Abstract With the development of both cryogenic and motor pump technologies, the cryogenic variable thrust liquid rocket engine that uses a motor pump is becoming an advanced power system for use in various aerospace missions. In the present study, this kind of engine system scheme is originally developed. The technical metrics of the engine system are primarily obtained based on the time history of the thrust for the descent engine in the lunar process as the mission profile. Subsequently, to satisfy the general mission requirements, the system schematic diagram is designed, followed by the design of the according subassemblies. The design highlights the pressure-drop models of the pipe and the cooling channels, and the mass model of the chamber. These models may improve computation precision. In this design scheme, based on the theoretical models and derivations, the state and structural parameter distributions for the system scheme are first proposed. Moreover, the influences of the tank material type, the battery type, and other parameters on the system scheme are analyzed. The results demonstrate that the pressurization system, due to its heavy battery and motors, constitutes the largest portion of the dry mass of the entire system, which may weaken the advantages compared with the conventional turbine pump system. The second-largest portion of the dry mass is composed of the propellant tanks, due to the restricted minimum wall thickness and the use of cryogenic materials. It is reported that, during the throttling process, there is a linear relationship between the route pressure losses of the cooling channels along with pipes and the 1.75 power of the chamber pressure. Based on this analysis, a better understanding of the proposed system scheme of the LOX/LCH4 variable thrust rocket engine that uses a motor pump can be obtained.

中文翻译：

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LOX/LCH4变推力液体火箭发动机电机泵系统方案设计

摘要 随着低温和马达泵技术的发展，采用马达泵的低温变推力液体火箭发动机正成为用于各种航天任务的先进动力系统。在目前的研究中，最初开发了这种发动机系统方案。发动机系统的技术指标主要是根据月球过程中下降发动机推力的时间历程作为任务剖面获得的。随后，为了满足总体任务要求，设计了系统原理图，然后设计了相应的子组件。该设计突出了管道和冷却通道的压降模型，以及腔室的质量模型。这些模型可以提高计算精度。在这个设计方案中，基于理论模型和推导，首先提出了系统方案的状态和结构参数分布。此外，还分析了罐体材料类型、电池类型等参数对系统方案的影响。结果表明，增压系统由于其电池和电机较重，构成了整个系统干质量的最大部分，这可能会削弱与传统涡轮泵系统相比的优势。由于最小壁厚的限制和低温材料的使用，干物质的第二大部分由推进剂罐组成。据悉，在节流过程中，冷却通道沿管道的路径压力损失与1。75 功率的腔室压力。基于此分析，可以更好地理解使用电动泵的 LOX/LCH4 可变推力火箭发动机的拟议系统方案。