An accurate critical heat flux（CHF） prediction method is the key factor for realizing the steady-state operation of a water-cooled divertor that works under one-sided high heating flux conditions.An improved CHF pre...An accurate critical heat flux（CHF） prediction method is the key factor for realizing the steady-state operation of a water-cooled divertor that works under one-sided high heating flux conditions.An improved CHF prediction method based on Euler＇s homogeneous model for flow boiling combined with realizable k-ε model for single-phase flow is adopted in this paper in which time relaxation coefficients are corrected by the Hertz-Knudsen formula in order to improve the calculation accuracy of vapor-liquid conversion efficiency under high heating flux conditions.Moreover,local large differences of liquid physical properties due to the extreme nonuniform heating flux on cooling wall along the circumference direction are revised by formula IAPWSIF97.Therefore,this method can improve the calculation accuracy of heat and mass transfer between liquid phase and vapor phase in a CHF prediction simulation of water-cooled divertors under the one-sided high heating condition.An experimental example is simulated based on the improved and the uncorrected methods.The simulation results,such as temperature,void fraction and heat transfer coefficient,are analyzed to achieve the CHF prediction.The results show that the maximum error of CHF based on the improved method is 23.7%,while that of CHF based on uncorrected method is up to 188%,as compared with the experiment results of Ref.[12].Finally,this method is verified by comparison with the experimental data obtained by International Thermonuclear Experimental Reactor（ITER）,with a maximum error of 6% only.This method provides an efficient tool for the CHF prediction of water-cooled divertors.展开更多
This paper presents a new scheme of flaw searching in surface modeling based on Euler Characteristic. This scheme can be applied to surface construction or reconstruction in computer. It is referred to as Euler Accomp...This paper presents a new scheme of flaw searching in surface modeling based on Euler Characteristic. This scheme can be applied to surface construction or reconstruction in computer. It is referred to as Euler Accompanying Test (EAT) algorithm in this paper. Two propositions in algebraic topology are presented, which are the foundation of the EAT algorithm. As the modeling is the first step for rendering in the animation and visualization, or computer-aided design (CAD) in related applications, the flaws can bring some serious problems in the final image or product, such as an artificial sense in animation rendering or a mistaken product in industry. To verify the EAT progressive procedure, a three-dimensional (3D) stamp model is constructed. The modeling process is accompanied by the EAT procedure. The EAT scheme is verified as the flaws in the stamp model are found and modified.展开更多
To decipher both shallow and deeper structural features that may control the emplacement of Kimberlite/Lamproite bodies in basement-exposed and covered areas, a detailed gravity survey was conducted on the northern ba...To decipher both shallow and deeper structural features that may control the emplacement of Kimberlite/Lamproite bodies in basement-exposed and covered areas, a detailed gravity survey was conducted on the northern bank of the Krishna River in the Kollarpur region of the Proterozoic Cuddapah Basin, within the Eastern Dharwar Craton. The study revealed an overall basement disposition dipping from south to north, controlled by a set of parallel E-W and NW-SE trending faults. In the northeastern part of the study area, the high-gravity zone corresponds to high-density source rocks at both shallow and deeper levels within the granite-gneissic basement. The residual gravity map highlights the disposition of high-density shallow source bodies as elliptical highs, located at Narlapur, Kalwakole, and Yelur in the eastern part. These residual gravity highs correspond to enclaves of amphibolite schist and BIF bands within granite-gneissic rocks. In the covered region of the southern part, the overall gravity low zone indicates the distribution of sediments with a thickness of about 1 km. Several NW-SE, N-S, NE-SW, and E-W structural features were delineated from the gravity survey. A major E-W gravity gradient along the northern margin of the Cuddapah and Kurnool groups of sediments is interpreted as a deep-rooted boundary fault. Parallel to this boundary fault, two NW-SE gravity gradients were identified in the northern and central parts within the Archean granite-gneissic basement rocks. Depth extensions of these major structures exceed 1 km. The N-S and NE-SW structures, although shorter in strike length, intersect with the major NW-SE and E-W structures. Some of these intersection zones correspond to known Kimberlite/Lamproite occurrences in both covered and basement-exposed areas. Based on these findings, potential loci for Kimberlite/Lamproite exploration have been delineated along the northern bank of the Krishna River in the Kollarpur region.展开更多
基金supported by the National Magnetic Confinement Fusion Science Program of China(No.2010GB104005)National Natural Science Foundation of China(No.51406085)
文摘An accurate critical heat flux（CHF） prediction method is the key factor for realizing the steady-state operation of a water-cooled divertor that works under one-sided high heating flux conditions.An improved CHF prediction method based on Euler＇s homogeneous model for flow boiling combined with realizable k-ε model for single-phase flow is adopted in this paper in which time relaxation coefficients are corrected by the Hertz-Knudsen formula in order to improve the calculation accuracy of vapor-liquid conversion efficiency under high heating flux conditions.Moreover,local large differences of liquid physical properties due to the extreme nonuniform heating flux on cooling wall along the circumference direction are revised by formula IAPWSIF97.Therefore,this method can improve the calculation accuracy of heat and mass transfer between liquid phase and vapor phase in a CHF prediction simulation of water-cooled divertors under the one-sided high heating condition.An experimental example is simulated based on the improved and the uncorrected methods.The simulation results,such as temperature,void fraction and heat transfer coefficient,are analyzed to achieve the CHF prediction.The results show that the maximum error of CHF based on the improved method is 23.7%,while that of CHF based on uncorrected method is up to 188%,as compared with the experiment results of Ref.[12].Finally,this method is verified by comparison with the experimental data obtained by International Thermonuclear Experimental Reactor（ITER）,with a maximum error of 6% only.This method provides an efficient tool for the CHF prediction of water-cooled divertors.
文摘This paper presents a new scheme of flaw searching in surface modeling based on Euler Characteristic. This scheme can be applied to surface construction or reconstruction in computer. It is referred to as Euler Accompanying Test (EAT) algorithm in this paper. Two propositions in algebraic topology are presented, which are the foundation of the EAT algorithm. As the modeling is the first step for rendering in the animation and visualization, or computer-aided design (CAD) in related applications, the flaws can bring some serious problems in the final image or product, such as an artificial sense in animation rendering or a mistaken product in industry. To verify the EAT progressive procedure, a three-dimensional (3D) stamp model is constructed. The modeling process is accompanied by the EAT procedure. The EAT scheme is verified as the flaws in the stamp model are found and modified.
文摘To decipher both shallow and deeper structural features that may control the emplacement of Kimberlite/Lamproite bodies in basement-exposed and covered areas, a detailed gravity survey was conducted on the northern bank of the Krishna River in the Kollarpur region of the Proterozoic Cuddapah Basin, within the Eastern Dharwar Craton. The study revealed an overall basement disposition dipping from south to north, controlled by a set of parallel E-W and NW-SE trending faults. In the northeastern part of the study area, the high-gravity zone corresponds to high-density source rocks at both shallow and deeper levels within the granite-gneissic basement. The residual gravity map highlights the disposition of high-density shallow source bodies as elliptical highs, located at Narlapur, Kalwakole, and Yelur in the eastern part. These residual gravity highs correspond to enclaves of amphibolite schist and BIF bands within granite-gneissic rocks. In the covered region of the southern part, the overall gravity low zone indicates the distribution of sediments with a thickness of about 1 km. Several NW-SE, N-S, NE-SW, and E-W structural features were delineated from the gravity survey. A major E-W gravity gradient along the northern margin of the Cuddapah and Kurnool groups of sediments is interpreted as a deep-rooted boundary fault. Parallel to this boundary fault, two NW-SE gravity gradients were identified in the northern and central parts within the Archean granite-gneissic basement rocks. Depth extensions of these major structures exceed 1 km. The N-S and NE-SW structures, although shorter in strike length, intersect with the major NW-SE and E-W structures. Some of these intersection zones correspond to known Kimberlite/Lamproite occurrences in both covered and basement-exposed areas. Based on these findings, potential loci for Kimberlite/Lamproite exploration have been delineated along the northern bank of the Krishna River in the Kollarpur region.
