﻿ 基于Modelica的船舶凝汽器动态特性分析
 舰船科学技术  2022, Vol. 44 Issue (23): 104-108    DOI: 10.3404/j.issn.1672-7649.2022.23.020 PDF

Dynamic characteristics analysis of marine condenser based on Modelica
ZENG Guo-qing, CHEN Guo-bing, LI Jun, CHEN Jun
College of Power Engineering, Naval University of Engineering, Wuhan 430033, China
Abstract: In order to realize the dynamic characteristic analysis of condenser, adopts modular modeling method, uses Modelica unified physical modeling language and Mworks simulation platform, and develops the model base of thermal system and establishes the condenser simulation model according to the working principle and energy and mass conservation equation of condensate and water supply system. By using the model, the dynamic characteristics of the condenser are analyzed under the condition of the turbine exhaust volume and the step change of circulating cooling water flow rate. The results show that the variation of the internal parameters of the condenser is consistent with the actual operation, which can provide reference for the optimization of the marine power system.
Key words: condenser     simulation     dynamic feature     Modelica
0 引　言

1 船舶凝给水仿真模型的建立 1.1 船舶凝给水系统的建模原理

 图 1 模块化建模原理 Fig. 1 Principle of modular modeling
1.2 凝给水系统

 图 2 凝给水系统工作原理简图 Fig. 2 Working principle diagram of condensate system
1.3 凝汽器数学模型

1.3.1 凝汽器壳侧数学模型

1）质量守恒定律

 ${G_i} = {G_{si}} + \sum {{G_{oi}}} - {G_{ci}} 。$ (1)

2）能量守恒定律

 ${Q_i} + {G_i}{h_i} = {G_{si}}{h_{si}} + \sum {({G_{oi}}{h_{oi}})} - {G_{ci}}{h_{ci}}，$ (2)

 ${Q_i} = {K_i}\Delta {t_i}A，$ (3)

 $p = f({h_i})。$ (4)

1.3.2 凝汽器管侧数学模型

1）热平衡方程[12]

 ${Q_i} = {K_i}\Delta {t_i}A = {G_c}{C_p}({T_{out}} - {T_{in}})。$ (5)

2）对数传热温差

 $\Delta {T_i} = \frac{{{T_{out}} - {T_{in}}}}{{\ln \dfrac{{{T_m} - {T_{in}}}}{{{T_m} - {T_{out}}}}}} 。$ (6)

1.4 除氧器模型

1）质量守恒方程

 $\sum {G_{in}} = {G_ {out }} ，$ (7)

2）能量守恒方程

 $\sum {G_{in}}{h_{in}} = {G_{out }} {h_s}，$ (8)

 $p = f({h_s})$ (9)

1.5 热力系统模型库

1.5.1 管道数学模型

1）质量守恒方程

 ${G_{in}} = {G_{out}} 。$ (10)

2）能量守恒方程

 $G_{in}h_{in}= {G_{out}}{h_{out}} 。$ (11)

3）动量守恒方程

 $\Delta p = p - {p_{out}} - \Delta H\rho g ，$ (12)
 $\Delta p = f\frac{l}{r}\frac{{\rho v\left| v \right|}}{2} 。$ (13)

1.5.2 边界模型

1.5.3 其他部件模型

2 仿真结果及分析

 图 3 凝给水系统模型 Fig. 3 Condensate system model

 图 4 凝汽器主要参数变化情况 Fig. 4 Changes of main parameters of condenser

2.1 汽轮机排汽量的影响

 图 5 凝汽器内部参数变化情况 Fig. 5 Changes of internal parameters of condenser
2.2 循环冷却水输入量的影响

$t$ =100 s时，在循环冷却水输入中分别加入冷却水量阶跃上升5%，10%，15%以及冷却水量阶跃下降5%，10%的阶跃信号，得到凝汽器入口蒸汽流量以及循环冷却水出口比焓对比如图6所示。仿真结果表明，当循环冷却水流量阶跃上升时，冷却水出口比焓与额定工况情况下相比明显下降；当循环冷却水流量阶跃下降时，冷却水出口比焓与额定工况情况下相比明显上升。这说明循环冷却水流量的增大会使得凝汽器内部换热能力增加，从而壳侧温度也会下降，汽轮机内部压力也将下降。

 图 6 凝汽器内部参数变化情况 Fig. 6 Changes of internal parameters of condenser

3 结　语

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