火箭推进

基于再膨胀布雷顿回热循环,提出了一种新型空间双模式核热推进系统方案。针对使用氦作为工质的情况,对该推进系统发电模式下的性能进行了分析计算,获得了循环增温比和增压比以及再膨胀分配系数对发电模式循环性能的影响规律。结果表明:在同样设计参数下,此循环效率高于基本布雷顿回热循环,散热器面积小于基本布雷顿回热循环。循环增温比的增加会提高此循环效率,增压比的增加则会降低循环效率。对再膨胀分配系数的分析计算表明,在循环增压比分别为3和6的条件下,循环效率在膨胀分级比为0.83和1.05左右达到最大值。随着循环增压比的增大,循环输出功率最大值对应的分配系数也逐渐从左极值向右移动。此循环作为空间核热推进系统发电模式的循环方案,可以有效减小航天器的体积和重量。

In this paper, a new aerospace nuclear thermal propulsion system scheme is proposed on the basis of re-expand regenerative Brayton cycle. The system performance in power generation mode was simulated and analyzed while helium was used as the working medium. The influence of cycle temperature ratio, pressure ratio and reexpansion distribution coefficient of turbine on the power generation cycle performance were achieved. The results indicate that, with the same design parameters, the efficiency of this cycle is higher than that of regenerative cycle based on Brayton, but its radiator area is less than regenerative cycle based on Brayton. Cycle efficiency increases with the increase of cycle temperature ratio, but decreases with the increase of pressure ratio. The cycle efficiency reached the maximum value while pressure ratio distribution coefficient of turbine is at about 0.83 and 1.05 under the conditions of cycle pressure ratio at 3 and 6. With the increase of the cycle pressure ratio, the distribution coefficient corresponding to maximum value of the cycle output power moves to right from left extreme value. This cycle, when used as scheme for power generation mode of space nuclear thermal propulsion,can effectively reduce the size and weight of the spacecraft.

引言
1 双模式核热推进系统
2 循环及模型建立
3 循环计算及研究
4 结论

图1 双模式核热推进系统<br/>Fig.1 Bimodal nuclear thermal propulsion system

图1 双模式核热推进系统
Fig.1 Bimodal nuclear thermal propulsion system

图2 再膨胀空间布雷顿回热循环及其T-S图<br/>Fig.2 New re-expansion space Brayton regenerative cycle and its T-S scheme

图2 再膨胀空间布雷顿回热循环及其T-S图
Fig.2 New re-expansion space Brayton regenerative cycle and its T-S scheme

表1 初始设计参数<br/>Tab.1 Initial design parameters

表1 初始设计参数
Tab.1 Initial design parameters

表2 循环参数计算结果对比<br/>Tab.2 Parameter calculation results comparision

表2 循环参数计算结果对比
Tab.2 Parameter calculation results comparision

图3 循环效率
Fig.3 Cycle efficiency

图4 循环输出功率
Fig.4 Cycle output power

图5 循环吸热量<br/>Fig.5 Cycle heat absorption

图5 循环吸热量
Fig.5 Cycle heat absorption

图6 辐射散热器面积<br/>Fig.6 Area of heat radiator

图6 辐射散热器面积
Fig.6 Area of heat radiator

图7 效率和散热器面积随膨胀分级比变化趋势<br/>Fig.7 Variation of efficiency and radiator area with γp

图7 效率和散热器面积随膨胀分级比变化趋势
Fig.7 Variation of efficiency and radiator area with γp

图8 输出功率和吸热量随膨胀分级比变化趋势<br/>Fig.8 Output power and heat absorption variation with γp

图8 输出功率和吸热量随膨胀分级比变化趋势
Fig.8 Output power and heat absorption variation with γp

表3 给定工况下循环对比<br/>Tab.3 Cycle comparison at given working condition

表3 给定工况下循环对比
Tab.3 Cycle comparison at given working condition

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备注

引言

1 双模式核热推进系统

2 循环及模型建立

3 循环计算及研究

4 结论

期刊信息