火箭推进

为研究喷注压降对空气加热器喷雾燃烧流场的影响规律,采用DPM离散相模型,结合考虑湍流燃烧效应的涡耗散模型对酒精/液氧/空气三组元加热器进行仿真计算,并与理论计算及试验结果进行对比,验证模型的准确性。仿真结果表明:在保持三组元流量恒定的条件下,提高空气喷注压降能够缩短酒精喷雾的雾化距离与火焰长度,当空气喷注压降提高后,能使喷雾距离缩短50%,火焰长度缩短40%,燃烧室内温度分布更加均匀,有利于提供满足试验需求的均匀热气流; 同时,降低酒精喷注压降能够减小酒精喷雾的穿透距离,使火焰更加集中于燃烧室轴线处; 当空气喷注压降超出工作范围时,火焰无法附着在喷嘴出口,容易造成加热器熄火; 过高的酒精喷注压降会使燃烧火焰周期性摆动,不利于燃烧室热防护。

In order to study the influence of injection pressure drop on the spray combustion flow field and combustion stability of the air heater. Discrete phase model(DPM)and eddy dissipation model considering the turbulent combustion effect were used to simulate the C2H5OH/LOx/Air tripropellant air heater, the simulation results were in good agreement with theoretical calculation and experiment, thereby the accuracy of the numerical models was verified. As the results shown, under the condition of maintaining a constant mass flow of the three-component propellant, increasing the air injection pressure drop could shorten the alcohol spray atomization distance and flame length, when the air injection pressure drop is increased to the critical pressure, the spray distance is shortened by 50% and the flame length is shortened by 40%. And the temperature distribution in the combustion chamber was more uniform, which could provide a uniform hot air flow to meet the test needs; reducing the alcohol injection pressure drop could reduce the alcohol spray penetration distance, and the flame was more concentrated on the axis of the combustion chamber. In addition, when the air injection pressure drop exceeded the working range, the flame would not be anchored to the injector outlet, which could cause the heater to shut down. Excessively high alcohol injection pressure drop would cause the combustion flame to oscillate periodically, which was not conducive to the thermal protection of the combustion chamber.

引言
1 计算模型
2 模型验证
3 喷注压降对喷雾燃烧流场影响
4 结论

图1 空气加热器计算域<br/>Fig.1 Computing domain of combustion heater

图1 空气加热器计算域
Fig.1 Computing domain of combustion heater

表1 仿真工况设置<br/>Tab.1 Simulation condition settings

表1 仿真工况设置
Tab.1 Simulation condition settings

图2 网格示意图<br/>Fig.2 Schematic diagram of grid

图2 网格示意图
Fig.2 Schematic diagram of grid

图3 温度沿燃烧室轴线的定量分布<br/>Fig.3 Quantitative distribution of temperature along the combustion chamber axis

图3 温度沿燃烧室轴线的定量分布
Fig.3 Quantitative distribution of temperature along the combustion chamber axis

表2 喷管出口燃气质量流量加权平均总温<br/>Tab.2 Weighted average total temperature of nozzle outlet gas mass flow

表2 喷管出口燃气质量流量加权平均总温
Tab.2 Weighted average total temperature of nozzle outlet gas mass flow

图4 冷试情况下液氧喷雾试验与仿真结果<br/>Fig.4 Liquid oxygen spray test and simulation results under cold test conditions

图4 冷试情况下液氧喷雾试验与仿真结果
Fig.4 Liquid oxygen spray test and simulation results under cold test conditions

图5 喷雾燃烧场计算与试验结果对比<br/>Fig.5 Spray combustion flow field calculation compared with experimental results

图5 喷雾燃烧场计算与试验结果对比
Fig.5 Spray combustion flow field calculation compared with experimental results

图6 喷雾流场分布<br/>Fig.6 Spray flow field distribution

图6 喷雾流场分布
Fig.6 Spray flow field distribution

图7 酒精液滴粒径分布<br/>Fig.7 Alcohol droplet size distribution

图7 酒精液滴粒径分布
Fig.7 Alcohol droplet size distribution

$图8 对称面射流穿透深度与酒精质量分数分布<br/>Fig.8 Symmetrical surface jet penetration depth and alcohol mass fraction distribution$

图8 对称面射流穿透深度与酒精质量分数分布
Fig.8 Symmetrical surface jet penetration depth and alcohol mass fraction distribution

图9 燃烧室温度分布云图(工况1、工况2、工况3)<br/>Fig.9 Combustion chamber temperature distribution(case 1,case 2,case 3)

图9 燃烧室温度分布云图(工况1、工况2、工况3)
Fig.9 Combustion chamber temperature distribution(case 1,case 2,case 3)

图10 流向截面温度定量分布图<br/>Fig.10 Quantitative distribution of flow direction cross-section temperature

图10 流向截面温度定量分布图
Fig.10 Quantitative distribution of flow direction cross-section temperature

图11 酒精喷雾沿流向方向(y=0 mm)分布<br/>Fig.11 Alcohol spray distribution along the direction of flow(y=0 mm)

图11 酒精喷雾沿流向方向(y=0 mm)分布
Fig.11 Alcohol spray distribution along the direction of flow(y=0 mm)

图12 燃烧室温度分布云图(工况4、工况5)<br/>Fig.12 Combustion chamber temperature distribution(case 4,case 5)

图12 燃烧室温度分布云图(工况4、工况5)
Fig.12 Combustion chamber temperature distribution(case 4,case 5)

表3 燃烧不稳定仿真工况设置<br/>Tab.3 Combustion instability simulation condition settings

表3 燃烧不稳定仿真工况设置
Tab.3 Combustion instability simulation condition settings

图13 燃烧室温度与酒精分布云图<br/>Fig.13 Combustion chamber temperature and alcohol distribution

图13 燃烧室温度与酒精分布云图
Fig.13 Combustion chamber temperature and alcohol distribution

图14 燃烧室压力振荡<br/>Fig.14 Combustion chamber pressure oscillation

图14 燃烧室压力振荡
Fig.14 Combustion chamber pressure oscillation

图15 半个振荡周期内的喷雾燃烧流场<br/>Fig.15 Spray combustion flow field for half an oscillation cycle

图15 半个振荡周期内的喷雾燃烧流场
Fig.15 Spray combustion flow field for half an oscillation cycle

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备注

引言

1 计算模型

2 模型验证

3 喷注压降对喷雾燃烧流场影响

4 结论

期刊信息