The performance of a flotation circuit is largely the result of the operator's response to visual clues. This includes manipulation of the gas input and how it is distributed to cells in a bank. A new gas dispersi...The performance of a flotation circuit is largely the result of the operator's response to visual clues. This includes manipulation of the gas input and how it is distributed to cells in a bank. A new gas dispersion technology was presented which was conducted to perform characterization tests in Outokumpu 30 m3 and 50 m3 flotation cells installed at Thompson Vale's concentrator, and subsequent data analysis. The experimental program was designed to establish "as-found" baseline conditions for each cell of the two-parallel banks in the scavenger-cleaner and recleaner circuit, to select and characterize one typical cell in the two banks with either different frother concentrations or different air flow rates, and establish what variables can be manipulated in future characterization work. A three-parameter model was developed in order to link the bubble size and frother concentration. This relationship can be used to correlate gas dispersion change to improved metallurgical performance.展开更多
This study shows a novel three-dimensional （3D） parametric body model development using cross-section control and control algorithm retrieved from anthropometric survey. The 3D parametric body model was shaped into ...This study shows a novel three-dimensional （3D） parametric body model development using cross-section control and control algorithm retrieved from anthropometric survey. The 3D parametric body model was shaped into the most common body shape of the young Hong Kong female and be able to automatically change its critical body shape according to the user＇s critical body dimension inputs. The control algorithm controls the profile of the parametric model is retrieved from an anthropometric survey using 3D scanner to study the profile change of body and the relation between some critical body dimensions. Compared to the traditional anthropometric surveys, the 3D body scanner provides more accurate body dimension and information as well as new body shape measurements.展开更多
Based on statistical damage mechanics,the constitutive model of a rock underthree-dimensional stress was established by the law that the statistical strength of rockmicro-element obeys Weibull distribution.The acousti...Based on statistical damage mechanics,the constitutive model of a rock underthree-dimensional stress was established by the law that the statistical strength of rockmicro-element obeys Weibull distribution.The acoustic emission (AE) evolution model ofrock failure was put forward according to the view that rock damage and AE were consistent.Moreover,in the failure process of rock under three-dimensional stress,the change inrelationship between stress condition parameter and the characteristic parameters of AE,such as the event number and its change rate,were studied.Also,the rock AE characteristicunder uniaxial compression was analyzed in theory and verified with examples.Theresults indicate that the cumulative event number and change rate of AE in rock failure aredetermined by stress state parameter F.Along with the gradual increase of F,first the cumulativeevent number increases gradually,then rapidly,and then slowly after the stresspeak.The form of change rate of an event by increasing F is consistent with the distributionform of rock micro-element strength.The model explained the phenomenon that a relativelyquiet period of AE appears before rock rupture that is observed by many researchersin experiments.Verification examples indicate that the AE evolution model is consistentwith the test results,so the model is reasonable and correct.展开更多
The main technical problems that should be considered in the design of hydro-turbine generating units of Three Gorges Project (TGP) are analyzed;the key technical researches performed are summarized,and the parameters...The main technical problems that should be considered in the design of hydro-turbine generating units of Three Gorges Project (TGP) are analyzed;the key technical researches performed are summarized,and the parameters of hydro-turbine generating units are optimized through the study on key technical problems.The unit operation indicates that the performance of the hydro-turbine generating units is excellent,and the units can operate in a safe,stable and highly efficient mode for a long term.Therefore,it is verified effectively that the general technical design of units is scientific and rational.展开更多
In this paper, energy separation effect in a vortex tube has been investigated using a CFD model. Thenumerical simulation has been done due to the complex structure of flow. The governing equationshave been solved by ...In this paper, energy separation effect in a vortex tube has been investigated using a CFD model. Thenumerical simulation has been done due to the complex structure of flow. The governing equationshave been solved by FLUENT code in 2D and 3D compressible and turbulent model. The effects ofgeometrical and thermo-physical parameters have been investigated. The results have shown that theoptimum length to diameter ratio is from 25 to 35. Increasing the number of nozzles from 2 to 4 withconvergent shape is found to be an efficient configuration for the swirl generator. The optimum valueof orifice diameter to tube diameter ratio, for the maximum cold air temperature difference and efficiency,has been determined to be around 0.58. The results show that if the inlet pressure increases upto a critical value, the efficiency will increase. Nevertheless, if it increases to higher values, the efficiencywill decrease. Moreover, it is found out that increasing the cold fraction decreases the coldtemperature difference and efficiency.展开更多
基金Project(2012BAB14B05)supported by National Key Technology Research and Development Program of the Ministry of Science and Technology of China
文摘The performance of a flotation circuit is largely the result of the operator's response to visual clues. This includes manipulation of the gas input and how it is distributed to cells in a bank. A new gas dispersion technology was presented which was conducted to perform characterization tests in Outokumpu 30 m3 and 50 m3 flotation cells installed at Thompson Vale's concentrator, and subsequent data analysis. The experimental program was designed to establish "as-found" baseline conditions for each cell of the two-parallel banks in the scavenger-cleaner and recleaner circuit, to select and characterize one typical cell in the two banks with either different frother concentrations or different air flow rates, and establish what variables can be manipulated in future characterization work. A three-parameter model was developed in order to link the bubble size and frother concentration. This relationship can be used to correlate gas dispersion change to improved metallurgical performance.
文摘This study shows a novel three-dimensional （3D） parametric body model development using cross-section control and control algorithm retrieved from anthropometric survey. The 3D parametric body model was shaped into the most common body shape of the young Hong Kong female and be able to automatically change its critical body shape according to the user＇s critical body dimension inputs. The control algorithm controls the profile of the parametric model is retrieved from an anthropometric survey using 3D scanner to study the profile change of body and the relation between some critical body dimensions. Compared to the traditional anthropometric surveys, the 3D body scanner provides more accurate body dimension and information as well as new body shape measurements.
基金Supported by the Key Program of National Basic Research Program(973)of China(2005CB221505)the National Natural Science Foundation of China(2005E041503)
文摘Based on statistical damage mechanics,the constitutive model of a rock underthree-dimensional stress was established by the law that the statistical strength of rockmicro-element obeys Weibull distribution.The acoustic emission (AE) evolution model ofrock failure was put forward according to the view that rock damage and AE were consistent.Moreover,in the failure process of rock under three-dimensional stress,the change inrelationship between stress condition parameter and the characteristic parameters of AE,such as the event number and its change rate,were studied.Also,the rock AE characteristicunder uniaxial compression was analyzed in theory and verified with examples.Theresults indicate that the cumulative event number and change rate of AE in rock failure aredetermined by stress state parameter F.Along with the gradual increase of F,first the cumulativeevent number increases gradually,then rapidly,and then slowly after the stresspeak.The form of change rate of an event by increasing F is consistent with the distributionform of rock micro-element strength.The model explained the phenomenon that a relativelyquiet period of AE appears before rock rupture that is observed by many researchersin experiments.Verification examples indicate that the AE evolution model is consistentwith the test results,so the model is reasonable and correct.
文摘The main technical problems that should be considered in the design of hydro-turbine generating units of Three Gorges Project (TGP) are analyzed;the key technical researches performed are summarized,and the parameters of hydro-turbine generating units are optimized through the study on key technical problems.The unit operation indicates that the performance of the hydro-turbine generating units is excellent,and the units can operate in a safe,stable and highly efficient mode for a long term.Therefore,it is verified effectively that the general technical design of units is scientific and rational.
文摘In this paper, energy separation effect in a vortex tube has been investigated using a CFD model. Thenumerical simulation has been done due to the complex structure of flow. The governing equationshave been solved by FLUENT code in 2D and 3D compressible and turbulent model. The effects ofgeometrical and thermo-physical parameters have been investigated. The results have shown that theoptimum length to diameter ratio is from 25 to 35. Increasing the number of nozzles from 2 to 4 withconvergent shape is found to be an efficient configuration for the swirl generator. The optimum valueof orifice diameter to tube diameter ratio, for the maximum cold air temperature difference and efficiency,has been determined to be around 0.58. The results show that if the inlet pressure increases upto a critical value, the efficiency will increase. Nevertheless, if it increases to higher values, the efficiencywill decrease. Moreover, it is found out that increasing the cold fraction decreases the coldtemperature difference and efficiency.
