﻿ 多参数迭代的船用二回路系统热平衡计算方法
 舰船科学技术  2018, Vol. 40 Issue (6): 79-83 PDF

Heat balance computing method of marine secondary circuit system by using multi-parameter iteration
CUI Jia-lin, YANG Zi-chun, ZHANG Lei
Institute of High Temperature Structural Composite Materials for Naval Ship, School of Power Engineering, Navy University of Engineering, Wuhan 430033, China
Abstract: According to types of equipment and operation characteristics of Marine nuclear power plant, the method of steam consumption computing of main secondary circuit equipment is given. A multi-parameter iteration heat balance computing model is established on the basis of considering practical features such as multi-equipment, multi-mode and strong coupling of secondary circuit. The known parameters are used to verify the established heat balance model and the computing precision. The steam and water flow rate and the matching feature of peculiar equipment of nuclear power plant under three typical operating conditions are analyzed, and the efficiency of power plant under different operating conditions is achieved. Through the research result of secondary circuit, technology references are provided for the study of variable operation and design optimization.
Key words: nuclear power     secondary circuit     heat balance     multi-parameter iterative method
0 引　言

1 二回路主要设备耗汽量计算

1）由于主汽轮机高压缸排汽压力与低压缸进汽压力差别较小，在计算中忽略沿程阻力损失，认为二者相等。

2）视冷凝器中各处工作压力分布均匀，进而由冷凝器工作压力对应的饱和温度减去过冷度得出汽水温度和焓值。

3）正车速关阀后少部分蒸汽进入除主汽轮机组外的其他设备做功，假设这部分蒸汽的参数始终等于进入主汽轮机组的蒸汽参数[14]

 $\begin{split}{P_{sg}} =& {G_s} \cdot ({h_{sg\_o\_s}} - {h_{sg\_o\_w}}) + \\&{G_s} \cdot (1 + {u_{pw}}) \cdot ({h_{sg\_o\_w}} - {h_{fw}})\text{，}\end{split}$ (1)

 $\begin{split}{G_s} =& {P_{sg}}/(({h_{sg\_o\_s}} - {h_{sg\_o\_w}})+ \\& (1 + {u_{pw}}) \cdot ({h_{sg\_o\_w}} - {h_{fw}})) \text{。}\end{split}$ (2)

 ${G_{ht}} - {G_{lt}} = {G_{sp\_w}}\text{。}$ (3)

 ${G_{ht}} \cdot {H_{ht}} + {G_{lt}} \cdot {H_{lt}} = {N_e}/(ef{f_{eff\_m}} \cdot ef{f_{eff\_g}})\text{，}$ (4)
 ${h_{ht\_o}} = ({h_{ht\_o\_s}} \cdot {G_{lt}} + {h_{ht\_o\_w}} \cdot {G_{sp\_w}})/{G_{ht}}\text{。}$ (5)

 ${N_{eg}} = {G_{eg}} \cdot {H_{eg}} \cdot (ef{f_{eg\_m}} \cdot ef{f_{eg\_g}} \cdot ef{f_{eg}})\text{。}$ (6)

 ${G_{eg}} = {N_{eg}}/(ef{f_{eg\_m}} \cdot ef{f_{eg\_g}} \cdot ef{f_{eg}})/{H_{eg}}\text{。}$ (7)

 ${N_{fwp}} \cdot ef{f_{fw\_p}} = {G_{fw}} \cdot g \cdot {H_{fw\_p}}\text{。}$ (8)

 ${N_{fwp}} = {G_{s\_fwp}} \cdot {H_{fw}} \cdot ef{f_{fw\_m}}\text{。}$ (9)

 ${G_{eje\_1}} = {u_{eje\_1}} \cdot ({G_{eje\_s1}} + {G_{air}})\text{。}$ (10)

 ${G_{eje\_2}} = {u_{eje\_2}} \cdot ({G_{eje\_s2}} + {G_{air}})\text{。}$ (11)

 ${G_{fw}} \cdot {c_{fw}} \cdot ({T_{fw}} - {T_{h\_i}}) = {G_h} \cdot ({h_{exh}} - {h_{hw}})\text{。}$ (12)

 ${G_h} = {G_{fw}} \cdot {c_{fw}} \cdot ({T_{fw}} - {T_{h\_i}})/({h_{exh}} - {h_{hw}})\text{。}$ (13)
2 基于多参数迭代法的二回路系统热平衡计算

 图 1 多参数迭代方法流程图 Fig. 1 Multi-parameter iterative method flow chart

 ${T_{fw}} = ({G_{fw\_1}} \cdot {T_{fw\_1}} + {G_{fw\_2}} \cdot {T_{fw\_2}})/({G_{fw\_1}} + {G_{fw\_2}})\text{。}$ (14)

 ${T_{ac\_o}} = {T_{ac\_i}} + {Q_{aeje}}/{c_{con}}/{G_{con}}\text{。}$ (15)

 ${T_{dea}} = {T_{con\_w}} + {G_{dea}} \cdot ({h_{exh}} - {h_{dea}})/{c_{con\_w}}/{G_{dea\_w}}\text{。}$ (16)

3 船用核动力装置二回路热平衡分析

3.1 核动力装置分系统热力参数计算

 图 2 主、辅凝水相对流量 Fig. 2 Relative flow rate of main and accessory condensate

 图 3 主、辅凝水相对温度 Fig. 3 Relative temperature of main and accessory condensate

3.2 船用核动力装置总体热力参数分析

 图 4 动力装置功率和耗汽量 Fig. 4 Power and steam consumption of power plant

 图 5 动力装置效率 Fig. 5 Efficiency of power plant
4 结　语

1）本文考虑船用核动力二回路系统结构和运行特点，建立的基于多参数迭代的热平衡方法，具有较高的精度和效率，能够方便快捷地计算出各耗汽设备的耗汽量，该方法也可用于核动力装置前期设计和热平衡校核。

2）本文计算了二回路系统在3种设计工况下主要设备的耗汽量和动力装置整体耗汽量，二回路系统中各主要设备耗汽量随着工况降低而下降，换热装置热负荷逐渐减小，与动力装置工作原理相吻合，能够体现二回路系统变工况下参数的变化规律。

3）展示了主轴功率、系统耗汽量和效率的变化趋势，揭示了变化趋势的成因：随着工况降低，各耗汽设备逐渐偏离效率最佳工况，导致动力装置整体效率显著下降。因此，在允许的情况下，应尽量使耗汽设备运行于最佳效率点附近，以提高系统效率。

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