摘要 :
In this paper, the optimization scheme of a centrifugal fan under the constraints of the total pressure difference, efficiency and shaft power was carried out. The blade inlet angle ?1A and the blade outlet angle ?2A of the centri...
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In this paper, the optimization scheme of a centrifugal fan under the constraints of the total pressure difference, efficiency and shaft power was carried out. The blade inlet angle ?1A and the blade outlet angle ?2A of the centrifugal impeller were optimized using the Response Surface Methodology (RSM). Nine optimization cases were presented. The aerodynamic performance and the flow field of the optimized model were carefully compared with the original model. The results show that the total pressure difference and the total-pressure efficiency increase by 5.7% and 4.2% respectively after the optimization. Compared with the original fan, the flow field inside the impeller of the optimized fan has been improved. The flow separation existing around the blade suction surface outlet is suppressed significantly. For fields in the volute, the optimization scheme has reduced the local vortex intensity and weakened the vortex scale. The flow field stability around the volute tongue is also correspondingly improved.
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Response surface methodology was used to optimize a medium for a red-pigmented marine bacterium S-9801 strain (Flavobacterium sp.). In the first optimization step the influence of yeast extract, peptone, glucose and sodium chlorid...
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Response surface methodology was used to optimize a medium for a red-pigmented marine bacterium S-9801 strain (Flavobacterium sp.). In the first optimization step the influence of yeast extract, peptone, glucose and sodium chloride on pigment production was evaluated using a fractional factorial design. Pigment production was positively influenced by glucose and sodium chloride while other components had no significant effect. In the second step the path of steepest ascent was used to approach the optimal region of the medium composition. In the third step the optimal concentration of glucose and sodium chloride was determined by a central composite design and response analysis. The optimized medium allowed pigment production (A 535～650) to be increased from 0.137 to0.559, being 320% higher than the original medium.
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Concepts and techniques of response surface methodology have been widely applied in many branches of engineering, especially in the chemical and manufacturing areas. This paper presents an application of the methodology in a magne...
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Concepts and techniques of response surface methodology have been widely applied in many branches of engineering, especially in the chemical and manufacturing areas. This paper presents an application of the methodology in a magnetic crystal Czochralski growth system for single crystal silicon to optimize the oxygen concentration at the crystal growth interface in a cusp magnetic field. The simulation demonstrates that the response surface methodology is a feasible algorithm for the optimization of the Czochralski crystal growth process.
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[Objectives]This study was conducted to investigate the extraction process of quiona(Cheuopodium quinoa)leaves.[Methods]Firstly,single factor experiments were carried out with the volume fraction of ethanol,extraction time,extract...
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[Objectives]This study was conducted to investigate the extraction process of quiona(Cheuopodium quinoa)leaves.[Methods]Firstly,single factor experiments were carried out with the volume fraction of ethanol,extraction time,extraction temperature and liquid-to-material ratio as factors.Based on the single factor experiments,a response surface test was designed by the central composite design method of Design-Expert software to establish a mathematical model.[Results]The optimal extraction conditions of quinoa flavonoids were obtained as follows:the ethanol volume fraction of 70%,the liquid-to-material ratio at 30∶1,the extraction time of 100 min and the extraction temperature at 60℃.[Conclusions]The results of the study are stable with small deviation,and can provide reference for related processes.
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Ultrasonic extraction conditions of polyphenols from the needles of black pine ( Pinus thunbergii ) were optimized by single factors analysis and Box-Behnken experiment design. The results showed that both of ethanol concentration...
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Ultrasonic extraction conditions of polyphenols from the needles of black pine ( Pinus thunbergii ) were optimized by single factors analysis and Box-Behnken experiment design. The results showed that both of ethanol concentration and ultrasonic time had a significant effect on polyphenol extraction, and there was significant interaction between any two variables in the three parameters of ethanol concentration, ultrasonic temperature and ultrasonic time. The optimal parameters for polyphenol extraction were the ethanol concentration of 52.67%, ultrasonic temperature at 49.21 ℃and ultrasonic time of 30.76 min. Under these conditions, the actual content of polyphenols was close to the predicted value. Therefore, the process can be used to extract polyphenols from black pine needles.
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In this study, coconut husk cellulose was employed as a cost-effective and environmentally friendly adsorbent to eliminate methylene blue (MB) dye from aqueous solutions. The successful development of response surface methodology ...
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In this study, coconut husk cellulose was employed as a cost-effective and environmentally friendly adsorbent to eliminate methylene blue (MB) dye from aqueous solutions. The successful development of response surface methodology paired with a central composite design (RSM-CCD) enabled the optimization and modelling of the adsorption process. The study investigated the individual and combined effects of three variables (pH, contact time, and initial MB dye concentration) on the adsorption of MB dye onto coconut husk cellulose. The developed RSM-CCD model exhibited a remarkable degree of precision in predicting the removal efficiency of MB dye within the specified experimental parameters. This was demonstrated by the strong regression parameters, with an R2 value of 99.79% and an adjusted R2 value of 99.6%. The study depicted that the optimal parameters for attaining a 98.8827% removal of MB dye using coconut husk cellulose were as follows: an initial MB dye concentration of 30 mg∙L−1, contact time of 120 minutes, and pH 7 at a fixed adsorbent dose of 0.5 g. The Freundlich isotherm model provided the most satisfactory description of the equilibrium adsorption isotherms, suggesting that MB dye adsorption onto coconut husk cellulose occurs on a heterogeneous surface. The experimental results demonstrated a strong agreement with the pseudo-second-order kinetics model, indicating that the number of active sites present on the cellulose adsorbent predominantly influences the adsorption process of MB dye. Additionally, the adsorbent made from coconut husk cellulose exhibited the potential to be reused, as it retained its efficiency for a maximum of three cycles of adsorption of MB dye. The results of this study show that coconut husk cellulose has the potential to be an effective and sustainable adsorbent for removing MB dye from aqueous solutions.
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Eucalyptus sawdust is a residue from fast-growing forest processing.Utilization of Eucalyptus sawdust as fuel by co-pelletization with natural forest sawdust could solve problems of waste disposal and material supply limitation of...
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Eucalyptus sawdust is a residue from fast-growing forest processing.Utilization of Eucalyptus sawdust as fuel by co-pelletization with natural forest sawdust could solve problems of waste disposal and material supply limitation of pellet production.This work targeted at providing a useful reference for improving pellet properties and optimizing variable combinations.Experiments were arranged using response surface methodology with a central composite design and carried out using a uniaxial piston-cylinder densification apparatus.Based on the analysis of variance of effects of variables on responses,the optimal models were all selected as quadratic and expressed in the form of regression equations.The differences between adjusted R2 and predicted R2 are all within 0.2 and the adequate precision is all greater than four illustrating the reliability of the established models.The optimal variable combinations were obtained according to the desired response goals and validation experiments were conducted.Errors between response predicted and actual values were calculated and applied to improve the model accuracy.After modification,final errors were reduced to less than 9%and could be accepted by pellet production.Experimental results also demonstrated that pellet properties and higher heating value were all increased by co-pelletization and optimization.This will be very beneficial for pellet application.Furthermore,these results could provide the required data for designing a suitable machine of pellet production.
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