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Study Of The Space Performance Of Water-Based Rocket Propulsion System

Posted on:2012-01-21Degree:DoctorType:Dissertation
Country:ChinaCandidate:Z LinFull Text:PDF
GTID:1112330362461961Subject:Aerospace Propulsion Theory and Engineering
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Water based rocket propulsion system is a space propulsion system, which contains a proton exchange membrane fuel cell (PEMFC) subsystem, a solid polymer electrolyzer (SPE) subsystem and a space GH2/GO2 thruster subsystem. Comparing to custom propulsion system, water based propulsion system has the advantages of high specific impulse, high power ratio, no pollution and good compatibility with space life sustain system. So, water based propulsion system is promising in the future space applications. In this paper, theoretic analysis, numerical simulation and experimental studies are introduced, and the space performance of water based propulsion, from its subsystems to the whole system, are gradually studied.In order to study the space performance of PEMFC, firstly, the conventional performance of PEMFC on the earth is studied. Then, the effect of different gravity situation on the physical and chemistry process of PEMFC is studied. Furtherly, the effect of the micro gravity environment on the PEMFC performance is studied. It is indicated that, on the earth, the gravity can be suitably utilized to improve the PEMFC performance. In space, as no gravity can be utilized, the PEMFC performance will slightly decline. But, the slight decline of the PEMFC performance can be greatly eliminated through controlling the liquid water generation rate inside the PEMFC or providing enough inlet flow velocity for the PEMFC flow channels.In order to study the space performance of SPE, the configuration and characteristic of three typical SPE are compared with each other. Static water feed SPE (SWF-SPE) is considered the most suitable SPE to space application. According to the operating characteristics of SWF-SPE, a simulation model is constructed. Based on this model, several results are concluded: the membrane of SWF-SPE is more possibly to dehydrate, which will lead to smaller current density limitation and lower gas producing rate. Thicker proton exchange membrane is in favor of improving the utmost gas producing rate and the electrolyte efficiency of SWF-SPE. In order to evaluate the space performance of the GH2/GO2 thruster adapting to water based propulsion system. The aspects of ignition method, fuel spray method, heat resistant method, designed combustion pressure and designed mixture ratio are discussed. It is indicated that well designed thruster can make the real specific impulse of water based propulsion beyond 400 s.According to the conclusion mentioned above, the performance of conventional PEMFC and the reported SWF-SPE are used to evaluate the space performance of the whole water based propulsion system. The specific impulse of the whole system is considered as 400 s. In this case, comprehensive analysis of the whole water based propulsion is introduced. It is indicated water based propulsion system can obtain great mass advantages because of its high specific impulse and high power ratio. But, the limitation of its tank mass, SWF-SPE mass and electrolyte power will lead to some limitation of its space application.In order to quantitatively analyze the performance of water based propulsion system, the custom propulsion system of DFH-4 is replaced by water based propulsion system. Based on the actual process of DFH-4, a specific space mission is constructed and analyzed. It is indicated that, during the orbit transfer mission, water based propulsion system prefer to the strategy of higher thruster, shorter single step fire and more transfer steps; During the whole space mission, water based propulsion system can save 706 kg mass for the DFH-4 satellite, which is 1.72 times the payload of DFH-4. But the system will increase the orbit change time to more than 56 days.On the addition, a separated water based propulsion experimental system is constructed in this paper. Some important subsystem experiments and whole system analysis are introduced. According to The catalytic ignition of the GH2/GO2 thruster based on the thruster subsystem, the feasibility of the GH2/GO2 thruster catalytic ignition is validated. And the law of GH2/GO2 catalytic ignition is obtained. According to the primary power generation experiment of PEMFC subsystem and the primary electrolytic experiment of SPE subsystem, the power generation and electrolytic performance of these two subsystems are obtained. Based on the experiment results, the whole system analysis is conducted. It is indicated the subsystems of the water based rocket propulsion system and the space missions are restraint with each other and need to be adapt to each other. For different space missions, the configuration of the three subsystems needs to be carefully optimized. The experimental system primarily realized the conception of water based rocket propulsion system. It is the accordance and foundation of further studies.
Keywords/Search Tags:water based rocket propulsion system, PEMFC, SWF-SPE, space performance, space mission, mass advantage
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