In the precision cutting of difficult-to-process metals,surface thermal damage to a workpiece is a significant technical challenge.Although clean minimum quantity lubrication(MQL)technology,which replaces traditional ...In the precision cutting of difficult-to-process metals,surface thermal damage to a workpiece is a significant technical challenge.Although clean minimum quantity lubrication(MQL)technology,which replaces traditional pouring cooling,is used,inadequate heat dissipation remains an issue.Cryogenic air MQL(CAMQL),an eco-friendly technology,can enhance the heat transfer performance of the lubricating film in the cutting zone,offering excellent cooling and lubrication effects.However,the influence of jet and temperature parameters on the average particle size and distribution characteristics of atomized droplets is not well understood.This study first analyzes the evolution of lubricant physical properties and establishes a quantitative mapping relationship between cryogenic air temperature and physical parameters of lubricant.Next,the unstable fluctuation in the annular liquid film at the two-phase flow nozzle exit is observed and analyzed.A thickness model of annular liquid film is developed,revealing the effect of airflow field on the annular liquid film.Finally,a model for the average particle size of atomized droplets under CAMQL is established.Numerical analysis and validation experiments under different working conditions show that the measured values align with the theoretical values.Under an air pressure of 0.4 MPa and an air flow temperature of−50℃,the droplet particle size is 133.5μm,with an error of 8.2%.The effect of air pressure on particle size is greater than that of air flow temperature.Additionally,the distribution spans of droplet size under different conditions are analyzed,and the results demonstrated that low temperatures help shorten the interval between particle sizes and improve the relative uniformity of particle size distribution.This research provides a theoretical basis for the application of CAMQL technology in the cutting process.展开更多
Ion population fraction（IPF） calculations are very important to understand the radiative spectrum emitted from the hot dense matter. IPF calculations require detailed knowledge of all the ions and correlation intera...Ion population fraction（IPF） calculations are very important to understand the radiative spectrum emitted from the hot dense matter. IPF calculations require detailed knowledge of all the ions and correlation interactions between the electrons of an ion which are present in a plasma environment. The average atom models, e.g., screened hydrogenic model with l-splitting（SHML）, now have the capabilities for such calculations and are becoming more popular for in line plasma calculations. In our previous work [Ali A, Shabbir Naz G, Shahzad M S, Kouser R, Rehman A and Nasim M H 2018 High Energy Density Phys. 26 48], we have improved the continuum lowering model and included the exchange and correlation effects in SHML. This study presents the calculation of IPF using classical theory of fluctuation for our improved screened hydrogenic model with l-splitting（I-SHML） under local thermodynamic equilibrium conditions for iron and aluminum plasma over a wide range of densities and temperatures. We have compared our results with other models and have found a very good agreement among them.展开更多
High pressure investigations of matter involve the study of strong shock wave dynamics within the materials which gives rise to many thermal effects leading to dissociation of molecules,ionization of atoms,and radiati...High pressure investigations of matter involve the study of strong shock wave dynamics within the materials which gives rise to many thermal effects leading to dissociation of molecules,ionization of atoms,and radiation emission,etc.The response of materials experiencing a strong shock can be determined by its shock Hugoniot calculations which are frequently applied in numerical and experimental studies in inertial confinement fusion,laboratory astrophysical plasma,etc.These studies involve high energy density plasmas in which the radiation plays an important role in determining the energy deposition and maximum compressibility achieved by the shock within material.In this study,we present an investigation for the effect of radiation pressure on the maximum compressibility of the material using shock Hugoniot calculations.In shock Hugoniot calculations,an equation of state(EOS)is developed in which electronic contributions for EOS calculations are taken from an improved screened hydrogenic model with−l splitting(I-SHML)[High Energy Density Physics(2018)2648]under local thermodynamic equilibrium(LTE)conditions.The thermal ionic part calculations are adopted from the state of the art Cowan model while the cold ionic contributions are adopted from the scaled binding energy model.The Shock Hugoniot calculations are carried out for sodium and iron plasmas and our calculated results show excellent agreement with published results obtained by using either sophisticated self-consistent models or the first principle study.展开更多
Under local thermodynamic equilibriun conditions(LTE),the density and temperature of Na and Al plasmas are given,its absorption conefficient is calculated by More’s average atom model(AI),in which the photoabsorption...Under local thermodynamic equilibriun conditions(LTE),the density and temperature of Na and Al plasmas are given,its absorption conefficient is calculated by More’s average atom model(AI),in which the photoabsorption coefficients are calcalated in the hydrogenic approximation,and the results for aluminum have a good agreement compared with the experimental results.展开更多
We present the preliminary results of our code OPAQS（opacity calculation using quantum statistical model） that is based on the self consistent Hartree-Fock-Slater model for the average atom. The code is capable of p...We present the preliminary results of our code OPAQS（opacity calculation using quantum statistical model） that is based on the self consistent Hartree-Fock-Slater model for the average atom. The code is capable of performing robust calculations of average charge state, frequency-dependent and mean opacities. The accuracy of the atomic model is verified by comparing the calculations of average charge state with various published results. The monochromatic opacities for iron computed at different sets of temperatures and densities are compared with LEDCOP. The Rosseland and Planck opacities for iron and aluminum are validated with some state-of-the-art codes. The results are in good agreement with the published data.展开更多
基金supported by the following foundation items:the National Natural Science Foundation of China(Nos.52375447 and 52205481)the Shandong Provincial Natural Science Foundation of General Program(No.ZR2024ME205)+1 种基金the Special Fund of Taishan Scholars Project(No.tsqn202408220)the Shandong Provincial Natural Science Foundation of Youth Fund(No.ZR2021QE116).
文摘In the precision cutting of difficult-to-process metals,surface thermal damage to a workpiece is a significant technical challenge.Although clean minimum quantity lubrication(MQL)technology,which replaces traditional pouring cooling,is used,inadequate heat dissipation remains an issue.Cryogenic air MQL(CAMQL),an eco-friendly technology,can enhance the heat transfer performance of the lubricating film in the cutting zone,offering excellent cooling and lubrication effects.However,the influence of jet and temperature parameters on the average particle size and distribution characteristics of atomized droplets is not well understood.This study first analyzes the evolution of lubricant physical properties and establishes a quantitative mapping relationship between cryogenic air temperature and physical parameters of lubricant.Next,the unstable fluctuation in the annular liquid film at the two-phase flow nozzle exit is observed and analyzed.A thickness model of annular liquid film is developed,revealing the effect of airflow field on the annular liquid film.Finally,a model for the average particle size of atomized droplets under CAMQL is established.Numerical analysis and validation experiments under different working conditions show that the measured values align with the theoretical values.Under an air pressure of 0.4 MPa and an air flow temperature of−50℃,the droplet particle size is 133.5μm,with an error of 8.2%.The effect of air pressure on particle size is greater than that of air flow temperature.Additionally,the distribution spans of droplet size under different conditions are analyzed,and the results demonstrated that low temperatures help shorten the interval between particle sizes and improve the relative uniformity of particle size distribution.This research provides a theoretical basis for the application of CAMQL technology in the cutting process.
文摘Ion population fraction（IPF） calculations are very important to understand the radiative spectrum emitted from the hot dense matter. IPF calculations require detailed knowledge of all the ions and correlation interactions between the electrons of an ion which are present in a plasma environment. The average atom models, e.g., screened hydrogenic model with l-splitting（SHML）, now have the capabilities for such calculations and are becoming more popular for in line plasma calculations. In our previous work [Ali A, Shabbir Naz G, Shahzad M S, Kouser R, Rehman A and Nasim M H 2018 High Energy Density Phys. 26 48], we have improved the continuum lowering model and included the exchange and correlation effects in SHML. This study presents the calculation of IPF using classical theory of fluctuation for our improved screened hydrogenic model with l-splitting（I-SHML） under local thermodynamic equilibrium conditions for iron and aluminum plasma over a wide range of densities and temperatures. We have compared our results with other models and have found a very good agreement among them.
文摘High pressure investigations of matter involve the study of strong shock wave dynamics within the materials which gives rise to many thermal effects leading to dissociation of molecules,ionization of atoms,and radiation emission,etc.The response of materials experiencing a strong shock can be determined by its shock Hugoniot calculations which are frequently applied in numerical and experimental studies in inertial confinement fusion,laboratory astrophysical plasma,etc.These studies involve high energy density plasmas in which the radiation plays an important role in determining the energy deposition and maximum compressibility achieved by the shock within material.In this study,we present an investigation for the effect of radiation pressure on the maximum compressibility of the material using shock Hugoniot calculations.In shock Hugoniot calculations,an equation of state(EOS)is developed in which electronic contributions for EOS calculations are taken from an improved screened hydrogenic model with−l splitting(I-SHML)[High Energy Density Physics(2018)2648]under local thermodynamic equilibrium(LTE)conditions.The thermal ionic part calculations are adopted from the state of the art Cowan model while the cold ionic contributions are adopted from the scaled binding energy model.The Shock Hugoniot calculations are carried out for sodium and iron plasmas and our calculated results show excellent agreement with published results obtained by using either sophisticated self-consistent models or the first principle study.
文摘Under local thermodynamic equilibriun conditions(LTE),the density and temperature of Na and Al plasmas are given,its absorption conefficient is calculated by More’s average atom model(AI),in which the photoabsorption coefficients are calcalated in the hydrogenic approximation,and the results for aluminum have a good agreement compared with the experimental results.
文摘We present the preliminary results of our code OPAQS（opacity calculation using quantum statistical model） that is based on the self consistent Hartree-Fock-Slater model for the average atom. The code is capable of performing robust calculations of average charge state, frequency-dependent and mean opacities. The accuracy of the atomic model is verified by comparing the calculations of average charge state with various published results. The monochromatic opacities for iron computed at different sets of temperatures and densities are compared with LEDCOP. The Rosseland and Planck opacities for iron and aluminum are validated with some state-of-the-art codes. The results are in good agreement with the published data.
