temperature field distribution plot in the cross section of side elevation y=3m for another case of step D of the present application.

[0057] Figure 47 Concentration field distribution plot in the cross section of side elevation y=3m for another case of step D of the present application.

[0058] Figure 48 Velocity vector and stream line distribution plot in the cross section of end elevation y=3m for another case of step D of the present application.

[0059] Figure 49 Temperature field distribution plot in the cross section of end elevation y=3m for another case of step D of the present application.

[0060] Figure 50 Concentration field distribution plot in the cross section of end elevation y=3m for another case of step D of the present application.

[0061] Figure 51 Velocity vector and stream line distribution plot in the cross section of horizontal plane z=1.8m for another case of step D of the present application.

[0062] Figure 52 Temperature field distribution plot in the cross section of horizontal plane z=1.8m for another case of step D of the present application.

[0063] Figure 53 Concentration field distribution plot in the cross section of horizontal plane z=1.8m for another case of step D of the present application.

[0064] Figure 54 Statistical table of velocity, temperature, concentration, pressure in the plant operating area for another case of step D of the present application.

[0065] Figure 55 Comparison plot of average velocity between two cases of step D of the present application (without baffle and with baffle) and the original plant.

[0066] Figure 56 Comparison plot of temperature between two cases of step D of the present application (without baffle and with baffle) and the original plant.

[0067] Figure 57 Comparison plot of concentration between two cases of step D of the present application (without baffle and with baffle) and the original plant.

[0068] Figure 58 Comparison plot of pressure between two cases of step D of the present application (without baffle and with baffle) and the original plant.

[0069] Wherein, 1: plant 11: roof

[0070] 12: first side wall 13: third side wall

[0071] 14: second side wall 15: fourth side wall

[0072] 16: indoor space 17: duct

[0073] 170: section 171: air outlet

[0074] 18: window 19: partition. DETAILED DESCRIPTION

[0075] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0076] Referring to FIG. 1, Figure 1 、 Figure 2 The factory building 1 of the present application mainly comprises a roof 11, a first side wall 12, a third side wall 13, a second side wall 14 and a fourth side wall 15 which are sequentially and continuously arranged below the roof 11, the first side wall 12 and the second side wall 14 are parallel to each other. The four side walls frame a rectangle, and together with the roof 11 frame an indoor space 16, the indoor space 16 has at least one duct 17 above it, in the present embodiment, four ducts 17 are arranged side by side at intervals and are parallel to the third side wall 13 and the fourth side wall 15. Any duct 17 has an upstream end and a downstream end according to the flow direction of air, and is divided into several tapered sections 170 from the upstream end to the downstream end. The lower half of each section 170 of each duct 17 has at least one air outlet 171 arranged at intervals, respectively, for sending out the downward air flow; the first side wall 12 and the second side wall 14 respectively have a plurality of horizontally spaced windows 18 for respectively discharging air outward.

[0077] The method for ventilating and cooling the factory building of the present application comprises the following steps:

[0078] A. The overall parameter design step of the factory building 1, which theoretically estimates and adjusts the total air volume Q required total , the total area A of the window 18 win , the air outlet speed V of the window 18 win , the indoor and outdoor pressure difference ΔP win .

[0079] B. Duct 17 height and air outlet 171 geometry design step, which selects and adjusts at least one duct 17 duct installation minimum height h, air outlet 171 length d j , width w j , spacing ratio s j / d j , air outlet 171 number N j , air outlet 171 average wind speed u j .

[0080] C. Air outlet duct 17 geometry design step, which first makes a preliminary design based on the basic principles of fluid mechanics, and then calculates the duct 17 geometry (length L duct , width W duct , height H duct) ) using Computational Fluid Dynamics (CFD) computer program to make the maximum wind speed or flow rate non-uniformity of each air outlet 171 reach a satisfactory low value.

[0081] D. Plant 1 duct 17 position configuration design step, which estimates and adjusts the flow field, temperature field, and concentration field in the plant 1 using CFD computer program to adjust the installation horizontal position, height of the duct 17 and the height of the window 18, so that the wind speed, temperature, and concentration in the plant 1 reach the required values.

[0082] In cold or warm rooms, or hotel, public facilities hall often encounter the situation: in some places often cold, warm or room temperature high-speed airflow directly blows the head, in some places almost no wind, in some places too cold or too hot, making the human body uncomfortable, and even cause illness. These problems are caused by using thermodynamic principles for "cooling", "heating", but not using fluid mechanics principles for "air distribution" to guide and distribute airflow.

[0083] Step A is the overall parameter design step of the plant, which is based on thermodynamic principles and uses overall parameters to preliminarily estimate the required air volume; the overall parameter design flowchart of the plant 1 is shown in Figure 3 . The purpose of overall parameter design is to supply filtered air or cold air from the outside to the plant 1, dilute the high temperature and pollutant concentration in the plant 1, and make the plant 1 have a positive pressure. In this way, the temperature and pollutant concentration in the plant 1 can be reduced and diluted, and the opportunity of dust from the outside of the plant 1 entering the plant 1 through doors, windows, openings, and gaps can be reduced.

[0084] The overall parameter design method of the factory building 1 must consider the influence caused by the "heat generation rate" of the human body and the machine when designing the air intake. If the machine surface is well insulated, the machine exhausts heat and the pollutants are removed through the "local ventilation facilities", only the heat generated by the human body is considered, but the air intake of the "local ventilation facilities" must be added to the "required air intake" calculated below.

[0085] The "required air volume flow rate" estimation method includes:

[0086] 1. Thermodynamic estimation method: if there is a problem of "overheating" in the factory building, it is assumed that the air in the factory building maintains a homogeneous and equilibrium state during air supply, and the "theoretical required air volume flow rate" Q is estimated using the principle of "thermodynamics". theory If the total heat generation rate of the human body and the machine in the factory building is q, the specific heat of air at room temperature is c p , the density is p, the temperature of the air rising due to heat absorption in the factory is ΔT, the "theoretical required air mass flow rate" is m, and the "theoretical required air volume flow rate" is Q theory . According to the principle of "thermodynamics", the relationship between the above parameters can be written as:

[0087] q = mc p ΔT = (ρQ theory )c p ΔT,

[0088] Therefore, Q theory = q / (ρc p ΔT)

[0089] If the "permissible temperature rise" ΔT is set, the "theoretical required air volume flow rate" Q theory can be calculated according to the above formula. [Note: Set the permissible temperature rise of indoor air ΔT (e.g. 0.1°C, 0.2°C or 0.3°C), if a "cooler" is installed upstream of the air supply fan, the temperature in the factory building can be lower than the outside air temperature; if no "cooler" is installed, the lowest temperature in the factory building can be similar to the outside air temperature]. The "actual required air volume flow rate" Q total will multiply the "theoretical required air volume flow rate" Q theory by a safety factor k (≥ 1):

[0090] Q total = kQ theory

[0091] If the "permissible temperature rise" ΔT is set, the "actual required air volume flow rate" Q total can be calculated according to the formula on the previous page. And if Q totalIf the value of ΔT is too large and beyond the reasonable range, then the following three ways can be chosen to adjust to reduce Qtotal total

[0092] (a). Increase ΔT to an acceptable value to reduce Qtotal;

[0093] (b). Install a "cooler" upstream of the air supply fan. If the "cooler" is an air conditioner, then a small amount of "cool air" can be mixed into the supply air by using a bypass method, only to reduce the temperature of the supply air a little, so that ΔT has enough margin to adjust Qtotal. If the "cooler" is other types, the same effect can also be obtained;

[0094] (c). Install a "local ventilation facility" on the heat generating machine to reduce the value of Qtotal (but remember to add the suction amount of the "local ventilation facility" to the "required intake air volume" Qtotal calculated in the end).

[0095] 2. Estimation of the upper limit of the pollutant mass concentration requirement: If there is a problem of "excessive pollutant concentration" in the factory building, it is assumed that the air in the factory building maintains a homogeneous and equilibrium state during the air supply process. The upper limit of the pollutant mass concentration requirement fp and the mass generation rate mp of the pollutant are used to estimate the "theoretical required air mass flow rate" m:

[0096] f p = m p / (m+m p ),

[0097] Therefore m = m p (1-f p ) / f p

[0098] Then divide the "theoretical required air mass flow rate" m by the density of the supply air ρ, and the "theoretical required air volume flow rate" Q theory can be obtained:

[0099] Q theory = m / ρ

[0100] Then calculate the "actual required air volume flow rate" Q total using the equation Q total = kQ theory .

[0101] 3. Adjust the total window opening area A win of the factory building to change the air "wind speed flowing out of the window to the outside" V win ​and "positive pressure" (excess pressure inside the factory over the outside air pressure) ΔP win Size. Air flow rate V win :

[0102] V win = Q total / A win

[0103] "positive pressure" ΔP win inside the factory: Assume the pressure loss coefficient of the window C0≈0.5-0.6,

[0104] ΔP win = C0(ρV win 2 ) / 2

[0105] 4. Try several times to calculate the total window opening area A win , even adjust ΔT, so that Q total and the positive pressure ΔP win and the wind speed V win reach a reasonable value.

[0106] Example of overall factory parameter design: A factory for manufacturing plastic bags, (length L x width W x height H) = (15 m, 12 m, 15 m). There are 4 heat generating machines (total heat generating rate q = 5 kW), which must be kept in a low dust state to prevent sticking to the plastic bags. The temperature difference ΔT < 0.5°C between the inside of the factory and the outside air is desired to maintain product quality. Please use the [Step A] design method of the dilution plenum method to set the "permissible temperature rise" ΔT = 0.2°C, and calculate: (1) "actual total air intake requirement" Q total , (2) total window opening area A win , (3) air flow rate V win from the window out of the factory, (4) "positive pressure" ΔP win inside the factory.

[0107] The calculation procedure is as follows:

[0108] <1> Estimate the "theoretical air intake requirement" Q theory using Q p = q / (ρc theory ΔT):

[0109] q = 5 kW, ρ = 1.164 kg / m 3 , c p = 1.007 kJ / kg*K,

[0110] Assuming ΔT = 0.2°C, substitute into the above equation to get

[0111] Q theory= 5 / [1.164 x 1.007 x 0.2] x 60 = 1280 CMM

[0112] Calculate "total air supply of the workshop" Q with safety factor k = 1.2 total , then

[0113] Q total = kQ theory = 1.2 x 1280 = 1536 CMM

[0114] <2> Assume "total area of the window opening" A win = 6 m 2 , use V win = Q total / A win to estimate "air flow velocity from the window out of the workshop" V win :

[0115] V win = [1536 / 60] / 6 = 4.27 m / s

[0116] <3> Assume the pressure loss coefficient of the window C0 ≈ 0.5, use ΔP win = C0 (pV win 2 / 2 to estimate "pressure difference between inside and outside of the workshop" ΔP win :

[0117] ΔP win = 0.5 x (1.164 x 4.27 2 / 2 = 5.31 Pa

[0118] According to the above calculation procedure, assume several different A win , calculate the corresponding (V win , ΔP win ), the results are as follows:

[0119]

[0120]

[0121] From the calculation results in the above table, if take (A win , V win , ΔP win ) = (5 m 2 , 5.12 m / s, 7.63 Pa) or (6 m 2 , 4.27 m / s, 5.31 Pa) combination, then:

[0122] 1. A winNot too big, (0.6m wide x 0.7m high) windows 12 or (0.625m wide x 0.8m high) windows 12, can be appropriately arranged in the two end walls of the factory building.

[0123] 2. Airflow velocity V out of the window win Appropriate (3m / s < V < 6m / s). win <6m / s).

[0124] 3. Pressure difference ΔP inside and outside the factory building win Sufficiently effective to block dust from escaping into the factory building (4Pa < ΔP < 8Pa). win <8Pa).

[0125] Through the above calculation results, the design parameter table of the overall parameters of the factory building can be obtained as shown in Figure 4 , Figure 5 .

[0126] Steps B, C, and D are techniques for guiding and distributing airflow, which require details of "fluid mechanics", and step B is a pipe height and air outlet geometry design step, which aims to:

[0127] 1. After the airflow is sprayed from multiple side-by-side air outlets of the pipe, a certain distance is needed for divergence when it reaches the head of a person, in order to reduce the "airflow average velocity at the head of a person " and "airflow velocity spatial distribution non-uniformity " to target values, so as not to make people feel uncomfortable:

[0128] (1). The head of a person is blown by high-speed airflow for a long time (especially cold air), and the airflow average velocity at the height of the head of a person

[0129] (2). If the "airflow velocity spatial distribution non-uniformity " is too large, the jet velocity is too large below the air outlet; the airflow velocity is too small in areas deviating from below the air outlet. The airflow velocity spatial distribution non-uniformity at the height of the head of a person (also can be defined as non-uniformity tolerance value) should be as small as possible.

[0130] 2. The pipe's [air outlet average wind speed u j , air outlet geometry (length d j , width w j , spacing ratio s j / d j )] will affect the size of the "multiple jet divergence distance". Therefore, CFD calculation analysis is needed to establish a database (Data Bank) for designing the desired airflow average velocity ratio at the height of the head of a person and acceptable spatial distribution non-uniformity The derivation distance (i.e., the minimum distance y* from the air outlet to the top of a person's head). The installation height h of the duct should be equal to or greater than the height h of a person. p Add the minimum distance y* from the air outlet to the top of a person's head, that is: h≥h p +y*.

[0131] 3. Obtain the number of pipes N according to [Step B]. duct Minimum duct installation height h, air outlet length d j Width w j Spacing ratio s j / d j Average velocity u at the air outlet j After that, proceed to [Step 3] to design the pipe geometry (L) duct W duct H duct This is to ensure that the air velocity uniformity at the air outlet meets the requirements.

[0132] 4. In some cases, such as when it is not necessary or desired to consider the non-uniformity of the jet spatial distribution. If there is no need to or no desire to worry about high-speed jets directly impacting a person's head, then step [B] can be omitted, and the appropriate number of pipes N can be directly set. duct Average wind speed at the air outlet, u j , length of air outlet d j Width w j Spacing ratio s j / d j First, determine the minimum installation height h for the ductwork, and then proceed to [Step C].

[0133] like Figure 6 As shown, it is a schematic diagram of the design parameters for the height of the factory's ductwork and the geometry and configuration of the air outlets.

[0134] Figures 7-9 A flowchart for the design of factory duct height and air outlet geometry.

[0135] Figure 10 The diagram defines the 50% non-uniformity.

[0136] Figure 11 , Figure 12 This is a partial database (Data Bank).

[0137] Example of factory duct height and outlet geometry design: In the design example of step A, the required Q for a plastic bag factory with (length L × width W × height H) = (15m, 12m, 15m) to achieve ΔT = 0.2℃ has been obtained. total= 1536 CMM. Please design the following parameters by the method of [Step B] of the dilution plenum method: the minimum height of duct installation h, the length of outlet d j , the width w j , the spacing ratio s j / d j , the number of outlets N j , the total area of outlets A j , the average air speed of outlets u j , so that the average air speed of the head height of the human body The spatial distribution of air speed is not uniform

[0138] The calculation program is as follows:

[0139] 1. Select a suitable number of ducts N total according to the required air volume Q duct estimated in [Step A] duct :

[0140] Q total = 1536 CMM, and assume that the number of ducts N duct = 4, then

[0141] Q total = 1536 / 4 = 384 CMM.

[0142] 2. Select the height of the human head h duct = 1.8 m:

[0143] Select the minimum height of the duct to be installed h = 7 m, then y* = h - h duct = 7 - 1.8 = 5.2 m.

[0144] 3. Select the length of the outlet d p = 0.3 m, and calculate y* / d p :

[0145] y* / d j = 5.2 / 0.3 = 17.33.

[0146] 4. Find the available range of s j / d j from the 50% non-uniformity boundary graph:

[0147] s j / d j ≤ 5.84.

[0148] 5. Select a s j / d j value, and calculate d j according to the value of s j / dj y* / d j h / d j The values ​​are used to confirm the spatial non-uniformity of airflow velocity distribution in Data Bank A.

[0149] Select "Outlet Spacing Ratio" j / d j =5, based on d j y* / d j s j / d j The numerical values ​​were used to confirm the spatial non-uniformity of airflow velocity distribution in database A. This is acceptable.

[0150] 6. Calculate s j :

[0151] s j =(s j / d j )×d j =5 × 0.3 = 1.5m.

[0152] 7. Calculate the number N of air outlets in the duct. j :

[0153] Pipe length L duct =15m (same as the factory building length), set the air outlets near the walls on both sides of the duct to be 2m away from the walls. Calculate N. j =[(15-2×2-0.3) / 1.5]+1=8.13. Choose N. j =9 → Acceptable.

[0154] 8. Using the selected N j Recalculate s j :

[0155] With N j =9 calculations s j =[(15-2×2-0.3) / (9-1)]=1.338m, so s j / d j =1.338 / 0.3=4.46.

[0156] With d j y* / d j s j / d j The corresponding spatial distribution non-uniformity of airflow velocity was confirmed again in the data bank.

[0157] 9. Based on s j / dj , d j , y* / d j , h / d j , the value of the corresponding average air flow velocity ratio in the Data Bank B Obtain

[0158] 10. Set the desired average air flow velocity at the human head Calculate

[0159] Set the desired average air flow velocity at the human head Calculate

[0160]

[0161] Take w j = 0.5 m → acceptable.

[0162] Recalculate

[0163]

[0164] 11. Calculate A j = d j × w j = 0.3 × 0.5 = 0.15 m 2 .

[0165] 12. Calculate A j,total = N j × A j = 9 × 0.15 = 1.35 m 2 .

[0166] 13. Calculate u j = Q duct / A j,total = 384 / 60 / 1.35 = 4.74 m / s → acceptable.

[0167] 14. Use the obtained duct installation minimum height h = 7 m, outlet length d j = 0.3 m, width w j = 0.5 m, spacing ratio s j / d j = 4.46, outlet number N j = 9, outlet average air speed u j = 4.74 m / s to design the duct geometry at [Step C].

[0168] Step C is the air duct geometry design step, which aims to send air into the duct and then eject it from the "air outlet" set at different positions along the length of the duct (for example, in the application of heating, ventilation and air conditioning: air supply duct of ventilation system, duct for sending cold or warm air to various places, etc.). If the duct flow, duct size, air outlet velocity or flow uniformity are not properly designed, in most applications that deliver sufficient air volume, the static pressure distribution in the duct increases from upstream to downstream, resulting in an increase in the jet velocity of the air outlet from upstream to downstream, that is, it is not easy to obtain "uniform distribution" of the ejected air flow, and the jet direction is not easy to control. Therefore, a set of methods are needed to obtain acceptable "air flow distribution" and "direction adjustment".

[0169] The duct air outlet velocity direction adjustment method is shown in Figure 13 , the air outlet jet direction is controlled by an empty pipe or guide vane. Using CFD calculation, the length of the guide vane and the gap between adjacent guide vanes are adjusted to achieve the target value. The duct air outlet velocity or flow uniformity adjustment method includes: [Method (A)] adjusting the duct cross-sectional area A duct from upstream to downstream, and [Method (B)] adjusting the duct cross-sectional area A duct and the total cross-sectional area of the air outlet A j,total in proportion. Among them, [Method (A)] adjusts the duct cross-sectional area A duct from upstream to downstream to adjust the static pressure distribution in the duct, thereby adjusting the air outlet velocity or flow uniformity. [Method (B)] adjusts the duct geometry (width W duct , height H duct ), flow Q duct , number N duct , and air outlet geometry (length d j , width w j , spacing s j ), number N j to improve the uniformity of the static pressure distribution in the duct, thereby improving the uniformity of the jet velocity of each air outlet. This method can obtain a high uniformity of the velocity and flow of each air outlet.

[0170] As shown in Figure 14 , it is a duct cross-sectional area A duct from upstream to downstream tapering method. As shown in Figure 15 , in the initial design, the duct is divided into several sections from the upstream end to the downstream end. Assuming that the velocity of each air outlet is u j = Q duct / A j,total , and the velocity of each section of the duct is the inlet velocity of the duct u duct , then according to the law of conservation of mass, the initial cross-sectional area A duct,i of each section of the duct is determined.

[0171] Assume the airflow is ideal fluid, no pressure loss when flowing in the pipe, then Bernoulli's principle (Bernoulli's principle: no water static pressure P hs = γh changes, dynamic pressure P v + static pressure P s = constant), if the speed of each section of the pipe is u duct , then the dynamic pressure P v in each section of the pipe is equal, so the static pressure P s in each section of the pipe is also equal (that is: the total pressure of each section of the pipe is equal); consider the Bernoulli's principle again at the outlet: when the static pressure in each section of the pipe or the static pressure near the outlet of the pipe P s is equal, the speed u j of each outlet is the same. Therefore, according to the law of conservation of mass and Bernoulli's principle, the speed of each section of the pipe is u duct and the speed of each outlet is u j = Q duct / A j,total , so the initial cross-sectional area of each section of the pipe can be determined.

[0172] It is more appropriate to arrange an outlet in a section of the same cross-sectional area pipe. If the pipe is too long or there are too many outlets, several outlets can be arranged in a section of the same cross-sectional area pipe; but when arranged in this way, the outlet air speed of the upstream outlet will be lower than that of the downstream outlet in the same section of the same cross-sectional area pipe.

[0173] Furthermore, since real fluid must have viscosity, there must be pressure loss when flowing through each section of the pipe, so it must be corrected. Calculate the flow field distribution by CFD, adjust the cross-sectional area A duct,i of each section of the pipe according to the flow field calculation results, so that the speed u j of each outlet is uniform. Usually, the flow field distribution calculated by the initial cross-sectional area A duct,i has a certain degree of uniformity at the upstream and middle outlets of the pipe, but the jet speed of the several downstream outlets is smaller than that of the upstream and middle outlets. If A duct,i is adjusted (while A duct,i is reduced upstream and A duct,i is increased downstream), the uniformity of the outlets of the entire pipe can be improved.

[0174] If several outlets are arranged in a section of the same cross-sectional area pipe, the outlet air speed of the upstream outlet will be lower than that of the downstream outlet in the same section of the same cross-sectional area pipe. To correct this problem, the section of the same cross-sectional area pipe can be changed to gradually decrease downstream. In addition, a certain Q ductAfter completing the pipe and outlet configuration and geometry according to [Method (A)] and obtaining satisfactory outlet velocity uniformity, if Q is changed within a certain range... duct If the value is changed, the air outlet velocity unevenness will only change slightly. For example, in the following case A, the original Q... duct Within 0.4 to 5 times the value, the change in uniformity can be roughly ignored.

[0175] Maximum velocity u at each duct outlet jm,i non-uniformity η t definition:

[0176]

[0177] u jm,i Maximum speed of each air outlet

[0178] u jm,ave The average maximum velocity of all air outlets

[0179] The flow rate Q at each duct outlet j,i non-uniformity η t definition:

[0180]

[0181] Q j,i The airflow of each air outlet

[0182] Q j,ave Average airflow from all air outlets

[0183] For example: 18m duct (9 air outlets in total, Q) duct =5.4m 3 / s) After the design is improved, if the flow rate is changed but the same design is maintained, the non-uniformity η t,u The changes are not significant, as shown in the two tables below.

[0184]

[0185]

[0186] Maximum variation (%): The difference between the maximum and minimum air velocity at all air outlets of the duct, divided by the average value.

[0187] Among them, the cross-sectional area A of each section of the pipeline duct,i The adjustment principles are as follows:

[0188] 1. Increase A duct,i It can increase the maximum speed of the air outlet. jm,i ; Decrease A duct,i It can reduce the maximum air velocity at the outlet. jm,i .

[0189] 2. Compare each outlet maximum velocity u jm,i with all outlet maximum velocity average u jm,ave ,

[0190] If u jm,i > u jm,ave → increase A duct,i ;

[0191] If u jm,i < u jm,ave → decrease A duct,i .

[0192] Adjust back and forth until acceptable velocity distribution is obtained.

[0193] Case A: One air duct original design as list in Figure 16 , after CFD analysis of original duct inner and outlet velocity field, each outlet velocity is very uneven. Please design to increase each outlet velocity uniformity by method (A).

[0194] Adjustment design process as follows:

[0195] 1. L duct = 18 m, divided into 9 sections, each section with one outlet.

[0196] 2. After 4 adjustment design, duct inner and outlet velocity field as shown in Figure 17 , each outlet velocity distribution is more uniform; duct inner static pressure distribution as shown in Figure 18 , static pressure in the area above the outlet is more uniform.

[0197] 3. Figure 19 , Figure 20 is the adjustment process statistics table, in which, Figure 19 is the maximum outlet velocity u jm,i statistics table, according to the initial design based on "conservation of mass" and "Bernoulli's law", the "straight pipe" "each outlet velocity is very uneven" problem has been greatly improved, but the outlet velocity distribution becomes: the upstream outlet velocity is larger than the downstream, and the last few outlet velocities become too small. And in succession according to the initial design to adjust the pipe size (reduce the size of the upstream pipe, increase the size of the downstream pipe), that is, the initial design can be effectively corrected, and the comparison η t,u0 = 40.0%.

[0198] 4. Figure 20 is the outlet flow Q j,i statistics table, in which, the uniformity of u jm,i and Q j,i may not be considered, it is best to select ujm,i or Q jm,i As the criterion of uniformity, the design program of adjusting the cross-sectional area of each pipe section is performed, which compares η t,Q0 = 61.4%.

[0199] 5. Figure 21 The total non-uniformity η t of the maximum air velocity of the outlet is improved by percentage.

[0200] 6. Figure 22 The cross-sectional area A duct,i of each pipe section is calculated. duct,1 ~ A duct,3 is smaller than the initial design A duct,i (#0); while A duct,4 ~ A duct,9 is larger than the initial design A duct,i (#0).

[0201] 7. Figures 23-25 The pipe design parameter table is arranged. Wherein, Figure 23 is the original pipe design parameter, Figure 24 is the adjusted pipe design parameter, and Figure 25 is the design parameter of the outlet adjuster.

[0202] As shown in Figure 26 , Figure 27 is the pipe design flow chart of the ratio method of the cross-sectional area A duct of the pipe to the total cross-sectional area A j,total of the outlet. As shown in Figure 28 , for the selected L duct , by adjusting the pipe geometry (W duct , H duct ), flow Q duct , number N duct and outlet geometry (d j , w j , s j ), number N j , the type of static pressure distribution in the pipe [from the bottom layer (outlet side) to the upper layer (outlet opposite direction)] can be changed, thus improving the jet velocity uniformity of each outlet. The parameters affecting the jet velocity uniformity of each outlet of the pipe are listed as follows:

[0203]

[0204]

[0205] After obtaining Q total from [step A], L duct is determined according to the size of the plant.and set the initial N duct . Then consider the following parameter adjustment:

[0206] 1. Let u duct / u j ≤ 1.2 (i.e. A duct / A j,total ≥ 1.2), acceptable uniformity can be generally obtained. The larger A duct / A j,total is, the higher the uniformity is; after A duct / A j,total ≥ 1.6, the uniformity of each outlet velocity is usually quite high.

[0207] 2. The critical value of A duct / A j,total has relevance to the pipe length L duct , the outlet size (d j , w j ), and the flow rate Q duct . The general rule is:

[0208] <1> The shorter the pipe length L duct is, the smaller the critical A duct / A j,total is.

[0209] <2> The smaller the outlet width w j is, the smaller the non-uniformity η t is.

[0210] <3> The smaller the outlet length d j is, the smaller the non-uniformity η t is.

[0211] <4> The smaller the flow rate Q duct is, the smaller the critical A duct / A j,total is.

[0212] 3. After the pipe and outlet configuration and geometry are designed according to [Method (B)] to obtain satisfactory outlet velocity uniformity using a certain Q duct value, if the Q duct value is to be changed, the outlet velocity non-uniformity will only change slightly, which can be ignored.

[0213] 4. When the outlet axial length d j , the lateral width w j , the distance between adjacent outlets s j / d j , and the pipe length L duct are fixed, if the pipe cross-sectional area A duct (i.e. H duct × W duct) the greater, the flow Q duct (That is: u duct ) the smaller, N duct ) the greater, that is: the wind speed u duct ) the smaller, the easier the uniformity of the velocity of each outlet.

[0214] 5. Under the conditions of a fixed duct height H duct , width W duct and single duct flow Q duct , duct length L duct , if the outlet area A j ( = d j x w j ) is smaller and the number of outlets N j is fewer, the velocity of each outlet is easier to be uniform.

[0215] When [Method (B)] is used, a high uniformity of each outlet can be obtained, and because the pressure distribution form is changed, the uniformity of u jm,i and Q jm,i (that is: the average velocity) can be taken into account. However, an excessively large duct cross-sectional size is often obtained, and the production and installation are sometimes inconvenient. If the duct size (W duct , H duct ), N duct or the outlet geometry (d j , w j , s j ), N s is adjusted multiple times, the result is still not satisfactory [for example: (W duct , H duct ) is too large, (d j , w j , s j ) is too small], a more acceptable CFD design is adopted, and a mechanical control method using outlet dampers or damper grids is used to adjust the uniformity of the velocity of each outlet of the duct when the preliminary air supply of the duct is completed.

[0216] In practice, the method of adjusting the outlet dampers or damper grids of the duct is to start from the outlet at the most downstream end (the end of the duct), first adjust the wind speed of the outlet at the most downstream end to u j , then sequentially adjust the wind speed of each outlet to u j upstream, until the outlet at the most upstream end; then return to the outlet at the most downstream end, fine-tune to u j , and continue to sequentially adjust the wind speed of each outlet to u j upstream. After several rounds of adjustment, the wind speed of each outlet can be close to uniform.

[0217] Case A: The duct design is as follows Figure 29The listed original duct pipe, the velocity field inside and outside the air outlet after CFD analysis, the air outlet velocity of each air outlet is extremely uneven. Please use method (B) to increase the air outlet velocity of each air outlet. duct The total cross-sectional area of the air outlet A j,total The proportional method is designed to increase the uniformity of the air outlet velocity of each air outlet.

[0218] And the adjustment process statistics table of the designed is as shown in Figure 30 、 Figure 31 , wherein, Figure 30 is the maximum air speed u jm,i The statistical table of the original duct (#0) duct cross-sectional area A duct The total cross-sectional area of the air outlet A j,total The proportion is too small (A duct / A j,total =0.3) and the air outlet velocity uniformity is low. After adjustment, the duct H duct The proportion of the duct cross-sectional area A duct The total cross-sectional area of the air outlet A j,total is also increased (A duct / A j,total ), and the air outlet velocity uniformity is also improved. Figure 31 is the flow rate Q j,i The statistical table of each air outlet after adjustment can obtain a high uniformity of each air outlet, and because the pressure distribution form is changed, the uniformity of u jm,i and Q jm,i (that is: average velocity) can be considered.

[0219] Figure 32 The velocity field inside and outside the air outlet of the duct designed after H duct =2.0m adjustment shows that the air velocity uniformity of each air outlet is high. Figure 33 The static pressure distribution inside the duct designed after H duct =2.0m adjustment shows that the static pressure is distributed in layers [changes from the bottom layer (air outlet side) to the upper layer (air outlet opposite direction)]. And Figure 34 is the overall non-uniformity η t of the air outlet before and after adjustment, which shows that the overall uniformity of the air outlet is greatly improved after adjustment.

[0220] Step D is the position configuration design step of the factory building duct, and the design flow chart is as shown in Figure 35 . The purpose of the design of the factory building duct position is: after steps A, B, C, the required total air volume Q total , the total area of the window A win , the air volume of a single duct Q duct , the number of ducts N duct , the geometric size of the duct (Lduct ,W duct ,H duct ), outlet length d j , width w j , spacing ratio s j / d j , number of outlets N j , minimum height of duct installation h. Step D is necessary to adjust the horizontal position, height of duct installation and the window configuration / height. Since the horizontal position, height of duct installation and the window configuration / height will affect the flow pattern of the air flow in the plant, in turn affecting the distribution of temperature, concentration. If not properly designed, the velocity, temperature, concentration distribution in the plant can be extremely uneven. This step uses CFD to calculate and adjust the flow field, temperature field, concentration field in the plant, so that the wind speed, temperature, concentration in the plant reach the required distribution and value.

[0221] The design principles of plant duct configuration are as follows:

[0222] 1. Installing a baffle at the lower edge of the duct can greatly improve the flow field, temperature field, and concentration field of the work area compared to the condition without the baffle.

[0223] 2. The configuration method of concentrating the distribution of ducts on one side of the plant will cause large backflow bubbles in the plant. Compared with the average distribution of ducts in the plant or the concentration of ducts in the central area, the air flow in the work area has a higher average speed, but the pollutant concentration distribution is higher and less uniform.

[0224] 3. The average distribution of ducts in the plant or the concentration of ducts in the central area will cause many small backflow bubbles in the plant. Compared with the concentration of ducts on one side of the plant, the air flow in the work area has a slightly lower average speed, but the average concentration of pollutants is lower and more uniform.

[0225] 4. The average temperature of the work area obtained by the configuration method of evenly distributing the ducts in the plant is similar to that obtained by the configuration method of concentrating the ducts on one side or in the central area of the plant, but the temperature field of the work area obtained by the configuration method of evenly distributing the ducts in the plant and concentrating the ducts in the central area is slightly more uniform than that obtained by the configuration method of concentrating the ducts on one side of the plant.

[0226] 5. Comparing the flow field, temperature field, and concentration field distribution and value of the work area, the order of the advantages and disadvantages of the distribution method of the ducts is:

[0227] <1> Concentrated in the central area.

[0228] <2> Average distribution in the plant.

[0229] <3> Concentrated on one side of the plant.

[0230] 6. Reducing the outlet temperature of the ducts near the heat source can reduce the average temperature of the work area and also reduce the temperature of the heat generating machine.

[0231] 7. The relative orientation of the ducts and the windows affects the flow field, temperature field, and concentration field. The average velocity, temperature, and concentration in the working area are similar for the cases of "windows installed on the wall surface perpendicular to the duct axis" and "windows installed on the wall surface parallel to the duct axis"; however, the local concentration field and temperature field distribution are better for the case of "windows installed on the wall surface perpendicular to the duct axis" than for the case of "windows installed on the wall surface parallel to the duct axis".

[0232] 8. If the height of the windows is adjusted from below the wall surface to above the wall surface, the flow field, temperature field, and concentration field in the working area are slightly degraded (the difference is not large).

[0233] 9. In the design, the gap between adjacent windows is as small as possible.

[0234] Example of the design of the location and configuration of the ducts in a factory: A factory for manufacturing plastic bags (length L x width W x height H) = (15 m, 12 m, 15 m). There are four heat-generating machines (total heat generation rate q = 5 kW), and the dust must be kept low to prevent sticking to the plastic bags. The temperature difference ΔT between the temperature in the factory and the temperature of the outside air is desired to be less than 0.5°C to maintain the quality of the product.

[0235] In which, the design method of [steps A, B, C] of the dilution and pressurization method is used to obtain:

[0236] Step A: (Q duct , A win , V win , ΔP win ) = (1536 CMM, 6 m 2 , 4.27 m / s, 5.31 Pa); there are 12 windows, each of which has a width of 0.625 m and a height of 0.8 m.

[0237] Step B: the number of air ducts N duct = 4, the flow rate of each air duct Q duct = 384 CMM, the minimum installation height of the air duct h = 7 m, the length of the air outlet d j = 0.3 m, the width of the air outlet w j = 0.5 m, the spacing ratio s j / d j = 4.46, the number of air outlets N j = 9, and the average air outlet velocity u j = 4.74 m / s.

[0238] Method A of Step C: The cross-sectional area A duct of the ducts is designed to gradually decrease from upstream to downstream, so that the maximum velocity of each air outlet is uneven by 3.4%, and the air outlet flow rate of each air outlet is uneven by 11.8%.

[0239] Tracking gas release method:

[0240] 1. Tracking gases: such as Figure 36 As shown, when calculating the concentration field, an average of 105 grid points were configured within the working area (z≤3m) (5 rows in the x direction, 7 rows in the y direction, and 3 rows in the z direction). Each grid point generates 2.85 mg / s of carbon monoxide (CO) as the tracking gas, for a total of m. p =300mg / s.

[0241] 2. Air supply: Q total =1536 cm² = 25.6 m 3 / s,

[0242] P=101325Pa, T=29℃, ρ=1.159kg / m 3 ,

[0243] rH = 55%

[0244] →m=Q total ×ρ=29.67kg / s,

[0245] 3. Expected average mass concentration f p Estimate:

[0246] Based on the formula for designing the overall parameters of the factory building in [Step A]

[0247] f p =m p / (m+m p )

[0248] →f CO =10.111ppm

[0249] Please also refer to Figure 1 , Figure 2 As shown, in this case, the windows are on the walls of the first side wall 12 and the second side wall 14, without partitions, and the horizontal position of the pipes is changed. The design parameters of the factory building 1 in this case are as follows: Figure 37 , Figure 38 As shown, the configurations of pipe 17 (a), (b), (c), and (d) are as follows: Figure 39 As shown. Based on the structure of the above embodiments, this application conducts simulation tests using the above parameters, and analyzes the calculation results using a computer program of Computational Fluid Dynamics (CFD). The statistical table of velocity, temperature, concentration, and pressure in the plant operation area is shown below. Figure 40 As shown.

[0250] Please also refer to Figure 41 , Figure 42As shown, it is another case with partitions 19. In which, there are several partitions 19 under the roof 11, and the partitions 19 are located at the same height as the pipes 17, and the partitions 19 are flat type ceiling with high thermal insulation coefficient, used to block the radiant heat emitted downward by the roof 11. The plant design parameter table is as shown in Figure 43 、 Figure 44 The pipe configuration modes (a), (b), (c), and (d) are the same as the previous case.

[0251] After analyzing the calculation results by the CFD computer program, in the cross section of the side elevation y = 3m, the velocity vector and streamline distribution diagram is as shown in Figure 45 ; the temperature field distribution diagram is as shown in Figure 46 ; and the concentration field distribution diagram is as shown in Figure 47 In the cross section of the end elevation x = 3m, the velocity vector and streamline distribution diagram is as shown in Figure 48 ; the temperature field distribution diagram is as shown in Figure 49 ; and the concentration field distribution diagram is as shown in Figure 50 In the cross section of the horizontal plane z = 1.8m, the velocity vector and streamline distribution diagram is as shown in Figure 51 ; the temperature field distribution diagram is as shown in Figure 52 ; and the concentration field distribution diagram is as shown in Figure 53 After detecting the results, the plant operating area velocity, temperature, concentration, and pressure statistical table of this case is as shown in Figures 55 to 58 In which, the arrow represents the velocity vector, and the black zone line along the tangent direction of the velocity vector represents the streamline; the color part represents the temperature, and the roof is specified as a temperature of 60℃, and the red color is the highest temperature (the inside temperature of the roof is specified as 60℃), followed by brown, yellow, light green, bright green, light blue to dark blue (the temperature of dark blue is the temperature of the atmosphere, specified as 29℃). As shown in ​ , it is two cases without partitions 19 and with partitions 19, and the comparison diagram of the average velocity, temperature, concentration, and pressure with the original plant shows that whether without partitions 19 or with partitions 19, the average velocity, temperature, concentration, and pressure are all better than those of the original plant.

[0252] In summary, according to the content disclosed above, the application can achieve the expected purpose, provide a plant ventilation and heat dissipation method that can achieve a positive pressure effect in the plant, make the pressure in the plant higher than the atmospheric pressure outside the plant, effectively block dust from floating into the plant, and reduce the temperature and even the concentration of pollutants in the plant, which has great industrial utilization value, and therefore an invention patent application is proposed according to the law.

Claims

1. A method of ventilating and cooling a factory building, characterized in that, The factory building comprises a roof and a plurality of side walls arranged successively below the roof, the roof and the side walls collectively framing an indoor space, the indoor space having at least one duct above to provide a plurality of downward air flows, and at least one window on at least one side wall for air exhaust; the factory building ventilation method comprises the following steps: A. The overall parameter design steps of the factory building, which are based on the total heat generation rate q of the factory building, set the allowable temperature rise Δ T , the total air requirement Q is theoretically estimated and adjusted total , the total area A of the at least one window win , the air outlet speed V of the at least one window win , the internal and external pressure difference ΔP of the indoor space win ; B. A duct height and air outlet geometry design step that selects and adjusts at least one duct installation minimum height h, air outlet length d j , air outlet width w j , air outlet spacing ratio s j / d j , air outlet number N j , air outlet average air speed u j ; C. The at least one pipe geometry design step, which is initially designed by using the basic principle of fluid mechanics, and then calculated by using the CFD computer program to design the at least one pipe geometry size, including the length L duct , the width W duct and the height H duct , wherein the pipe outlet velocity or flow uniformity adjustment method is the ratio method of the pipe cross-sectional area A duct and the total cross-sectional area A j,total of the outlet, which adjusts the at least one pipe geometry size width W duct and height H duct , flow Q duct , number N duct and outlet geometry size length d j , width w j , spacing s j , number N j to improve the static pressure distribution uniformity in the pipe, thereby improving the jet velocity uniformity of each outlet, so that the maximum wind speed or flow non-uniformity of the plurality of outlets reaches a satisfactory low value; D. A step of arranging the at least one duct in the factory building, wherein a CFD computer program is used to estimate and adjust the flow field, temperature field and concentration field in the factory building, and the height of the at least one duct and the height of the at least one window are adjusted so that the wind speed, temperature and concentration in the factory building reach the required values.

2. The method of claim 1, wherein, The plurality of side walls comprise a first side wall, a third side wall, a second side wall and a fourth side wall arranged successively, and the first side wall is parallel to the second side wall.

3. The method of claim 2, wherein, The first side wall and the second side wall respectively have the at least one window for air exhaust.

4. The method of claim 3, wherein, One end of the at least one duct is connected to the first side wall, and the other end of the at least one duct is connected to the second side wall, so that the at least one duct is perpendicular to the first side wall and the second side wall respectively.

5. The method of claim 1, wherein, At least one partition is further provided, and the at least one partition is arranged at the same height as the at least one duct.

6. The method of claim 5, wherein, The at least one partition is a flat plate with high thermal insulation coefficient, which blocks the radiant heat emitted downward from the roof.

7. The method of claim 1, wherein, The step A supplies filtered air from outside to the factory building to dilute the high temperature and pollutant concentration in the factory building, and makes the factory building in a positive pressure state.

8. The method of claim 1, wherein, Any duct has an upstream end and a downstream end, and the duct is divided into a plurality of tapered sections from the upstream end to the downstream end, and the plurality of sections respectively have at least one air outlet.

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