Research on Transient Performance of Closed Feedwater Heater
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摘要: 加热器的运行特性决定回热系统的稳定性,进而影响着整个热力系统的性能。为了更好地了解加热器的运行,根据换热工质的不同,采用分段建模的方法,分别建立了加热器单相换热段和汽液两相换热段的数学模型,进而得到表面式给水加热器的通用瞬态数学模型。对两类换热面分别建模相对于以凝结段模型代替整个加热器分析,精度较好。通过对两类换热模型的组合,既可以得到高压加热器模型又能组合成低压加热器模型。以高压加热器为例,模拟了给水流量变化时,给水出口温度、蒸汽侧流量、温度、压力的变化,并对结果进行了分析,了解给水参数变化对加热器运行特性的影响。Abstract: Operating characteristics of the heater affect the stability of regenerative system and thereby the performance of the whole thermal system. To understand the operation of the heater better, according to the different working fluids in the heat exchanger, using the modular modeling method, the mathematical models for single phase heat transfer section and steam liquid two phase section of the heater were established, and then a common surface type transient mathematical model of the heater is obtained. Separate modeling for the two types of heating surface relative to that of the condensate section to replace the whole heater, the precision is improved. Through a combination of the two types of heat transfer model, the high pressure heater and the low pressure heater models were obtained. Taking a high pressure heater as an example, the simulation is applied to analyze changing progresses for working fluid flow, temperature and pressure under feedwater flow changes. This study shows how the change of feedwater parameter affects the heater's performance.
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Keywords:
- closed feedwater heater /
- transient /
- performance /
- model
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