﻿ 无焰燃烧斯特林发动机加热器仿真与优化
 舰船科学技术  2020, Vol. 42 Issue (6): 121-125    DOI: 10.3404/j.issn.1672-7649.2020.06.024 PDF

Simulation and optimization of flameless combustion Stirling engine heater
JIN Xu-dong, LV Tian, HUANG Xiao-yu, HUANG You-ming
Shanghai Marine Diesel Engine Research Institute, Shanghai 201203, China
Abstract: The effect of the improved type B Stirling engine heater is unsatisfactory compared with type A Stirling engine heater. Therefore, the structure and other characteristics of the two heaters are analyzed and the optimization is also carried out by numerical simulation. The numerical results show that the total heat exchange remains the same although the lengths of heater tube and fin area of type B heater increase. In addition, the increase of heater tube length leads to the increase of dead volume, which is unfavorable to the performance of the engine. Improving the arrangement of type B heater tube and increasing the size of tube diameter can promote the match of flue gas flow field and increase the heat transfer capacity of the front row. Increasing the distance between the top of heater tube and the outlet of cyclone is helpful to improve heat transfer capacity.
Key words: stirling engine     diesel combustion     the heater     numerical simulation
0 引　言

1 模型介绍

 图 1 外燃系统计算模型 Fig. 1 Simulated external combustion system model

 图 2 外燃系统计算模型网格 Fig. 2 Simulated external combustion system model grid

2 外燃系统模拟分析 2.1 流场

 图 3 定壁温条件下A，B型加热器外燃系统流场 Fig. 3 Flow field of external combustion system of type A and B heaters at constant wall temperature
2.2 温度场

 图 4 定壁温条件下A，B型加热器外燃系统温度云图 Fig. 4 Temperature flied of external combustion system of type A and B heaters at constant wall temperature
2.3 管壁换热能力（换热器系数）

 图 5 定壁温条件下A、B型加热器管排换热能力 Fig. 5 Heat transfer capacity of type A and B heater tubes at constant wall temperature

3 优化设计分析 3.1 模型改进

1）改进B型加热器管排布置方式，采用前排斜布置减短管高，增加管顶部与旋流器出口距离，希望使得流场与烟气相匹配，同时减小无益容积提升整机效率；

2）变化管径大小，改变前排换热面积。

 图 6 改进的B型加热器外燃系统模型 Fig. 6 Improved heater external combustion system model of type B heater
3.2 数值分析

 图 7 改进的B型加热器外燃系统流场 Fig. 7 Flow flied of improved heater external combustion system model of type B heater

 图 8 改进的B型加热器外燃系统温度云图 Fig. 8 Temperature flied of improved heater external combustion system model of type B heater

 图 9 改进的B型加热器管排换热能力 Fig. 9 Heat transfer capacity of improved type B heater tubes

4 结　语

1）仅管B型加热器增加了加热管长度和翅片面积，但A，B两种加热器换热能力相当，前后排管换热比例相差不大，此外加热管长度增加反而导致整机死容积增加，对整机性能不利。

2）A、B两种加热器的外燃系统中二者流场与烟气匹配度均较低，导致加热器前排以及顶部和后排上部的利用率较低。

3）改进加热器管排布置方式，采用前排斜布置，并增大管径大小，能够促进其流场与烟气相匹配，其换热总量相当，但前排换热占比增加，可降低后排翅片钎焊质量的负面影响。

4）增加加热器管顶部与旋流器出口距离，使烟气冲刷前排管子中间，更有助于提高换热能力，但实际布置时要综合考虑整机外形尺寸和维修性等因素。

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