阅读说明：本技术 基于蒸汽管网模型的主动式疏水系统 (Active drainage system based on steam pipe network model ) 是由 赵琼 陈伦 刘成刚 谢金芳 王鹏飞 时伟 于 2020-12-17 设计创作，主要内容包括：本发明公开了基于蒸汽管网模型的主动式疏水系统,包括如下步骤：S1建立蒸汽热网的机理模型；S2设定疏水条件；S3根据热网运行的实时数据,使用步骤S1的模型计算各节点的蒸汽参数；S4根据疏水条件判定该管段是否需要疏水；S5判定需要疏水管段内的蒸汽流向,开启沿蒸汽流向方向上、距离需要疏水管段下游节点、最近的蒸汽直排管上的阀门进行疏水。本发明中根据蒸汽热网的机理模型判断网管内的蒸汽状态,并根据蒸汽的流向更加科学、合理的主动疏水,避免母管中堆积冷凝水,保证系统运行的稳定和安全。(The invention discloses an active drainage system based on a steam pipe network model, which comprises the following steps: s1, establishing a mechanism model of the steam heating network; s2 setting a hydrophobic condition; s3 calculating steam parameters of each node according to the real-time data of the operation of the heat supply network by using the model of the step S1; s4, judging whether the pipe section needs to be drained according to the drainage condition; s5, judging the steam flow direction in the pipe section needing water drainage, and opening a valve on the nearest steam straight-discharge pipe at a position away from the downstream node of the pipe section needing water drainage along the steam flow direction for water drainage. According to the invention, the steam state in the network pipe is judged according to the mechanism model of the steam heating network, and active drainage is more scientific and reasonable according to the flow direction of the steam, so that condensed water accumulation in the main pipe is avoided, and the stability and safety of system operation are ensured.)

1. Active drainage system based on steam pipe net model, its characterized in that: comprises that

S1, establishing a mechanism model of the steam heating network;

s2 setting a hydrophobic condition;

s3 calculating steam parameters of each node according to the real-time data of the operation of the heat supply network by using the model of the step S1;

s4, judging whether the pipe section between the adjacent nodes needs to be drained according to the drainage condition;

s5, judging the steam flow direction in the pipe section needing water drainage, and opening a valve on the nearest steam straight-discharge pipe at a position away from the downstream node of the pipe section needing water drainage along the steam flow direction for water drainage.

2. The active hydrophobic system based on a steam pipe network model of claim 1, wherein: the method for determining the steam flow direction in step S5 is as follows: acquiring the pressure at the adjacent node, and comparing the steam pressure at the adjacent node; the high pressure node is the upstream of the steam flowing in the pipe section, the low pressure node is the downstream of the steam flowing in the pipe section, and the flow direction of the steam in the pipe section is from the high pressure node to the low pressure node.

3. The active hydrophobic system based on a steam pipe network model of claim 1, wherein: the hydrophobic condition in step S2 is a steam flow rate threshold within a time threshold or a water depth threshold.

4. The active hydrophobic system based on steam pipe network model of claim 3, wherein: detecting a water depth threshold value through a liquid level meter; the liquid level meter is arranged on the steam pipe network main pipe and is arranged in front of the elbow and/or the valve.

5. The active hydrophobic system based on a steam pipe network model of claim 1, wherein: the steam parameters comprise the temperature of the steam, the pressure of the steam and the flow rate of the steam.

6. The active hydrophobic system based on a steam pipe network model of claim 1, wherein: the real-time data of the operation of the heat network comprises measured steam parameters at the heat source and measured steam parameters at the end user.

7. The active hydrophobic system based on a steam pipe network model of claim 1, wherein: the valve on the steam straight-discharge pipe is an electric valve.

8. The active hydrophobic system based on a steam pipe network model of claim 1, wherein: the mechanism model of the steam heat supply network comprises a hydraulic balance equation and a thermodynamic balance equation.

Technical Field

The invention relates to the field of heat supply drainage, in particular to an active drainage system based on a steam pipe network model.

Background

Steam conduit's female pipe can produce the comdenstion water in the pipeline at the in-process of carrying steam, and current steam drainage system is all through installing the trap passive drainage on the drainage branch pipe, and the branch pipe will be opened to the comdenstion water and drain, and if the comdenstion water in the female pipe has one section distance from the drainage branch pipe, and the steam local flow direction in the heat supply pipeline is chaotic, can cause the comdenstion water to flow to the drainage branch pipe along with steam smoothly, piles up in female pipe. The water accumulation in the mother pipe is caused, a water plug is formed when the water plug is mostly accumulated in the mother pipe and is pushed to advance by high-speed steam, and when the water plug is turned or greatly contracted in a short section, the water impact phenomenon is formed by impacting pipe walls, elbows, valves and other pipe accessories due to the large inertia of water, the water impact causes the vibration of the pipeline, the noise is generated, the pressure in the pipe is increased sharply, and the pipeline, the valves and equipment can be damaged in serious cases.

Disclosure of Invention

It is an object of the present invention to provide an active drainage system based on a steam pipe network model that solves one or more of the above mentioned technical problems.

In order to achieve the purpose, the technical scheme provided by the invention is as follows:

an active drainage system based on a steam pipe network model comprises

S1, establishing a mechanism model of the steam heating network;

s2 setting a hydrophobic condition;

s3 calculating steam parameters of each node according to the real-time data of the operation of the heat supply network by using the model of the step S1;

s4, judging whether the pipe section between the adjacent nodes needs to be drained according to the drainage condition;

s5, judging the steam flow direction in the pipe section needing water drainage, and opening a valve on the nearest steam straight-discharge pipe at a position away from the downstream node of the pipe section needing water drainage along the steam flow direction for water drainage.

Further: the method for determining the steam flow direction comprises the following steps: acquiring the pressure at the adjacent node, and comparing the steam pressure at the adjacent node; the high pressure node is the upstream of the steam flowing in the pipe section, the low pressure node is the downstream of the steam flowing in the pipe section, and the flow direction of the steam in the pipe section is from the high pressure node to the low pressure node.

Further: the hydrophobic condition in step S2 is a steam flow rate threshold within a time threshold or a water depth threshold.

Further: detecting a water depth threshold value through a liquid level meter; the liquid level meter is arranged on the steam pipe network main pipe and is arranged in front of the elbow and/or the valve.

Further: the steam state determination manner in step S4 is as follows: and (4) acquiring a steam pressure value in the pipeline through the model in the step S1, acquiring a steam saturation temperature value under the steam pressure value, and comparing the magnitude relation between the temperature value and the saturation temperature value to determine the steam state at the position.

Further: the steam parameters comprise the temperature of the steam, the pressure of the steam and the flow rate of the steam.

Further: the real-time data of the operation of the heat network comprises measured steam parameters at the heat source and measured steam parameters at the end user.

Further: the valve on the steam straight-discharge pipe is an electric valve.

Further: the mechanism model of the steam heat supply network comprises a hydraulic balance equation and a thermodynamic balance equation.

The invention has the technical effects that:

according to the invention, the steam state in the network pipe is judged according to the mechanism model of the steam heating network, and active drainage is more scientific and reasonable according to the flow direction of the steam, so that condensed water accumulation in the main pipe is avoided, and the stability and safety of system operation are ensured.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention.

In the drawings:

FIG. 1 is a schematic diagram of the overall flow structure of the present invention.

Fig. 2 is a schematic view of the opening valve of the present invention.

Detailed Description

The present invention will now be described in detail with reference to the drawings and specific embodiments, wherein the exemplary embodiments and descriptions are provided only for the purpose of illustrating the present invention and are not to be construed as unduly limiting the invention.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

As shown in FIG. 1, the active drainage system based on the steam pipe network model comprises

Firstly, establishing a mechanism model of a steam heating network;

the mechanism model of the steam heat supply network comprises a hydraulic balance equation and a thermodynamic balance equation. The method comprises the following specific steps: aiming at a steam pipe network containing l nodes, m pipe sections and n closed-loop circuits:

establishing a flow conservation equation at a node according to a kirchhoff first law:

LR＝Q (1)

l is a node pipeline incidence matrix;

r is the flow vector in each pipeline, R ═ R₁,R₂,…,R_m]^T；

Q is the vector of net mass flow at each node, Q ═ Q₁,Q₂,…,Q_l]Typically, the incoming node is taken to be positive and the outgoing node is taken to be negative.

From kirchhoff's second law, the pressure drop and temperature drop in a closed circuit are equal to zero:

BΔH＝0 (2)

BΔT＝0 (3)

b is a closed loop incidence matrix;

Δ H is a pipe segment pressure drop matrix of the closed loop, Δ H ═ Δ H₁,ΔH₂,...,ΔH_m]^T；

Δ T is a temperature drop matrix Δ T ═ Δ T of the closed loop₁,ΔT₂,...,ΔT_m]^T。

The pressure drop of the pipeline section can be obtained by a fluid mechanics related equation:

ΔH＝ε|R|R+ΔZ-P (4)

p is a pressure drop matrix of the pipe network water pump in the closed loop, and when the water pump does not exist, P is taken to be 0;

epsilon is the resistance correction coefficient of the pipeline segment;

and the delta Z is the difference value between the maximum value and the minimum value of the geographical elevation of the pipeline section.

The temperature drop of the pipeline section is related to the enthalpy drop and the heat dissipation capacity of the pipeline section, and the calculation formula of the enthalpy drop is as follows:

h_in,h_outfor pipe section to advanceAn outlet enthalpy value;

V_in,V_outthe flow rate of the inlet and the outlet of the pipe section;

Q_lheat loss for a section of pipeline;

q is the mass flow of the line section.

Heat loss per unit length of pipeline section Q₁The calculation formula of (A) is as follows:

Q_l＝KπD_o(T_m-T_a) (6)

in the above formula, the outside diameter D of the pipeline section_oAnd the heat transfer coefficient K are respectively expressed as formulas (7) and (8):

D_o＝D_m2δ_p+2δ_isu1+2δ_isu2 (7)

T_mis the steam temperature;

T_ais ambient temperature;

D_mis the inner diameter of the pipeline;

δ_pis the thickness of the tube wall;

δ_isu1,δ_isu2the thicknesses of the inner layer and the outer layer of the heat preservation layer are respectively set;

λ_p,λ_isu1,λ_isu2the heat conductivity coefficient of the pipe wall of the pipeline, the heat conductivity coefficient of the inner-layer heat-insulating layer and the heat conductivity coefficient of the outer-layer heat-insulating layer are respectively;

h_mheat transfer coefficient of convection heat exchange surface of steam and pipe wall;

h_athe heat transfer coefficient of the convection heat exchange surface between the outer heat insulation layer of the pipeline and the external environment;

h_rthe radiation heat transfer coefficient between the external heat-insulating layer of the pipeline and the external environment is adopted.

By combining the hydraulic balance equation and the thermal balance equation, the closed steam heat network model for multi-heat source combined heat supply can be solved.

Then setting a hydrophobic condition according to the use condition or expert experience;

here, there are two hydrophobic conditions, and active hydrophobic is performed as long as one of them is satisfied.

Wherein the first hydrophobic condition is: a steam flow rate threshold within a time threshold (e.g., T ≧ 30 s; V ≦ 1 m/s);

the second hydrophobic condition is: by installing a level meter on the steam pipe network main pipe, the level meter is arranged in front of the elbow and/or the valve (generally about 20 m), and whether the water is drained or not is judged according to the water depth threshold value at the position.

Next, calculating steam parameters of each node by using the model of the step S1 according to real-time data of the operation of the heat supply network; the steam parameters comprise the temperature of the steam, the pressure of the steam and the flow rate of the steam.

In this step, the entire model is input into the simulation software, and after acquiring real-time data (the real-time data of the heat network operation includes measured steam parameters at the heat source and measured steam parameters at the end user), corresponding values are input;

when the results in two adjacent nodes meet any one of the drainage conditions calculated by simulation software, an electric valve (capable of realizing remote and automatic active drainage) arranged on a straight-line side branch of the steam drainage valve is opened to carry out active drainage.

As shown in fig. 2, the open position of the trap is determined: firstly, judging the steam flow direction in a pipe section needing drainage, acquiring the pressure at an adjacent node, and comparing the steam pressure at the adjacent node; the high pressure node is the upstream of the steam flowing in the pipe section, the low pressure node is the downstream of the steam flowing in the pipe section, and the flow direction of the steam in the pipe section is from the high pressure node to the low pressure node. The low-pressure node is a downstream node, and an electric valve (on a straight-line side branch of the steam trap) closest to the downstream node is opened, and the valve framed in fig. 2 actively traps water.

The flow direction of steam is of great importance to dredging out accumulated water in the main pipe, the flow direction of steam in a local range in the pipeline is in a chaotic state, and when the flow direction of uncertain steam is opened to drain water, the wrong direction not only can lead to the fact that condensed water cannot be discharged, but also can lead to the loss of a large amount of steam, and the cost is increased.

The invention changes the traditional passive drainage mode, utilizes the hydraulic balance and thermodynamic balance equation to carry out simulation modeling on the heat supply pipeline, combines with real-time data to calculate the steam parameters of each node (any elbow, tee joint, valve, steam trap, opening and the like are all called as nodes), and can realize more reasonable and rapid active drainage by setting drainage conditions and according to the steam flow direction; the safety and the stability of the operation of the whole pipeline are effectively ensured.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.