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Direct Comparison of Schlieren and Soot Foil Measurements of Detonation Cell Sizes 纹影和烟灰箔测量爆轰池尺寸的直接比较

Frontiers in Aerospace Engineering Pub Date : 2022-06-09 DOI: 10.3389/fpace.2022.892330

Mick Carter, D. Blunck

{"title":"Direct Comparison of Schlieren and Soot Foil Measurements of Detonation Cell Sizes","authors":"Mick Carter, D. Blunck","doi":"10.3389/fpace.2022.892330","DOIUrl":"https://doi.org/10.3389/fpace.2022.892330","url":null,"abstract":"Detonation-based combustion cycles have the potential to have higher thermodynamic efficiencies than the more common deflagration-based combustion cycles because the pressure of the products is higher than that of the reactants. The geometry to which a detonation is confined can have a strong influence on the detonation’s behavior, or even prevent a detonation from occurring. A key measurement that can be used to design detonation-based engines is the cell size of the mixture. The cell size is a characteristic length scale of a chemical mixture. For the first time, this study compares two methods of collecting cell size measurements within a single tube. This approach controls for the effects of tube geometry and surface roughness, which may confound studies whose schlieren and soot foil measurements have been collected from different tubes. This study indicates that measurements taken using the two measurement techniques agree to within experimental uncertainty (a difference of 1.3 mm, or 7%). Soot foil methods are generally preferable for detonation cell size measurements because soot foils provide larger triple point sample sizes per detonation and lower instrumentation costs relative to schlieren methods. Various sources of uncertainty are extensively analyzed and reported for the two techniques.","PeriodicalId":365813,"journal":{"name":"Frontiers in Aerospace Engineering","volume":"151 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114842704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Numerical Investigation on Spray Characteristics With Upstream Flow Pulsation of a Pintle Injector 尖形喷射器上游流动脉动时喷雾特性的数值研究

Frontiers in Aerospace Engineering Pub Date : 2022-05-26 DOI: 10.3389/fpace.2022.876191

Yuan Xie, W. Nie, Yuchao Gao, Yiheng Tong

{"title":"Numerical Investigation on Spray Characteristics With Upstream Flow Pulsation of a Pintle Injector","authors":"Yuan Xie, W. Nie, Yuchao Gao, Yiheng Tong","doi":"10.3389/fpace.2022.876191","DOIUrl":"https://doi.org/10.3389/fpace.2022.876191","url":null,"abstract":"The volume of fluid (VOF) model and the adaptive mesh refinement (AMR) method are used to study the spray characteristics of a gas–liquid pintle injector and the effects of mass flow pulsation of liquid on it. A pintle injector is a thrust adjusting device that changes the injection area using movable parts. Pressure pulsation in the supply pipeline is simulated by periodically changing the mass flow rate of the inlet. Spray characteristics with constant and pulsating upstream flows are compared with each other. The effect of frequency and amplitude of upstream liquid flow pulsation on the spray performance was studied. The results reveal that holding the mass flow rate of the upstream liquid flow constant, under the impact of gas flow, the liquid block, the liquid filament, and a large number of small droplets are peeled off from the liquid film. The film breakup position stays relatively fixed, and the spray has a conical shape. However, when the upstream liquid flow is pulsating, the film breakup position changes periodically, and the spray has a “Christmas tree”-shape. The pulsation frequency has little effect on the spray angle. But it strongly determines the droplet size and the spatial distribution of the spray. In addition, the pulsation amplitude can enhance the phenomenon of “Christmas tree.” With the increase in pulsation amplitude, the liquid film at the outlet of the pintle injector appears with a periodic phenomenon of “contraction–expansion.”","PeriodicalId":365813,"journal":{"name":"Frontiers in Aerospace Engineering","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114977902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

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