{"title":"裂隙和方形活塞快速压缩机的热学和空气动力学特征:扩展绝热核心假说的有效性,产生受控温度梯度","authors":"H. Ossman, C. Strozzi, J. Sotton, M. Bellenoue","doi":"10.1007/s10494-023-00465-8","DOIUrl":null,"url":null,"abstract":"<div><p>Rapid compression machines (RCM) are well-known tools to study the autoignition phenomenon under engine-relevant conditions. Covering a wide range of pressure and temperature at the top dead center (TDC), it can be employed with different types of mixtures and thermal stratification. Creating a homogeneous hot core region after compression in the combustion chamber is one of the challenges to overcome for RCM studies. The objective of the present work is to characterize from aerodynamic and thermal points of view a new configuration in the optical RCM of Pprime Institute. The latter aims at ensuring a wider adiabatic core region in terms of time and space through the installation of a creviced piston, specifically adapted to the square cross-section cylinder of this particular RCM. For this purpose, the internal flow has been qualified using high-frequency Particle Image Velocimetry with different laser sheet locations. Temperature variation during and after compression is measured at several positions with respect to the cylinder head, using thermocouples with wire diameter of 7.6 µm. It is observed that the piston cavity is able to collect the boundary layer created during compression and maintain a wide region at low velocity after the top dead center. Furthermore, it is demonstrated that different temperature gradient values can be generated and quantified within the adiabatic core region through differential heating of the chamber. This feature is promising for future works devoted to the analysis of combustion regimes. More generally, the thin wire thermocouples are shown to be accurate and reliable sensors to measure temperature in severe and transient pressure and temperature conditions specific to RCM internal flows.</p></div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":null,"pages":null},"PeriodicalIF":2.0000,"publicationDate":"2023-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Thermal and Aerodynamic Characterization of a Creviced and Squared Piston Rapid Compression Machine: Extending the Validity of the Adiabatic Core Hypothesis, Generating Controlled Temperature Gradients\",\"authors\":\"H. Ossman, C. Strozzi, J. Sotton, M. Bellenoue\",\"doi\":\"10.1007/s10494-023-00465-8\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Rapid compression machines (RCM) are well-known tools to study the autoignition phenomenon under engine-relevant conditions. Covering a wide range of pressure and temperature at the top dead center (TDC), it can be employed with different types of mixtures and thermal stratification. Creating a homogeneous hot core region after compression in the combustion chamber is one of the challenges to overcome for RCM studies. The objective of the present work is to characterize from aerodynamic and thermal points of view a new configuration in the optical RCM of Pprime Institute. The latter aims at ensuring a wider adiabatic core region in terms of time and space through the installation of a creviced piston, specifically adapted to the square cross-section cylinder of this particular RCM. For this purpose, the internal flow has been qualified using high-frequency Particle Image Velocimetry with different laser sheet locations. Temperature variation during and after compression is measured at several positions with respect to the cylinder head, using thermocouples with wire diameter of 7.6 µm. It is observed that the piston cavity is able to collect the boundary layer created during compression and maintain a wide region at low velocity after the top dead center. Furthermore, it is demonstrated that different temperature gradient values can be generated and quantified within the adiabatic core region through differential heating of the chamber. This feature is promising for future works devoted to the analysis of combustion regimes. More generally, the thin wire thermocouples are shown to be accurate and reliable sensors to measure temperature in severe and transient pressure and temperature conditions specific to RCM internal flows.</p></div>\",\"PeriodicalId\":559,\"journal\":{\"name\":\"Flow, Turbulence and Combustion\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.0000,\"publicationDate\":\"2023-08-19\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Flow, Turbulence and Combustion\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://link.springer.com/article/10.1007/s10494-023-00465-8\",\"RegionNum\":3,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"MECHANICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Flow, Turbulence and Combustion","FirstCategoryId":"5","ListUrlMain":"https://link.springer.com/article/10.1007/s10494-023-00465-8","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MECHANICS","Score":null,"Total":0}
Thermal and Aerodynamic Characterization of a Creviced and Squared Piston Rapid Compression Machine: Extending the Validity of the Adiabatic Core Hypothesis, Generating Controlled Temperature Gradients
Rapid compression machines (RCM) are well-known tools to study the autoignition phenomenon under engine-relevant conditions. Covering a wide range of pressure and temperature at the top dead center (TDC), it can be employed with different types of mixtures and thermal stratification. Creating a homogeneous hot core region after compression in the combustion chamber is one of the challenges to overcome for RCM studies. The objective of the present work is to characterize from aerodynamic and thermal points of view a new configuration in the optical RCM of Pprime Institute. The latter aims at ensuring a wider adiabatic core region in terms of time and space through the installation of a creviced piston, specifically adapted to the square cross-section cylinder of this particular RCM. For this purpose, the internal flow has been qualified using high-frequency Particle Image Velocimetry with different laser sheet locations. Temperature variation during and after compression is measured at several positions with respect to the cylinder head, using thermocouples with wire diameter of 7.6 µm. It is observed that the piston cavity is able to collect the boundary layer created during compression and maintain a wide region at low velocity after the top dead center. Furthermore, it is demonstrated that different temperature gradient values can be generated and quantified within the adiabatic core region through differential heating of the chamber. This feature is promising for future works devoted to the analysis of combustion regimes. More generally, the thin wire thermocouples are shown to be accurate and reliable sensors to measure temperature in severe and transient pressure and temperature conditions specific to RCM internal flows.
期刊介绍:
Flow, Turbulence and Combustion provides a global forum for the publication of original and innovative research results that contribute to the solution of fundamental and applied problems encountered in single-phase, multi-phase and reacting flows, in both idealized and real systems. The scope of coverage encompasses topics in fluid dynamics, scalar transport, multi-physics interactions and flow control. From time to time the journal publishes Special or Theme Issues featuring invited articles.
Contributions may report research that falls within the broad spectrum of analytical, computational and experimental methods. This includes research conducted in academia, industry and a variety of environmental and geophysical sectors. Turbulence, transition and associated phenomena are expected to play a significant role in the majority of studies reported, although non-turbulent flows, typical of those in micro-devices, would be regarded as falling within the scope covered. The emphasis is on originality, timeliness, quality and thematic fit, as exemplified by the title of the journal and the qualifications described above. Relevance to real-world problems and industrial applications are regarded as strengths.