CN100511210C

CN100511210C - Hydrodynamic general design and checking method of boiler

Info

Publication number: CN100511210C
Application number: CNB2007100173797A
Authority: CN
Inventors: 车得福; 闫凯; 吉平; 唐勇; 莫春鸿; 王军; 吴梅; 殷晓川; 李毅; 胡国忠; 霍锁善
Original assignee: Xian Jiaotong University; Dongfang Boiler Group Co Ltd
Current assignee: Xian Jiaotong University; Dongfang Boiler Group Co Ltd
Priority date: 2007-02-06
Filing date: 2007-02-06
Publication date: 2009-07-08
Anticipated expiration: 2027-02-06
Also published as: CN101013416A

Abstract

The invention discloses a general design and verification method of boiler hydrodynamics. Firstly, initial values are assigned to the pressure and flow of each target component, and then pressure equations are listed for each target component of the direct flow system or natural circulation system of the boiler, and Form a pressure equation group, solve the pressure equation group to obtain a new set of pressure values, add these new pressure values to the pressure values of the inlet components of the system, and obtain the pressure values of each target component at a new level, and then update the upper level For the flow rate of each target component, a new pressure equation group is listed again for each target component after the updated flow rate, and so on, until the pressure and flow rate of each target component of the boiler's once-through system or natural circulation system meet the design accuracy. The present invention proposes a general model for boiler hydrodynamic calculation that can satisfy any pipeline layout, and the boiler hydrodynamic system is no longer divided according to series and parallel connections, making it possible to develop general boiler hydrodynamic calculation software.

Description

A Method for Universal Design and Check of Boiler Hydrodynamics

技术领域 technical field

本发明属于热能工程领域，涉及锅炉性能计算(设计和校核计算)方法，尤其是一种锅炉水动力通用设计和校核的方法。The invention belongs to the field of thermal energy engineering, and relates to a boiler performance calculation (design and check calculation) method, in particular to a boiler hydrodynamic universal design and check method.

背景技术 Background technique

锅炉的性能计算包括锅炉热力计算、水动力计算、强度计算以及其他锅炉辅助设备的计算等。在水动力计算中，最关键的是流量分配和压降的计算。因为分配特性直接影响到锅炉运行的安全性。手工进行锅炉水动力计算的工作量非常大。随着锅炉容量的增大和参数的提高，系统类型更加多样，水动力系统复杂程度急剧增加，手工计算耗时之大已不能满足需要。Boiler performance calculations include boiler thermal calculations, hydrodynamic calculations, strength calculations, and other boiler auxiliary equipment calculations. In hydrodynamic calculation, the most critical is the calculation of flow distribution and pressure drop. Because the distribution characteristics directly affect the safety of boiler operation. The workload of manual boiler hydrodynamic calculation is very large. With the increase of boiler capacity and the improvement of parameters, the system types become more diverse, and the complexity of the hydrodynamic system increases sharply. The time-consuming manual calculation can no longer meet the needs.

使用计算机进行计算的高效性有目共睹，采用计算机来代替水动力的手工计算已成为趋势。不少学者和单位都编写过水动力计算程序，但是现有的程序都是针对某一具体锅炉的。锅炉的水动力系统在编制前已经确定。当锅炉的水动力系统发生改变时，就必须重新编制计算程序。现有的水动力计算程序都无法做到通用，主要是因为无法对复杂的、布置灵活的锅炉水动力系统采用统一的形式进行描述。手工计算常采用绘制水动力特性曲线的方法。目前已经有文献公布了绘制水动力特性曲线的水动力计算机算法，如：The efficiency of calculations using computers is obvious to all, and it has become a trend to use computers to replace manual calculations of hydraulic power. Many scholars and units have compiled hydrodynamic calculation programs, but the existing programs are all aimed at a specific boiler. The hydrodynamic system of the boiler has been determined before compilation. When the hydrodynamic system of the boiler is changed, the calculation program must be reprogrammed. None of the existing hydrodynamic calculation programs can be generalized, mainly because it is impossible to use a unified form to describe the complex and flexible boiler hydrodynamic system. Manual calculation often adopts the method of drawing hydrodynamic characteristic curve. At present, some literatures have published the hydrodynamic computer algorithm for drawing the hydrodynamic characteristic curve, such as:

[1]田圃，陈听宽，毕勤成.多级串并联水冷壁系统水动力计算.锅炉技术.Vol 5，1996：6-12.[1] Tian Pu, Chen Tingkuan, Bi Qincheng. Hydrodynamic calculation of multi-stage series-parallel water wall system. Boiler Technology. Vol 5, 1996: 6-12.

[2]上海发电成套设备研究所.电站锅炉水动力计算方法.JB/Z 201-83.[2] Shanghai Institute of Complete Equipment for Power Generation. Calculation Method for Hydrodynamics of Power Plant Boilers. JB/Z 201-83.

如果采用绘制水动力特性曲线的方法，曲线的叠加与计算回归过程比较复杂和困难，曲线拟合存在一定的不准确性。绘制水动力特性曲线仍然是基于系统部件的串联关系和并联关系，而对于很多既非串联又非并联的特殊形式是无能为力的。当采用迭代法计算时，必须针对不同的系统类型采用不同的迭代方法，如果出现了新的系统类型，则必须采用新的迭代算法。因此，系统类型的多样性造成了计算机进行锅炉水动力计算非常复杂又不能实现通用。解决的办法之一就是寻找一种能描述复杂多样的水动力系统的统一形式。迄今为止，还没有相关的专利和其它类型的公开文献。If the method of drawing the hydrodynamic characteristic curve is adopted, the process of superimposing the curve and calculating the regression is more complicated and difficult, and the curve fitting has certain inaccuracy. Drawing the hydrodynamic characteristic curve is still based on the series relationship and parallel relationship of the system components, but it is helpless for many special forms that are neither series nor parallel. When the iterative method is used for calculation, different iterative methods must be used for different system types. If a new system type appears, a new iterative algorithm must be used. Therefore, the diversity of system types makes the calculation of boiler hydrodynamics by computer very complicated and cannot be used universally. One of the solutions is to find a unified form that can describe complex and diverse hydrodynamic systems. So far, there are no related patents and other types of publications.

发明内容 Contents of the invention

为了克服上述锅炉水动力计算中的不足，本发明从锅炉水动力系统和电路、管网的相似性出发，提出了一种锅炉水动力通用设计和校核的方法。该方法便于计算机处理，提高锅炉水动力计算的效率，缩短锅炉设计制造的周期，为锅炉水动力通用计算软件的开发打下基础。In order to overcome the shortcomings in the above-mentioned boiler hydrodynamic calculation, the present invention proposes a boiler hydrodynamic universal design and checking method based on the similarity of the boiler hydrodynamic system, circuit and pipe network. The method is convenient for computer processing, improves the efficiency of boiler hydrodynamic calculation, shortens the cycle of boiler design and manufacture, and lays a foundation for the development of boiler hydrodynamic general calculation software.

为了实现上述目的，本发明的技术方案是：In order to achieve the above object, technical scheme of the present invention is:

1.一种锅炉水动力通用设计和校核的方法，其特征在于，该方法采用部件压力法作为水动力计算的基本方法，步骤如下：1. A method for boiler hydrodynamic general design and checking, is characterized in that, the method adopts component pressure method as the basic method of hydrodynamic calculation, and the steps are as follows:

(1)对各个目标部件的压力和流量赋初值；(1) Assign initial values to the pressure and flow of each target component;

(2)对锅炉的直流系统或自然循环系统的各个目标部件列出压力方程，列方程按以下两步进行：(2) List the pressure equations for each target component of the once-through system or natural circulation system of the boiler, and the equations are listed in the following two steps:

1)部件的压力是指部件的入口压力，对锅炉水动力系统的每个部件进行编号，使得系统中每个部件都具有唯一编号；计算时通过调用编号可以查找到每个部件，其中混合集箱、分配集箱和汽水分离器为目标部件；1) The pressure of a component refers to the inlet pressure of the component. Each component of the boiler hydrodynamic system is numbered so that each component in the system has a unique number; each component can be found by calling the number during calculation, where the mixing set Tanks, distribution headers and steam separators are the target components;

2)为了减少方程组系数矩阵的大小，达到减少存储空间和提高计算速度的目的，只对各个目标部件分别列出压力方程，其中，考虑到方程组解的唯一性，除系统入口部件的压力方程以外，将其它压力方程组成压力方程组，以某个节点的流量平衡为基础，根据压力和流量的关系导出压力方程的表达式为：2) In order to reduce the size of the coefficient matrix of the equation system, achieve the purpose of reducing the storage space and improving the calculation speed, only the pressure equations are listed for each target component, where, considering the uniqueness of the solution of the equation system, except for the pressure of the system inlet component In addition to the equation, other pressure equations are composed of pressure equations, based on the flow balance of a certain node, the expression of the pressure equation is derived according to the relationship between pressure and flow:

${p p}_{00} {Σ Σ}_{I I = = 11}^{m m + + n no} \frac{11}{{R R}_{I I} {G G}_{I I}^{00}} - - {Σ Σ}_{I I = = 11}^{m m + + n no} \frac{{P P}_{I I}}{{R R}_{I I} {G G}_{} {I I}_{00}} = = {Σ Σ}_{I I = = 11}^{n no} \frac{{((\overset{&OverBar; &OverBar;}{ρ ρ} gh gh))}_{I I}}{{R R}_{Io Io} {G G}_{Io Io}^{00}} - - {Σ Σ}_{I I = = 11}^{m m} \frac{{((\overset{&OverBar; &OverBar;}{ρ ρ} gh gh))}_{I I}}{{R R}_{Ii II} {G G}_{Ii II}^{00}} - - {G G}_{s the s}$

其中：in:

p₀，p_I—部件压力，下标0表示对该部件列压力方程，下标I表示第I个部标部件，单位：Pa；p ₀ , p _I —component pressure, the subscript 0 indicates the pressure equation for the component, and the subscript I indicates the I-th subscript component, unit: Pa;

ρ—管子的平均密度，单位：kg/m³；ρ—the average density of the pipe, unit: kg/m ³ ;

m、n—表示部件0的m个入口支路，n个出口支路；m, n—indicates m entry branches and n exit branches of component 0;

上一个迭代层次部件I的某条入口或出口支路的流量，单位：kg/s；

The flow rate of a certain inlet or outlet branch of component I in the previous iteration level, unit: kg/s;

上一个迭代层次部件I的某条入口支路的流量，单位：kg/s；

The flow rate of a certain inlet branch of component I in the previous iteration level, unit: kg/s;

上一个迭代层次部件I的某条出口支路的流量，单位：kg/s；

The flow rate of a certain outlet branch of component I in the previous iteration level, unit: kg/s;

G_s—从部件0中流出的流量，单位：kg/s；G _s — flow out of component 0, unit: kg/s;

R_I、R_Io、R_Ii—表示和的类电阻系数，R的值由下式确定：R _I , R _Io , R _Ii — means and The class resistivity, the value of R is determined by the following formula:

对于单相流体For a single phase fluid

$R R = = \frac{11}{{A A}^{22}} [[((λ λ \frac{l l}{{22 d d}_{n no}} + + \frac{ζ ζ}{22})) \overset{&OverBar; &OverBar;}{v v} + + | | {v v}_{22} - - {v v}_{11} | |]]$

对于两相流体For a two-phase fluid

$R R = = \frac{11}{{A A}^{22}} {{((φλ φλ \frac{l l}{22 ρ ρ' '} + + \frac{ζ ζ}{22 ρ ρ' '})) [[11 + + \overset{&OverBar; &OverBar;}{x x} ((\frac{ρ ρ' '}{ρ ρ' '' '} - - 11))]] + + | | {x x}_{c c} - - {x x}_{j j} | | (({v v}^{' '' '} - - v v' '))}}$

式中：In the formula:

A—管子截面积，单位：m²；A—the cross-sectional area of the pipe, unit: m ² ;

d_n—管子内径，单位：m；d _n — inner diameter of the pipe, unit: m;

l—管子长度，单位：m；l—pipe length, unit: m;

λ—摩擦阻力系数；λ—frictional resistance coefficient;

φ—摩擦阻力压力降校正系数；φ—Friction resistance pressure drop correction coefficient;

ζ—局部阻力系数；ζ—local resistance coefficient;

ρ′、ρ″—饱和水密度，饱和蒸汽密度，单位：kg/m³；ρ′, ρ″—saturated water density, saturated steam density, unit: kg/m ³ ;

v′、v″、v₁、v₂、v—分别为饱和水比容、饱和蒸汽比容、管子入口比容、管子出口比容、管子平均比容，单位：m³/kg；v′, v″, v ₁ , v ₂ , v—are saturated water specific volume, saturated steam specific volume, pipe inlet specific volume, pipe outlet specific volume, and pipe average specific volume, unit: m ³ /kg;

x_j、x_c、x—分别为管子入口干度、管子出口干度、管子平均干度。x _j , x _c , x—are pipe inlet dryness, pipe outlet dryness, and pipe average dryness, respectively.

(3)组成压力方程组，求解该压力方程组得到一组新的压力值，将这些新的压力值加上系统入口部件的压力值，得到新一层次各个部件的压力值；(3) form a group of pressure equations, solve the group of pressure equations to obtain a group of new pressure values, add these new pressure values to the pressure values of the system inlet components, and obtain the pressure values of each component at a new level;

(4)更新上一层次的各个目标部件的流量，对更新流量后的该各个目标部件再次列出新的压力方程组；(4) Update the flow rate of each target component at the upper level, and list new pressure equations again for each target component after the updated flow rate;

(5)重复步骤(2)至步骤(4)，直到锅炉的直流系统或自然循环系统的各个目标部件的压力和流量满足设计精度为止。(5) Repeat steps (2) to (4) until the pressure and flow of each target component of the boiler's once-through system or natural circulation system meet the design accuracy.

2.如权利要求1所述的方法，其特征在于，步骤如下：2. The method according to claim 1, characterized in that the steps are as follows:

(1)断开所有锅筒和进入锅筒的部件的连接关系，在所有进入锅筒的部件的出口处添加一个虚拟集箱，使得所有进入锅筒的部件的出口是该虚拟集箱；(1) Disconnect the connection relationship between all drums and parts entering the drum, and add a virtual header at the outlet of all parts entering the drum, so that the outlets of all parts entering the drum are the virtual header;

(2)假设自然循环系统的循环倍率和锅筒中水的欠焓：(2) Assuming the circulation rate of the natural circulation system and the underenthalpy of the water in the drum:

(3)按照权利要求1所述的方法进行计算；(3) calculate according to the method described in claim 1;

(4)计算自然循环系统的循环倍率和锅筒中水的欠焓，并和假设值比较，并且比较系统入口和出口的压力是否相等；如果满足精度，则停止计算；如果不满足精度，更新循环倍率、锅筒中水的欠焓和入口压力，计算从步骤三开始重新计算，直到满足设计精度为止。(4) Calculate the circulation rate of the natural circulation system and the underenthalpy of the water in the drum, and compare it with the assumed value, and compare whether the pressure at the inlet and outlet of the system is equal; if the accuracy is satisfied, the calculation is stopped; if the accuracy is not satisfied, the cycle is updated Multiplier, underenthalpy of water in the drum and inlet pressure, the calculation is recalculated from step 3 until the design accuracy is met.

本发明的方法提出了能满足任何管路布置方式的锅炉水动力计算的通用模型，而锅炉水动力系统不再根据串联和并联进行划分。采用该方法不仅可以进行只存在串联和并联关系的锅炉系统的水动力计算，而且可以进行存在既非串联又非并联的特殊管路的锅炉系统的水动力计算。该方法使锅炉水动力系统的划分简单明了，大大缩短了使用计算机进行锅炉水动力计算的计算时间，使得开发通用的锅炉水动力计算软件成为可能。The method of the invention proposes a general model for boiler hydrodynamic calculation that can satisfy any pipeline arrangement, and the boiler hydrodynamic system is no longer divided according to series connection and parallel connection. This method can be used not only for the hydrodynamic calculation of the boiler system with only series and parallel connections, but also for the hydrodynamic calculation of the boiler system with special pipelines that are neither in series nor in parallel. This method makes the division of the boiler hydrodynamic system simple and clear, greatly shortens the calculation time of the boiler hydrodynamic calculation using a computer, and makes it possible to develop a general boiler hydrodynamic calculation software.

附图说明 Description of drawings

图1是本发明方法的基本模型图。Fig. 1 is a basic model diagram of the method of the present invention.

图2是本发明方法的算法流程图。Fig. 2 is an algorithm flow chart of the method of the present invention.

图3是一个真实锅炉水动力系统的示意图，其中实心圆圈表示目标部件，空心圆圈表示非目标部件，箭头表示工质流动方向。Figure 3 is a schematic diagram of a real boiler hydrodynamic system, where solid circles represent target components, hollow circles represent non-target components, and arrows represent the flow direction of working fluid.

为了更清楚地理解本发明，以下结合附图和发明人给出的具体实例对本发明作进一步的详细描述。In order to understand the present invention more clearly, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific examples given by the inventor.

具体实施方式 Detailed ways

依照本发明的技术方案，锅炉水动力通用设计和校核的方法，首先列出压力方程并求解，然后对直流系统和自然循环系统分别做一些特殊处理。According to the technical solution of the present invention, the general design and verification method of boiler hydrodynamics first lists and solves the pressure equation, and then performs some special treatment on the direct flow system and the natural circulation system respectively.

压力方程的列出按以下步骤进行：The listing of the pressure equation proceeds as follows:

1)部件的压力是指部件的入口压力。对锅炉水动力系统的每个部件进行编号，使得系统中每个部件都具有唯一编号。计算时通过调用编号可以查找到每个部件。其中混合集箱、分配集箱和汽水分离器为目标部件。1) The pressure of the part refers to the inlet pressure of the part. Number each component of the boiler hydrodynamic system so that each component in the system has a unique number. Each part can be found by calling the number during calculation. Among them, mixing header, distribution header and steam separator are the target components.

2)为了减少方程组系数矩阵的大小，达到减少存储空间和提高计算速度的目的，只对各个目标部件分别列出压力方程，其中，考虑到方程组解的唯一性，除系统入口部件的压力方程以外，将其它压力方程组成压力方程组，以某个节点的流量平衡为基础，根据压力和流量的关系可以导出压力方程的表达式：2) In order to reduce the size of the coefficient matrix of the equation system, achieve the purpose of reducing the storage space and improving the calculation speed, only the pressure equations are listed for each target component, where, considering the uniqueness of the solution of the equation system, except for the pressure of the system inlet component In addition to the equation, other pressure equations are composed of pressure equations, based on the flow balance of a certain node, the expression of the pressure equation can be derived according to the relationship between pressure and flow:

${p p}_{00} {Σ Σ}_{I I = = 11}^{m m + + n no} \frac{11}{{R R}_{I I} {G G}_{I I}^{00}} - - {Σ Σ}_{I I = = 11}^{m m + + n no} \frac{{P P}_{I I}}{{R R}_{I I} {G G}_{I I}^{00}} = = {Σ Σ}_{I I = = 11}^{n no} \frac{{((\overset{&OverBar; &OverBar;}{ρ ρ} gh gh))}_{I I}}{{R R}_{Io Io} {G G}_{Io Io}^{00}} - - {Σ Σ}_{I I = = 11}^{m m} \frac{{((\overset{&OverBar; &OverBar;}{ρ ρ} gh gh))}_{I I}}{{R R}_{Ii II} {G G}_{Ii II}^{00}} - - {G G}_{S S}$

其中：in:

p₀，p_I：部件压力，下标0表示对该部件列压力方程，下标I表示第I个部标部件，单位：Pa；p ₀ , p _I : component pressure, the subscript 0 indicates the pressure equation for the component, and the subscript I indicates the I-th subscript component, unit: Pa;

上一个迭代层次部件I的某条入口支路的流量，单位：kg/s；

上一个迭代层次部件I的某条出口支路的流量，单位：kg/s；

R_I、R_Io、R_Ii—表示

和

的类电阻系数，R的值由下式确定：R _I , R _Io , R _Ii — means

and

The class resistivity, the value of R is determined by the following formula:

对于单相流体For a single phase fluid

对于两相流体For a two-phase fluid

其中：in:

A—管子截面积，m²；A—the cross-sectional area of the pipe, m ² ;

d_n—管子内径，m；d _n — inner diameter of the pipe, m;

l—管子长度，m；l—pipe length, m;

λ—摩擦阻力系数；λ—frictional resistance coefficient;

ζ—局部阻力系数；ζ—local resistance coefficient;

ρ′、ρ″—饱和水密度，饱和蒸汽密度，kg/m³；ρ′, ρ″—saturated water density, saturated steam density, kg/m ³ ;

v′、v″、v₁、v₂、v—饱和水，饱和蒸汽，管子入口，管子出口，管子平均比容，m³/kg；v′, v″, v ₁ , v ₂ , v—saturated water, saturated steam, pipe inlet, pipe outlet, average specific volume of pipe, m ³ /kg;

x_j、x_c、x—管子入口，管子出口，管子平均干度。x _j , x _c , x—pipe inlet, pipe outlet, and average dryness of the pipe.

求解上述压力方程组，得到新的压力值。将这些值同时加上系统入口部件的压力值，得到新一层次各个部件的压力值。Solve the above pressure equations to get the new pressure value. Add these values to the pressure values of the system inlet components at the same time to obtain the pressure values of each component at the new level.

根据下式更新每个部件的流量Update the flow rate of each component according to

$G G = = \sqrt{\frac{U u}{R R}}$

其中：in:

U—某部件新一层次的，摩擦阻力和局部阻力值之和，Pa；U—the sum of frictional resistance and local resistance value of a new level of a component, Pa;

R—某支路新一层次的类电阻系数，Pa·s²/m²；R—the similar resistance coefficient of a new level of a branch, Pa·s ² /m ² ;

用上述新方法计算直流系统时，按以下步骤进行：When using the above new method to calculate the DC system, follow the steps below:

给部件的压力和流量值赋初值，运用上述方法迭代计算，直到部件的压力和流量满足一定精度为止。Assign initial values to the pressure and flow values of the components, and use the above method to iteratively calculate until the pressure and flow of the components meet a certain accuracy.

用上述方法计算自然循环系统时，按以下步骤进行：When using the above method to calculate the natural circulation system, proceed as follows:

1)断开所有锅筒和进入锅筒的部件的连接关系，再所有进入锅筒的部件的出口处添加一个虚拟集箱，使得所有进入锅筒的部件的出口是该虚拟集箱。1) Disconnect all the connections between the drum and the parts entering the drum, and add a virtual header at the outlet of all the parts entering the drum, so that the outlets of all the parts entering the drum are the virtual header.

2)假设自然循环系统的循环倍数和锅筒中水的欠焓，给部件的压力和流量赋初值。2) Assuming the circulation multiple of the natural circulation system and the underenthalpy of the water in the drum, assign initial values to the pressure and flow of the components.

3)运用上述方法迭代计算，直到部件的压力和流量满足设计精度为止。3) Use the above method to iteratively calculate until the pressure and flow of the components meet the design accuracy.

4)计算自然循环系统的循环倍率和锅筒中水的欠焓，并和假设值比较，并且比较系统入口和出口的压力是否相等；如果系统入口和出口的压力相等，循环倍率、欠含以及各个部件的压力、流量满足精度，则停止计算；如果系统入口和出口的压力不相等，循环倍率、欠含以及各个部件的压力、流量不满足精度，则更新循环倍率、锅筒中水的欠焓和入口压力，计算从步骤3开始重新计算，直到满足设计精度为止。4) Calculate the circulation rate of the natural circulation system and the underenthalpy of the water in the drum, and compare it with the assumed value, and compare whether the pressure at the inlet and outlet of the system is equal; If the pressure and flow rate of the components meet the accuracy, stop the calculation; if the pressure at the inlet and outlet of the system is not equal, the cycle rate, under-content, and the pressure and flow rate of each component do not meet the accuracy, then update the cycle rate, the under-enthalpy of the water in the drum and Inlet pressure, the calculation is recalculated from step 3 until the design accuracy is met.

参见图3，该图是一个锅炉真实水动力系统的示意图。该锅炉系统是一个直流系统。图中实心圆圈表示目标部件，空心圆圈表示除目标部件以外的其它部件，箭头表示工质流动方向。系统中共有5个目标部件，编号为0～4。根据所述方法的步骤，对编号为1～4的目标部件分别列出压力方程。以编号为2的目标部件为例，该部件有1个入口支路和2个出口支路。分别计算出这些支路对应的RG⁰和ρgh，再计算出该部件压力方程中的各项系数，最后列出该部件的压力方程。将编号为1～4的目标部件分别对应的压力方程组成压力方程组，求解即可得到各个目标部件对应的新的压力值，将这些值同时加上系统入口部件的压力值，得到新一层次各个部件的压力值。用这些新的压力值更新各个进出口支路的流量，得到新一层次的各个部件的流量值。比较新旧层次的压力和流量值，如果满足精度要求，则停止计算，所得压力和流量就是所求结果；如果不满足精度要求，则用新的压力和流量列出新的压力方程，按照前面介绍的步骤重复计算，直到满足精度为止。See Figure 3, which is a schematic diagram of a real hydrodynamic system of a boiler. The boiler system is a once through system. The solid circles in the figure represent the target components, the hollow circles represent other components except the target components, and the arrows represent the flow direction of the working fluid. There are 5 target components in the system, numbered 0-4. According to the steps of the method, the pressure equations are respectively listed for the target components numbered 1-4. Take the target part numbered 2 as an example, this part has 1 entry branch and 2 exit branches. Calculate the RG ⁰ and ρgh corresponding to these branches respectively, and then calculate the coefficients in the pressure equation of this part, and finally list the pressure equation of this part. The pressure equations corresponding to the target components numbered 1 to 4 are composed of pressure equations, and the new pressure values corresponding to each target component can be obtained by solving them, and these values are added to the pressure values of the system inlet components at the same time to obtain a new level The pressure value of each component. Use these new pressure values to update the flow of each inlet and outlet branch, and obtain the flow values of each component at a new level. Compare the pressure and flow values of the new and old levels, if the accuracy requirements are met, stop the calculation, and the obtained pressure and flow are the desired results; if the accuracy requirements are not met, use the new pressure and flow to list a new pressure equation, as described above The steps are repeated until the precision is satisfied.

Claims

1. the method for boiler hydrodynamics universal design and check is characterized in that, this method adopts the basic skills of parts pressure application as Calculation of Hydrodynamic, and step is as follows:

(1) to the pressure and the flow initialize of each target component;

(2) straight-flow system of boiler or each target component of natural cycle system are listed pressure equation, establish an equation and undertaken by following two steps:

1) pressure of parts is meant the inlet pressure of parts, and each parts of boiler hydrodynamics system are numbered, and makes that each parts all has unique number in the system; Can find each parts by call number during calculating, wherein mixing header, allocation set case and steam-water separator are target component;

2) in order to reduce the size of system of equations matrix of coefficients, reach the purpose that reduces storage space and improve computing velocity, only each target component is listed pressure equation respectively, wherein, consider the system of equations uniqueness of solution, except that the pressure equation of system entry parts, with other pressure equation decomposition pressure system of equations, based on the flow equilibrium of certain node, the expression formula that derives pressure equation according to the relation of pressure and flow is:

p_{0} Σ_{I = 1}^{m + n} \frac{1}{R_{I} G_{I}^{0}} - Σ_{I = 1}^{m + n} \frac{p_{I}}{R_{I} G_{I}^{0}} = Σ_{I = 1}^{n} \frac{{(\overset{&OverBar;}{ρ} gh)}_{I}}{R_{Io} G_{Io}^{0}} - Σ_{I = 1}^{m} \frac{{(\overset{&OverBar;}{ρ} gh)}_{I}}{R_{Ii} G_{Ii}^{0}} - G_{s}

Wherein:

p ₀, p ₁-parts pressure, subscript 0 expression is to this parts row pressure equation, and subscript I represents I standard laid down by the ministries or commissions of the Central Government parts, unit: Pa;

The average density of ρ-pipe, unit: kg/m ³

M inlet branch road of m, n-expression parts 0, n outlet branch road;

Certain the bar inlet an of-last iteration level parts I or the flow of outlet branch road, unit: kg/s;

The flow of certain bar inlet branch road an of-last iteration level parts I, unit: kg/s;

The flow of certain bar outlet branch road an of-last iteration level parts I, unit: kg/s;

G _sThe flow of-outflow from parts 0, unit: kg/s;

R _I, R _Io, R _Ii-expression

With

The quasi-resistance coefficient, the value of R is determined by following formula:

For monophasic fluid

R = \frac{1}{A^{2}} [(λ \frac{l}{2 d_{n}} + \frac{ζ}{2}) \overset{&OverBar;}{v} + | v_{2} - v_{1} |]

For two-phase fluid

R = \frac{1}{A^{2}} {(φλ \frac{l}{2 ρ'} + \frac{ζ}{2 ρ'}) [1 + \overset{&OverBar;}{x} (\frac{ρ'}{ρ''} - 1)] + | x_{c} - x_{j} | (v'' - v')}

In the formula:

A-pipe section is long-pending, unit: m ²

d _n-ips, unit: m;

L-tube length, unit: m;

λ-coefficient of frictional resistance;

Correction coefficient falls in φ-frictional resistance pressure;

ζ-coefficient of shock resistance;

ρ ', ρ "-saturation water density, saturated vapor density, unit: kg/m ³

V ', v ", v ₁, v ₂, v-be respectively saturation water specific volume, saturated vapour specific volume, pipe inlet specific volume, pipe outlet specific volume, the average specific volume of pipe, unit: m ³/ kg;

x _j, x _c, x-be respectively pipe inlet mass dryness fraction, pipe outlet mass dryness fraction, the average mass dryness fraction of pipe;

(3) decomposition pressure system of equations is found the solution this pressure equation group and is obtained one group of new force value, and the force value that these are new adds the force value of system entry parts, obtains the force value of new each parts of level;

(4) upgrade the flow of each target component of last layer time, this each target component that upgrades behind the flow is listed new pressure equation group once more;

(5) repeating step (2) is to step (4), till the pressure of each target component of the straight-flow system of boiler or natural cycle system and flow satisfy design accuracy.

2. the method for claim 1 is characterized in that, step is as follows:

(1) annexation that disconnects all drums and enter the parts of drum is added a virtual collection case in all exits that enter the parts of drum, and the outlet that makes all enter the parts of drum is this virtual collection case;

(2) suppose the enthalpy of owing of water in the circulating ratio of natural cycle system and the drum;

(3) calculate in accordance with the method for claim 1;

(4) calculate the enthalpy of owing of water in the circulating ratio of natural cycle system and the drum, and and default relatively, and whether the pressure of comparison system entrance and exit equates; If satisfy precision, then stop to calculate; If do not satisfy precision, that upgrades water in circulating ratio, the drum owes enthalpy and inlet pressure, calculates to begin to recomputate from step (3), till satisfying design accuracy.