A method for calculating energy loss of a gas flow system with a built-in cavity in a floor

Abstract

The present invention discloses a method for calculating the energy loss of a gas flow system of a built-in cavity in a floor, including: assuming the internal airflow flow pattern of a cavity formed by a single fully straight filling body, converting the cross section of the cavity corresponding to the incoming flow into a circular cross section with an equivalent diameter; respectively calculating the energy loss of the filling body cavity at the sudden expansion and the energy loss at the sudden contraction; calculating the resistance loss along the way inside the built-in concealed pipe and inside the filling body cavity; respectively calculating the energy loss of the cavity in the equal-section right-angle turn filling body and the energy loss of the cavity of the filling body at the smoke exhaust port of unequal cross-section; obtaining the total energy loss in a single series path; calculating the energy loss of each single series path at the aggregation pipe, and obtaining the energy loss of the aggregation pipe model as a whole. The present invention can accurately calculate the airflow energy loss of concealed pipe airflow flow systems of different scales and different design schemes, has a wide range of applications, and can conveniently and quickly solve the related problems of the airflow flow of the filling body cavity.

Description

Technical Field

[0001] The invention relates to the field of energy loss measurement, and in particular to an energy loss calculation method for a gas flow system with a built-in cavity in a floor slab. Background Art

[0002] Based on the flow of airflow in the cavity of the built-in filling body in the board, it means that the filling bodies in the floor are connected with the dark pipes of indefinite size, and the shapes of the dark pipes include but are not limited to round, rectangular, triangular, etc.; after the indoor gas enters the cavity in the floor from the exhaust port (or the outside), it is gradually discharged to the outside (exhaust port) through the dark pipes between the cavities to achieve the purpose of airflow. The consumption of the total energy of the airflow involved in the present invention depends on the number of filling bodies that the smoke passes through on the way from the exhaust port to the fan, and the resistance to the airflow includes the energy loss at the sudden contraction and expansion, the energy loss at the corner of the airflow, and the loss along the way due to the wear of the inner wall of the filling body and the inner wall of the dark pipe. The existing technology can only obtain the energy loss in the floor dark pipe by numerical simulation, but cannot be calculated by theoretical methods such as formulas. It is too dependent on numerical simulation software, and it is difficult to autonomously design the form of airflow flow in the cavity floor. In addition, numerical simulation technology can only provide macroscopic surface conclusions, which are difficult to compare with theoretical methods such as formulas for details. Therefore, the former cannot provide an effective method for optimizing the pipeline of floor airflow. Summary of the invention

[0003] The purpose of the present invention is to provide a method for calculating the energy loss of a gas flow system in a built-in cavity of a floor slab, so as to solve the problems existing in the above-mentioned prior art, to achieve accurate calculation of the airflow energy loss of concealed pipe airflow systems of different scales and different design schemes, and to a certain extent simplify the complexity of calculating the energy loss of the filling body cavity, so as to conveniently and quickly solve the related problems of the airflow flow in the filling body cavity.

[0004] To achieve the above object, the present invention provides the following solution: The present invention provides a method for calculating the energy loss of a gas flow system in a built-in cavity of a floor slab, comprising the following steps:

[0005] Setting the airflow pattern inside a single straight filling body, converting the cross section of the cavity corresponding to the incoming flow into a circular cross section with the same equivalent diameter;

[0006] Based on the circular cross section, respectively calculate the energy loss at the sudden expansion and the energy loss at the sudden contraction of the filling body cavity;

[0007] Calculate the energy loss along the built-in blind pipe and the cavity of the filling body;

[0008] Calculate the energy loss of the cavity in the filling body with equal cross-section and the energy loss of the cavity in the filling body at the smoke outlet with unequal cross-section respectively;

[0009] The total energy loss in a single series path is calculated based on the energy loss at the sudden expansion of the filling body cavity, the energy loss at the sudden contraction of the filling body cavity, the energy loss along the inside of the built-in concealed pipe and the inside of the filling body cavity, the energy loss of the cavity in the equal-section right-angle turn filling body, and the energy loss of the cavity of the filling body at the unequal-section smoke exhaust port;

[0010] The energy loss at the junction of each single series path and the collecting pipe and the resistance loss inside the collecting pipe are calculated according to the branch pipeline fluid energy loss formula to obtain the overall energy loss of the collecting pipe model.

[0011] Optionally, the calculation method of the energy loss at the sudden expansion of the filling body cavity is:

[0012]

[0013] Among them, h e The energy loss of the airflow in the cavity of the filling body due to the sudden expansion is is the local resistance coefficient of sudden expansion, A e2 is the area before the sudden expansion, A e1 is the area after sudden expansion, u e2 is the average velocity of the fluid before the sudden expansion, n is the number of blind tubes at the gas inflow end, It is the correction factor corresponding to different numbers of concealed pipes.

[0014] Optionally, the energy loss of the filling body cavity at the sudden contraction point is calculated as follows:

[0015]

[0016] Among them, h r is the energy loss at the constriction of the filling cavity, is the local resistance coefficient of the sudden contraction, A r2 is the area after the sudden contraction, A r1 is the area before the sudden contraction, u r1 is the average velocity of the fluid before the sudden contraction, and n is the number of dark tubes at the flue gas outflow end.

[0017] Optionally, the calculation method of the energy loss along the built-in concealed pipe is:

[0018]

[0019] Among them, h i is the energy loss along the built-in blind pipe, u i is the average flow velocity in the tube, L is the effective tube length, d is the diameter, λ i is the resistance coefficient along the way.

[0020] Optionally, the calculation method of the energy loss along the filling body cavity is:

[0021]

[0022] Among them, h o is the energy loss along the filling cavity, u o is the average flow velocity in the tube, L is the length of the gas flow direction of the filling cavity, d is the diameter of the equivalent circular tube, λ o is the resistance coefficient along the way.

[0023] Optionally, the energy loss of the airflow in the cavity of the equal-section right-angle turn filling body is calculated as follows:

[0024]

[0025] Among them, h k is the energy loss of the airflow in the cavity of the filling body with a right-angle turn of equal cross section, is the local resistance coefficient of the corner with equal areas of the entrance and exit, and u1 is the inlet wind speed.

[0026] Optionally, the calculation method of the airflow energy loss in the filling body cavity in the filling body at the smoke exhaust port of unequal cross-section is:

[0027]

[0028] Among them, h t is the energy loss of the airflow in the cavity of the filling body with unequal cross-section and right-angle turn, is the local resistance coefficient of the corner with unequal areas at the inlet and outlet, and u1 is the inlet wind speed.

[0029] Optionally, the total energy loss of the airflow in the series filling body is calculated as follows:

[0030]

[0031] Where: h single is the total energy loss of the airflow in the series filling body, is the energy loss of the sudden expansion of the filling cavity, n e is the number of sudden expansions of the filling cavity, is the energy loss of the filling cavity shrinkage, n r is the number of shrinkage occurrences, is the energy loss along the dark pipe, n i The number of times this loss occurred; is the energy loss along the cavity of the filling body, n o is the number of times energy loss occurs along the cavity of the filling body, is the energy loss caused by the rotation of the equal cross section, nk is the number of energy losses at the corner of the equal cross section, is the energy loss caused by simplifying the smoke outlet into unequal cross-section corners, n t is the total number of smoke exhaust ports in the model, h ex It is the energy loss caused by the working equipment.

[0032] Optionally, the energy loss at the junction of the concealed pipe and the collecting pipe is calculated as follows:

[0033]

[0034] in, The energy loss in the main pipe at the junction of the main and branch pipes, is the energy loss in the branch pipe at the junction of the main pipe and the branch pipe, Q1 and Q0 represent the flow rates of the branch pipe and main pipe respectively; A1 and A0 represent the area of ​​branch pipe and main pipe respectively; d1, d0 represent the diameters of the branch pipe and the main pipe respectively, θ represents the angle between the main pipe and the branch pipe, k s主 Used to calculate the energy loss of the displacement main tube, k s支 Used to calculate energy losses in branches.

[0035] Alternatively, the total energy loss of the summary tube model is calculated as:

[0036]

[0037] Among them, h all is the total energy loss, is the energy loss of the sudden expansion of the filling cavity, n e is the number of sudden expansions of the filling cavity, is the energy loss of the filling cavity shrinkage, n r is the number of shrinkage occurrences, is the energy loss along the dark pipe, n i The number of times this loss occurred; is the energy loss along the cavity of the filling body, n o is the number of times energy loss occurs along the cavity of the filling body, is the energy loss caused by the rotation of the equal cross section, n k is the number of energy losses at the corner of the equal cross section, is the energy loss caused by simplifying the smoke outlet into unequal cross-section corners, n t is the total number of smoke exhaust vents in the model, The energy loss in the main pipe at the junction of the main and branch pipes, is the energy loss in the branch pipe at the junction of the main pipe and the branch pipe, n sis the number of times the main branch energy loss occurs; h ex is the total energy loss caused by the working equipment.

[0038] The present invention discloses the following technical effects:

[0039] The present invention provides a method for calculating energy loss of a gas flow system with a built-in cavity in a floor slab, which can calculate the energy wear when the airflow passes through filling bodies of different numbers and arrangements, and provides a calculation method including total energy wear and pressure wear. It can also provide a general formula for total gas energy wear more accurately, and has good accuracy within a considerable range. It can also provide a solution reference for the selection of fan specifications and airflow path planning for concealed pipe airflow systems of different scales and design schemes. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0041] Figure 1 It is a schematic flow chart of a method for calculating energy loss of a gas flow system with a built-in cavity in a floor slab according to an embodiment of the present invention;

[0042] Figure 2 Schematic diagram of a circular diffuse jet (the jet is shown by an arrow) at a sudden expansion of a fully straight filling body in an embodiment of the present invention and a schematic diagram of the fully straight filling body, wherein Figure (a) is a circular diffuse jet at a sudden expansion of a fully straight filling body; Figure (b) is a fully straight filling body;

[0043] Figure 3 Schematic diagram of a cylindrical filling body cavity with equal cross-section equivalent after equivalent in an embodiment of the present invention, wherein Figure (a) is a rectangular cavity, and Figure (b) is a cylindrical filling body cavity with equal cross-section equivalent;

[0044] Figure 4 Schematic diagram of the actual contact range between the fluid and the wall surface in the cavity of the filling body and the gas flow in the embodiment of the present invention;

[0045] Figure 5 Schematic diagram of a rectangular filling body with equal cross-section and a schematic diagram of airflow in an embodiment of the present invention, wherein Figure (a) is a schematic diagram of a rectangular filling body with equal cross-section, and Figure (b) is a schematic diagram of airflow in a rectangular filling body with equal cross-section;

[0046] Figure 6Schematic diagram of a right-angle filling body with unequal cross-sections and a schematic diagram of airflow in an embodiment of the present invention, wherein Figure (a) is a schematic diagram of a right-angle filling body with unequal cross-sections, and Figure (b) is a schematic diagram of airflow in a right-angle filling body with unequal cross-sections;

[0047] Figure 7 A schematic diagram of a single series system and a schematic diagram of airflow in an embodiment of the present invention;

[0048] Figure 8 It is a schematic diagram of a floor with a cavity concealed pipe in the upper slab and a schematic diagram of airflow in an embodiment of the present invention;

[0049] Fig. 9 Schematic diagram of a smoke exhaust ventilation system for a multi-story building according to an embodiment of the present invention;

[0050] Fig.10 Schematic diagram of a multi-layer fluid domain in an embodiment of the present invention. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0053] The present invention provides a method for calculating the energy loss of a gas flow system in a built-in cavity of a floor slab. Figure 8-10The schematic diagram of the floor slab with built-in cavity concealed pipe airflow and the smoke exhaust ventilation system of a multi-story building is shown in the figure, wherein the many square structures composed of white closed square lines inside the floor slab are the filling body cavities inside the slab; the rectangular part used to connect the filling body cavities in the slab is the concealed pipe in the slab, that is, the concealed pipe in the floor slab, which is used to distinguish it from the exposed pipe used for traditional airflow; the small white square in some of the filling body cavities is the smoke exhaust port; when the airflow system is turned on, the flow pattern of the airflow presents the following characteristics: the smoke enters the filling body cavity inside the floor slab from the smoke exhaust port, reaches the next adjacent filling body cavity through the concealed pipe used to connect the filling body cavity, and then reaches the collection pipe on the far left, and is finally extracted by the fan connected to the collection, thereby achieving the purpose of airflow. The filling body cavity described in this embodiment is supported by an independent filling body during construction. The filling body can be made of a variety of materials and in a variety of shapes. The internal cavity is used to constitute the filling body cavity. The energy loss calculation involved in this embodiment includes three parts: the energy loss inside the filling body cavity formed by the filling body, the energy loss inside the blind pipe, and the energy loss inside the summary pipe.

[0054] like Figure 1 As shown, the airflow energy loss calculation method in this embodiment includes the following steps:

[0055] Step 1: Assuming the internal airflow pattern of a single straight filling body, convert the corresponding incoming flow section of the cavity surrounded by the filling body into a circular section with the same equivalent diameter; when the airflow enters the filling body cavity from the inlet blind pipe in a sudden expansion state (such as Figure 2 As shown in the figure, a rectangular cross-section cavity is used as an example here. The airflow diffuses from the boundary and interior of the inlet pipe to the cavity in a jet manner. Based on the basic characteristics of the jet, it is assumed that the jet diffusion pattern presents a ray with the center of the circle as the base point and points outward. The original cavity can be approximately equivalent to a cylindrical cavity with a circular cross-section equal to the equivalent diameter of the cross-section in the incoming flow direction.

[0056] Step 2: Calculate the energy loss at the sudden expansion and contraction of the filling cavity respectively.

[0057] In this embodiment, after the flow direction cross section of the filling body cavity is converted into an equivalent circular cross section with the same equivalent diameter according to step 1 (such as Figure 3 As shown, here a rectangular cross-section cavity is used as an example), and the energy loss formula for the sudden expansion and contraction of two cylinders of unequal cross-sectional areas is used for calculation.

[0058] Energy loss at the sudden expansion of the filling body h e The calculation expression is as shown in formula (1):

[0059]

[0060] Among them, h eis the energy loss of the airflow in the cavity formed by the filling body due to sudden expansion, is the local resistance coefficient of sudden expansion, A e2 is the area before the sudden expansion, A e1 is the area after sudden expansion, u e2 A is the average velocity of the fluid before the sudden expansion, and n is the number of dark tubes at the gas inlet end. Due to the different numbers of dark tubes, the degree of mutual interference of the gas flow in the airflow is different. The actual area after the sudden expansion is slightly smaller than A. e1 , so the formula is modified here, is the correction coefficient corresponding to different numbers of concealed pipes. When n is 1, 2, and 3, respectively, in this embodiment, the corresponding correction coefficients obtained by experiment are 1, 0.84, and 0.7, respectively. When the actual shape or size of the concealed pipe changes, the relevant parameters can be used to obtain the value of the correction coefficient through experiments.

[0061] Energy loss at the shrinkage point of the filling cavity h r , as shown in formula (2):

[0062]

[0063] Among them, h r To fill the energy loss of the constriction in the body cavity, is the local resistance coefficient of the sudden contraction, A r2 is the area after the sudden contraction, A r1 is the area before the sudden contraction, u r1 is the average velocity of the fluid before the sudden contraction, and n is the number of dark tubes at the flue gas outflow end.

[0064] Step 3: Calculate the energy loss along the inner tube and the cavity of the filling body respectively. The energy loss along the way is due to the viscosity of the smoke. The sticky behavior of the smoke when flowing along the wall is the energy loss caused by viscous friction.

[0065] In this embodiment, the calculation is performed according to the energy loss formula along the concealed pipe.

[0066] The energy loss expression along the built-in concealed pipe is h i , as shown in formula (3):

[0067]

[0068]

[0069] Among them, u i is the average flow velocity in the tube, L is the effective tube length, d is the diameter, Re is the Reynolds number, Δ is the absolute roughness of the tube wall, λ i is the resistance coefficient along the way, for λ i, it can be calculated using the method of calculating the resistance coefficient along the way in general fluid mechanics principles, or it can be calculated using the formula given above.

[0070] Due to the sudden expansion and contraction of the cross section, the airflow in the cavity of the filling body is not rubbed by the wall of the cavity of the filling body everywhere, but there are gaps at both ends, and the airflow and the wall are not in direct contact. The effective friction length between the airflow in the cavity of the filling body and the wall of the filling body is 0.7L (e.g. Figure 4 As shown in the figure, it is assumed here that the parameter L used to calculate the friction radial length is 0.7L. For other cases, this parameter can be obtained by experimentally measuring the effective friction length parameter based on the actual situation. The energy loss expression in the filling body cavity is obtained as h o , as shown in formula (4):

[0071]

[0072] u1S1=u o S o

[0073]

[0074] Among them, h o To fill the energy loss along the body, u1 represents the average velocity of the fluid in the built-in blind tube, S1, S o They represent the area of ​​the built-in blind pipe and the cross-sectional area of ​​the assumed circular cross-section filling cavity, u o is the average velocity of the airflow inside the cavity of the circular cross-section filling body, L is the effective length of the filling body cavity after conversion into a circular tube, and its value is equal to the length of the filling body cavity along the flow direction of the airflow, d is the diameter of the equivalent circular tube, Re is the Reynolds number, Δ is the absolute roughness of the tube wall, and λ o is the resistance coefficient along the way, for λ o The method for calculating the drag coefficient along the path in general fluid mechanics principles can be used for calculation, or the formula given above can be used for calculation. In this embodiment, the coefficient 0.7 is a correction coefficient corresponding to the calculation of the cavity of the filling body.

[0075] Step 4: Calculate the energy loss of the filling body cavity at the right-angle turn with equal cross-section according to the filling body energy loss formula at the right-angle turn, and calculate the airflow energy loss of the filling body cavity at the smoke exhaust port with unequal cross-section according to the modified differential formula, and combine the above energy losses to obtain the total energy loss in the series single path.

[0076] like Figure 5 As shown, when the inlet and outlet diameters of the right-angle filling body are equal, the energy loss expression is h k , as shown in formula (5):

[0077]

[0078]

[0079]

[0080] Among them, u1 is the inlet wind speed, θ is the actual turning angle. Since the turning angle is a right angle, it is preset to 90 here, d is the diameter of the inlet and outlet, and R is the turning radius, which depends on the average horizontal and vertical distances between the outlet and the inlet.

[0081] like Figure 6 As shown, when the diameters of the inlet and outlet of the right-angle filling body are not equal, the energy loss expression is h t , as shown in formula (6):

[0082]

[0083]

[0084]

[0085]

[0086] Where u1 is the inlet wind speed, θ is the actual turning angle, which is preset to 90°, d1 and d2 are the inlet and outlet diameters respectively. R is the turning radius, which depends on the average horizontal and vertical distances between the outlet and the inlet.

[0087] Step 5: Calculate the energy loss of each single series path (such as Figure 7 The energy loss of the airflow in the series filling body is obtained as h single , as shown in formula (7):

[0088]

[0089] in: represents the energy loss of the sudden expansion of the filling cavity, n e is the number of sudden expansions of the filling cavity, represents the energy loss of the filling cavity shrinkage, n r is the number of shrinkage occurrences, represents the energy loss along the dark pipe, n i Indicates the number of times this loss occurred; represents the energy loss along the cavity of the filling body, n o It indicates the number of times energy loss occurs along the filling body cavity. represents the energy loss caused by the rotation of the uniform cross section, nk represents the number of energy losses at the corner of the uniform cross section, represents the energy loss caused by simplifying the smoke outlet into unequal cross-section corners, n t represents the total number of smoke exhaust ports in the model, h ex It represents the total energy loss caused by working equipment. The total energy loss caused by working equipment includes but is not limited to the energy loss caused by smoke exhaust dampers, smoke exhaust fire dampers, ceiling windows, air conditioners and other equipment, and the system wear of the fan during operation. The energy loss is obtained by actual measurement or calculation.

[0090] Step 6: Calculate the energy loss in the main pipe and branch pipe at the intersection according to the fluid energy loss formula at the intersection of the branch pipe and the main pipe. It is obtained from the empirical formula of general fluid mechanics, as shown in formula (8):

[0091]

[0092]

[0093]

[0094] in, It represents the energy loss in the main pipe at the junction of the main pipe and the branch pipe. represents the energy loss in the branch pipe at the junction of the main pipe and the branch pipe, Q1 and Q0 represent the flow rates of the branch pipe and main pipe respectively; A1 and A0 represent the area of ​​branch pipe and main pipe respectively; d1, d0 represent the diameters of the branch pipe and the main pipe respectively, θ (0-90°) represents the angle between the main pipe and the branch pipe, k s主 Used to calculate the energy loss of the displacement main tube, k s支 Used to calculate energy losses in branches.

[0095] Step 7: In this embodiment, the total energy of the summary pipe model includes: the losses of multiple single paths, the energy loss at the summary pipe, the energy loss caused by friction in the summary pipe, and the system energy loss in the fan. According to the total energy loss formula of the summary pipe model, calculate the overall summary pipe model ( Figure 8 The total energy loss h all , as shown in formula (10):

[0096]

[0097] in, represents the energy loss of the sudden expansion of the filling cavity, n e is the number of sudden expansions of the filling cavity, represents the energy loss of the filling cavity shrinkage, n ris the number of shrinkage occurrences, represents the energy loss along the dark pipe, n i Indicates the number of times this loss occurred; represents the energy loss along the cavity of the filling body, n o It indicates the number of times energy loss occurs along the filling body cavity. represents the energy loss caused by the rotation of the uniform cross section, n k represents the number of energy losses at the corner of the uniform cross section, represents the energy loss caused by simplifying the smoke outlet into unequal cross-section corners, n t Represents the total number of smoke vents in the model. It represents the energy loss in the main pipe at the junction of the main pipe and the branch pipe. represents the energy loss in the branch pipe at the junction of the main pipe and the branch pipe, n s Indicates the number of times the main branch energy loss occurs, h ex It indicates the total energy loss caused by working equipment, including but not limited to the energy loss caused by smoke exhaust dampers, smoke exhaust fire dampers, ceiling windows, air conditioners and other equipment, and the system wear of fans during operation. The energy loss is obtained by actual measurement or calculation.

[0098] It is worth pointing out that, in this embodiment, smoke exhaust ventilation is used as an example for explanation and introduction, and the energy loss calculation method provided by the present invention is also applicable to various gas or liquid situations including fire extinguishing gas, cavity gas and heating, and is not limited to these situations.

[0099] Finally, it should be noted that the above-mentioned embodiments are only specific implementation methods of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them, especially the relevant specific parameters (specific parameters of different working conditions can be obtained through experiments) and functions (such as various cavity structure airflow design methods and iterative calculation techniques such as smoke exhaust ventilation, cavity, fire gas extinguishing, etc.), and the protection scope of the present invention is not limited to this. Although the present invention is described in detail with reference to the above-mentioned embodiments, ordinary technicians in this field should understand that any technician familiar with this technical field can still modify the technical solutions recorded in the above-mentioned embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. They should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for calculating energy loss of a gas flow system in a built-in cavity of a floor, characterized in that: The following steps are involved: Setting the airflow pattern inside a single straight filling body, converting the cross section of the cavity corresponding to the incoming flow into a circular cross section with the same equivalent diameter; Based on the circular cross section, the energy loss at the sudden expansion of the filling body cavity and the energy loss at the sudden contraction are calculated respectively. The calculation method of the energy loss at the sudden expansion of the filling body cavity is: Among them, h e The energy loss of the airflow in the cavity of the filling body due to the sudden expansion is is the local resistance coefficient of sudden expansion, A e2 is the area before the sudden expansion, A e1 is the area after sudden expansion, u e2 is the average velocity of the fluid before the sudden expansion, n is the number of dark tubes, is the correction factor corresponding to different numbers of concealed pipes; The calculation method of the energy loss of the filling body cavity at the sudden contraction is: Among them, h r is the energy loss at the constriction of the filling cavity, is the local resistance coefficient of the sudden contraction, A r2 is the area after the sudden contraction, A r1 is the area before the sudden contraction, u r1 is the average velocity of the fluid before the sudden contraction, n is the number of dark tubes; The energy loss along the built-in blind tube and the filling body cavity is calculated. The energy loss along the built-in blind tube is calculated as follows: Among them, h i is the energy loss along the built-in blind pipe, u i is the average flow velocity in the tube, L i is the effective tube length, d is the diameter of the equivalent tube, λ i is the resistance coefficient along the way; The calculation method of the energy loss along the filling body cavity is: Among them, h o is the energy loss along the filling cavity, u o is the average flow velocity in the tube, L o is the length of the gas flow direction of the filling cavity, d is the diameter of the equivalent circular tube, λ o is the resistance coefficient along the way; The energy loss of the cavity in the filling body with a right angle turn of equal cross section and the energy loss of the cavity in the filling body at the smoke exhaust port with unequal cross section are calculated respectively. The energy loss of the airflow in the cavity of the filling body with a right angle turn of equal cross section is calculated as follows: Among them, h k is the energy loss of the airflow in the cavity of the filling body with a right-angle turn of equal cross section, is the local resistance coefficient of the corner with equal area of ​​inlet and outlet, and u1 is the inlet wind speed; The calculation method of the airflow energy loss in the filling body cavity of the filling body at the smoke exhaust port of unequal cross-section is: Among them, h t is the energy loss of the airflow in the cavity of the filling body with unequal cross-section and right-angle turn, is the local resistance coefficient of the corner with unequal areas of inlet and outlet, and u1 is the inlet wind speed; The total energy loss in a single series path is calculated based on the energy loss at the sudden expansion of the filling body cavity, the energy loss at the sudden contraction of the filling body cavity, the energy loss along the inside of the built-in concealed pipe and the inside of the filling body cavity, the energy loss of the cavity in the equal-section right-angle turn filling body, and the energy loss of the cavity of the filling body at the unequal-section smoke exhaust port; The total energy loss in each of the single series paths and the energy loss at the junction of the central pipe are calculated according to the branch pipeline fluid energy loss formula to obtain the overall energy loss of the central pipe model. The energy loss at the junction of the central pipe is calculated as follows: in, The energy loss in the main pipe at the junction of the main and branch pipes, is the energy loss in the branch pipe at the junction of the main pipe and the branch pipe, k s主 Used to calculate the energy loss of the displacement main tube, k s支 Used to calculate the energy loss of branch pipes; The total energy loss calculation method of the overall summary pipe model is: Among them, h all is the total energy loss, is the energy loss of the sudden expansion of the filling cavity, n e is the number of sudden expansions of the filling cavity, is the energy loss of the filling cavity shrinkage, n r is the number of shrinkage occurrences, is the energy loss along the dark pipe, n i The number of times this loss occurred; is the energy loss along the cavity of the filling body, n o is the number of times energy loss occurs along the cavity of the filling body, is the energy loss caused by the rotation of the equal cross section, n k is the number of energy losses at the corner of the equal cross section, is the energy loss caused by simplifying the smoke outlet into unequal cross-section corners, n t is the total number of smoke exhaust vents in the model, The energy loss in the main pipe at the junction of the main and branch pipes, is the energy loss in the branch pipe at the junction of the main pipe and the branch pipe, n s is the number of times the main branch energy loss occurs; h ex is the total energy loss caused by the working equipment.

2. The energy loss calculation method for the built-in cavity gas flow system of the floor according to claim 1 is characterized in that: The total energy loss in the single series path is calculated as follows: Where: h single is the total energy loss of the airflow in the series filling body, is the energy loss of the sudden expansion of the filling cavity, n e is the number of sudden expansions of the filling cavity, is the energy loss of the filling cavity shrinkage, n r is the number of shrinkage occurrences, is the energy loss along the dark pipe, n i The number of times this loss occurred; is the energy loss along the cavity of the filling body, n o is the number of times energy loss occurs along the cavity of the filling body, is the energy loss caused by the rotation of the equal cross section, n k is the number of energy losses at the corner of the equal cross section, is the energy loss caused by simplifying the smoke outlet into unequal cross-section corners, n t is the total number of smoke exhaust ports in the model, h ex It is the energy loss caused by the working equipment.

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