Shock Waves最新文献

{"title":"Air-breathing rotating detonation engine supplied with liquid kerosene: propulsive performance and combustion stability","authors":"W. Perkowski, A. Bilar, M. Augustyn, M. Kawalec","doi":"10.1007/s00193-024-01185-2","DOIUrl":"https://doi.org/10.1007/s00193-024-01185-2","url":null,"abstract":"<p>Experimental results are presented for a rotating detonation engine supplied with liquid kerosene and preheated air without liquid or gaseous additions to the propellant mixture. Various combustion modes for the generic combustor geometry design were observed—from deflagration, through pulsed combustion and high-frequency instabilities, to stable detonation propagation. Attention was paid to detonation stability (if present), its characteristics, and the propulsive performance of the combustor with a focus on specific thrust and pressure gain through thrust and outlet total pressure measurement. These parameters measured for the observed modes were compared. The stability of the detonation combustion proved not to be critical to achieve high performance of the combustion chamber. For example, high performance was achieved for combustion modes with high-frequency instabilities.</p>","PeriodicalId":775,"journal":{"name":"Shock Waves","volume":"159 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Two-dimensional detailed numerical simulation of ammonia/hydrogen/air detonation: hydrogen concentration effects and transverse detonation wave structure","authors":"S. Kohama, T. Ito, N. Tsuboi, K. Ozawa, A. K. Hayashi","doi":"10.1007/s00193-024-01181-6","DOIUrl":"https://doi.org/10.1007/s00193-024-01181-6","url":null,"abstract":"<p>Numerical simulations on ammonia/hydrogen/air detonation are performed using a detailed reaction model to investigate the cellular instability and detonation dynamics as a function of hydrogen content. The UT-LCS model that includes 32 species and 213 elementary reactions is used in the present simulations. The fifth-order target compact nonlinear scheme captured the unstable detonation dynamics and the complicated flow structure including the propagation of a sub-transverse wave. The simulation performed with different hydrogen dilutions shows that the detonation propagates at the Chapman–Jouguet velocity for all cases, and the cell size for the ammonia/hydrogen mixing ratio <span>(alpha =0.3)</span> becomes approximately 10 times larger than that for <span>(alpha =1.0)</span> (hydrogen/air mixture). A transverse detonation produces a finescale cellular structure on the computed maximum pressure history. This complex shock formation is similar to those of a spinning detonation and two-dimensional propane/oxygen detonation. The cellular irregularity increases with decreasing hydrogen content because ammonia destabilizes the detonation cellular structure with a reduced activation energy of more than approximately 8.\u0000</p>","PeriodicalId":775,"journal":{"name":"Shock Waves","volume":"2016 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heat and momentum losses in ({text {H}}_{2})–({text {O}}_{2})–({text {N}}_{2}/{textrm{Ar}}) detonations: on the existence of set-valued solutions with detailed thermochemistry","authors":"F. Veiga-López,&nbsp;L. Faria,&nbsp;J. Melguizo-Gavilanes","doi":"10.1007/s00193-024-01182-5","DOIUrl":"10.1007/s00193-024-01182-5","url":null,"abstract":"<div><p>The effect of heat and momentum losses on the steady solutions admitted by the reactive Euler equations with sink/source terms is examined for stoichiometric hydrogen–oxygen mixtures. Varying degrees of nitrogen and argon dilution are considered in order to access a wide range of effective activation energies, <span>(E_{textrm{a,eff}}/R_{textrm{u}}T_{0})</span>, when using detailed thermochemistry. The main results of the study are discussed via detonation velocity-friction coefficient (<i>D</i>–<span>(c_{textrm{f}})</span>) curves. The influence of the mixture composition is assessed, and classical scaling for the prediction of the velocity deficits, <span>(D(c_{textrm{f,crit}})/D_{textrm{CJ}})</span>, as a function of the effective activation energy, <span>({E}_{textrm{a,eff}}/R_{textrm{u}} T_{0})</span>, is revisited. Notably, a map outlining the regions where <i>set-valued</i> solutions exist in the <span>(E_{textrm{a,eff}}/R_{textrm{u}}T_{0}text {--}{alpha })</span> space is provided, with <span>(alpha )</span> denoting the momentum–heat loss similarity factor, a free parameter in the current study.</p></div>","PeriodicalId":775,"journal":{"name":"Shock Waves","volume":"34 3","pages":"273 - 283"},"PeriodicalIF":1.7,"publicationDate":"2024-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00193-024-01182-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical investigation of the unsteady flow and wave dynamics in a wave rotor combustor","authors":"R. Zheng,&nbsp;J. Li,&nbsp;E. Gong,&nbsp;Q. Qin,&nbsp;Z. Feng","doi":"10.1007/s00193-024-01178-1","DOIUrl":"10.1007/s00193-024-01178-1","url":null,"abstract":"<div><p>The pressure gain combustion in wave rotors has the potential to significantly enhance the performance of gas turbine engines. Wave rotor design focuses on understanding the complex behavior of rotating channels, which is challenging due to high rotational speeds. To investigate the influence of different working conditions on the unsteady process within the wave rotor combustor, a simplified 24-channel model was established to study both the unsteady flow and the wave dynamics. The calculations indicate that, for the current port position adopted and a rotor speed of 4000 rpm, backflow occurs at the inlet port for various inlet pressures. By analyzing the working sequence of the wave rotor combustor, it is found that the inlet port does not close in time when the pre-compression wave returns. This delay results in reflected expansion waves or compression waves moving within the channel, which affect a portion of the pressure gain, leading to a damped sinusoidal trend in the pressure profiles within the channel. The optimal pre-pressurization effect can be achieved at a rotor speed of 2000 rpm for the test conditions considered, and the total pressure gain achieved was 6.3%. By adding hot-jet ignition, it is found that the shock wave and flame interact at least five times in the current simulation. The shock–flame interaction can greatly accelerate the process of chemical reactions. After the fourth interaction, the shock wave achieved local coupling with the flame, forming a local high-pressure area of 4 bar, verifying the effectiveness of the wave rotor as a constant-volume supercharging device.</p></div>","PeriodicalId":775,"journal":{"name":"Shock Waves","volume":"34 3","pages":"257 - 271"},"PeriodicalIF":1.7,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141256999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predicting detonation cell size of biogas–oxygen mixtures using machine learning models","authors":"S. Siatkowski, K. Wacko, J. Kindracki","doi":"10.1007/s00193-024-01164-7","DOIUrl":"https://doi.org/10.1007/s00193-024-01164-7","url":null,"abstract":"<p>Detonation cell size is a very important parameter describing the detonation process, used both for explosion safety analysis and for the design of detonation combustion chambers. Typically it has been studied either experimentally or by CFD simulations; both options are costly in terms of money and time. However, progress in the machine learning (ML) methods opened a third way of obtaining cell size. When trained properly, such models are capable of giving rapid, accurate predictions. Utilization of machine learning in the combustion field is gaining more attention from the research community. In this study, the process of training, testing, and evaluation of three different machine learning models for predicting biogas–oxygen mixture detonation cell size is presented. The models include: linear regression (LR), support vector regression (SVR), and neural network (NN). The dataset used for training and testing comes from the experimental studies conducted previously by the authors. It was shown that all the models give very good results with support vector regression proving to be the best.</p>","PeriodicalId":775,"journal":{"name":"Shock Waves","volume":"39 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141256932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prediction model for the risk of auditory and vestibular disfunction caused by a blast wave","authors":"J. Zhang,&nbsp;K. Chen,&nbsp;G. Li,&nbsp;W. Chen,&nbsp;Z. Duan,&nbsp;J. Kang,&nbsp;X. Liu,&nbsp;S. Zhang,&nbsp;H. Gan,&nbsp;S. Zhou,&nbsp;C. Weng,&nbsp;C. Ma,&nbsp;Y. Liu,&nbsp;T. Zhou,&nbsp;J. Wang","doi":"10.1007/s00193-024-01168-3","DOIUrl":"10.1007/s00193-024-01168-3","url":null,"abstract":"<div><p>Blast deafness and balance disorders are common consequences of modern warfare and terrorist actions. A predictive evaluation system can assist commanders in quickly gathering information on the incapacitation of combat personnel. However, a critical challenge to this goal was to clarify the dose–response relationship between the blast parameters and the severity of auditory and vestibular dysfunction. This paper describes the algorithms for a prediction model. We performed blast experiments to obtain data on animal auditory/vestibular dysfunction under different overpressures. Peak overpressure and positive phase duration of the blast wave were obtained by pressure measurements. The severity of auditory and vestibular dysfunction was established by the auditory brainstem response test, behavioral rating, and vestibular-evoked myogenic potentials tests. Test data were analyzed using receiver operating characteristic (ROC) curves and logistic regression analysis to obtain the overpressure limits for auditory/vestibular function and logistic regression curves for severity separately. The ROC curve analysis showed that the overpressure limit for the auditory function was 32.635 kPa and the vestibular function was 96.275 kPa. Logistic regression fitted curves illustrated the dose–response relationship between the coefficient <i>K</i>, normalized by peak overpressure and positive phase duration, and the risk probability of auditory and vestibular disfunction. The prediction model for the risk of auditory and vestibular disfunction severity (mild/moderate/severe) has been established based on the overpressure limit and dose–response relationship.</p></div>","PeriodicalId":775,"journal":{"name":"Shock Waves","volume":"34 4","pages":"327 - 338"},"PeriodicalIF":1.7,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141188927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Neuronal function spontaneously recovers in organotypic hippocampal slice cultures after repetitive exposure to occupational-level shock waves","authors":"C. Y. Kim,&nbsp;N. Varghese,&nbsp;M. Kleinberger,&nbsp;B. Morrison III","doi":"10.1007/s00193-024-01179-0","DOIUrl":"10.1007/s00193-024-01179-0","url":null,"abstract":"<div><p>Blast-induced traumatic brain injury has long been a prevalent health issue. There is growing concern for repeated exposures to low-level blasts with studies suggesting effects on neurological impairments and long-term health problems. The purpose of this study was to expand our understanding of the neurophysiological consequences of repetitive mild blast from a range of occupational exposure levels. We studied shock waves of peak overpressures ranging from 45 to 270 kPa and impulses of 54 to 295 kPa<span>(cdot )</span>ms. We observed the effects of these shock waves in organotypic hippocampal slice cultures generated from neonatal rat pups. This model allowed us to isolate the effects of blast on neuronal function without the confounding factors of scaling and peripheral systemic input. We found that blast severity and inter-blast interval were both integral in understanding non-injurious limits for blast exposure. With higher blast severity, the inter-blast interval needed to be extended to avoid deficits in long-term potentiation (LTP), a form of synaptic plasticity. Furthermore, blast exposures too close in time synergistically affected LTP negatively, producing a dose response with more exposures leading to greater deficits in LTP. Overall, even the lowest blast tested was capable of producing functional deficits under the appropriate conditions. These findings can aid in the improvement of safety and training protocols to set occupational exposure limits to avoid neurological impairments and negative long-term health effects.</p></div>","PeriodicalId":775,"journal":{"name":"Shock Waves","volume":"34 4","pages":"369 - 379"},"PeriodicalIF":1.7,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141188744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detonation wave reflection over a concave–convex cylindrical wedge","authors":"L. Q. Wang,&nbsp;H. H. Ma","doi":"10.1007/s00193-024-01176-3","DOIUrl":"10.1007/s00193-024-01176-3","url":null,"abstract":"<div><p>The transition between Mach reflection (MR) and regular reflection (RR) of gaseous detonations in argon-diluted stoichiometric hydrogen–oxygen was investigated experimentally using a wedge with a concave–convex surface. The continuous MR triple-point trajectory was recorded using the smoked foil technique, from which the transition angles for <span>({textrm{MR}}leftrightarrow {textrm{RR}})</span> transitions could be determined. Similar to the reflection of a non-reacting shock wave, the non-stationary hysteresis phenomenon was found for detonation reflection, i.e., the <span>({textrm{MR}}rightarrow {textrm{RR}})</span> transition angle was much larger than that for <span>({textrm{RR}} rightarrow {textrm{MR}})</span> transition. In addition, the <span>({textrm{RR}} rightarrow {textrm{MR}})</span> transition angle on the convex surface was smaller than that for detonation reflection over a single half-cylinder. This is opposite to what is found for non-reacting shock wave reflection.</p></div>","PeriodicalId":775,"journal":{"name":"Shock Waves","volume":"34 3","pages":"285 - 289"},"PeriodicalIF":1.7,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141188742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation into helmet–head shock wave interactions at low overpressures through free-field blasts and schlieren imagery","authors":"C. J. H. Thomas,&nbsp;C. E. Johnson","doi":"10.1007/s00193-024-01167-4","DOIUrl":"10.1007/s00193-024-01167-4","url":null,"abstract":"<div><p>Brain injuries in warfighters due to low-level blasts, even while wearing a helmet, are common. Understanding how the form of a shock wave changes when impacting a head donning a helmet may present solutions to reducing shock loading on the head, thereby reducing the prevalence of blast-induced traumatic brain injury. A manikin with PCB piezoelectric transducers throughout the head was exposed to low-pressure free-field blasts using an RDX-based explosive charge designed to output a side-on overpressure of 4 pounds per square inch (psi) [27.5 kilopascals (kPa)] with and without a helmet. Orientations of 0, 45, 90, 135, and 180 degrees were evaluated to observe changes in overpressure versus time (<i>p</i>(<i>t</i>)) waveforms. The waveforms were compared to schlieren imagery in which a shock wave impacted 3D-printed silhouettes of a warfighter donning a helmet, showing shock wave flow under the helmet at 0-, 90-, and 180-degree orientations. It was found that trapped shock waves under the helmet create regions of high overpressure and increase the duration of exposure, resulting in higher impulses imparted onto the head. While wearing a helmet, the 90-degree orientation resulted in the greatest reduction in overall peak overpressure, with an 8% decrease compared to the 0-degree orientation. In contrast, the 180-degree orientation led to an increase by 30%. For impulse, the 90-degree orientation showed the greatest reduction, with a decrease of 21%. The 0-degree orientation had the highest overall impulse among all orientations when wearing a helmet.</p></div>","PeriodicalId":775,"journal":{"name":"Shock Waves","volume":"34 4","pages":"399 - 412"},"PeriodicalIF":1.7,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141109025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detonation inhibition using retardant weight analysis for halogenated compounds","authors":"R. K. Singh, A. Dahake, A. V. Singh","doi":"10.1007/s00193-024-01175-4","DOIUrl":"https://doi.org/10.1007/s00193-024-01175-4","url":null,"abstract":"<p>The current study numerically evaluates the detonation inhibition effects of a range of halogenated compounds on hydrogen-air gaseous detonations. The halogenated compounds investigated in this research encompass halogen acids (HI, HBr, HCl, HF), halomethanes (<span>(hbox {CH}_{{3}}hbox {I})</span>, <span>(hbox {CH}_{{3}}hbox {Br})</span>, <span>(hbox {CH}_{{3}}hbox {Cl})</span>, <span>(hbox {CH}_{{3}}hbox {F})</span>), haloethenes (<span>(hbox {C}_{{2}}hbox {H}_{{3}}hbox {I})</span>, <span>(hbox {C}_{{2}}hbox {H}_{{3}}hbox {Br})</span>, <span>(hbox {C}_{{2}}hbox {H}_{{3}}hbox {Cl})</span>, <span>(hbox {C}_{{2}}hbox {H}_{{3}}hbox {F})</span>), haloethanes (<span>(hbox {C}_{{2}}hbox {H}_{{5}}hbox {I})</span>, <span>(hbox {C}_{{2}}hbox {H}_{{5}}hbox {Br})</span>, <span>(hbox {C}_{{2}}hbox {H}_{{5}}hbox {Cl})</span>, <span>(hbox {C}_{{2}}hbox {H}_{{5}}hbox {F})</span>), and complex halogenated compounds (<span>(hbox {CF}_{{3}}hbox {I})</span>, <span>(hbox {CF}_{{3}}hbox {Br})</span>, <span>(hbox {CF}_{{3}}hbox {Cl})</span>, <span>(hbox {CF}_{4})</span>). The study employs a one-dimensional ZND model with detailed chemical kinetics to examine the impact on detonation propagation by adding these halogenated compounds to hydrogen-air mixtures. The effectiveness of these inhibitors is evaluated based on their capacity to increase the induction length, the amount of inhibitor needed to attenuate a detonation wave, and their influence on the detonability of the gaseous mixture under both lean and rich conditions. The results indicate that several halogenated compounds exhibit superior inhibition properties compared to Halon 1301 (<span>(hbox {CF}_{{3}}hbox {Br})</span>). Specifically, <span>(hbox {C}_{{2}}hbox {H}_{{5}}hbox {Br})</span> leads to the most significant increase in the induction length, with HBr and <span>(hbox {C}_{{2}}hbox {H}_{{5}}hbox {I})</span> following closely, particularly at 20,000 ppmv concentration levels. However, it is worth noting that the inhibition efficiency also varies depending on the concentration of the inhibitor added to the gaseous <span>(hbox {H}_{{2}})</span>-air mixture. Moreover, based on retardant weight analysis, fluorinated compounds were found to be the most effective inhibitors, followed by chlorinated, brominated, and iodinated compounds across all categories of halogenated inhibitors.</p>","PeriodicalId":775,"journal":{"name":"Shock Waves","volume":"77 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140931960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}