Investigation on the Effect of Impeller Design Parameters on Performance of a Low Specific Speed Centrifugal Pump Using Taguchi Optimization Method

In order to investigate the effect of blade design on pump performance, a CFD analysis was carried out, and the results were compared with experimental performance data of a low specific speed radial pump, which presents a good agreement. After model verification, the effect of impeller geometrical parameters includes blade outlet angle, wrap angle, and width at the exit, was investigated on the pump’s performance. Moreover, these parameters were chosen on three levels using an L9 orthogonal standard array of the Taguchi optimization method. The efficient levels of variables were calculated using the analysis of variance (ANOVA) method. The results revealed that impeller width at exit and blade outlet angle is the most effective pump shaft power and efficiency parameters. To minimize power, the optimal levels are the outlet angle of 27∘∘, wrap angle of 150∘∘, and width at the exit of 9 mm. Further, an outlet angle of 23∘∘, a wrap angle of 155∘∘, and a width at the exit of 9 mm lead to maximum pump efficiency. According to the validation simulations, an increase of 2.4% inefficiency and a minimum power of 3.9KW were achieved. The Overall Evaluation Criteria (OEC) technique revealed that considering 23∘∘, 160∘∘, and 9 mm for outlet angle, wrap angle, and width at the exit, minimum shaft power, and maximum pump efficiency will be achieved. ANOVA introduced width at the exit as the most governing parameter of pump performance characteristics.

Experimental Optimization of Using Natural Pozzolan in Chloride Ion Exposed Concrete via Taguchi Method

Concrete durability is one of the most important concerns in the field of construction. The environmentally friendly materials that can provide the durability are of great value in the construction of concrete structures. The use of natural pozzolans is one of the cheapest and most efficient methods in this field, which offers a good performance from environmental and economic point of view and satisfies required engineering parameters. In this study, the effect of using natural pozzolan in the manufacture of concrete exposed to sulfate and chloride ion of Oman sea water was investigated. The Taguchi optimization method was used to reduce the number of samples prepared, reduce the cost of experiments and achieve an optimal mix design. The four parameters, namely water to cement ratio, different percentages of natural pozzolan, super-plasticizer and cement grade with different ratios, were considered as problem variables. The Taguchi optimization method proposed 8 mix designs based on the defined levels for the variables. By constructing 96 samples, two parameters of permeability and water absorption from Oman Sea and drinking water were investigated in the samples. By introducing the results of the experiments into the Taguchi method, the final optimal design was presented by this method, and by constructing 12 additional samples and conducting permeability and water absorption experiments, the behavior of this optimal mix design was verified. The appropriate performance of the Taguchi method was demonstrated by obtaining the optimal mix designs from the Taguchi method, constructing this mix design and comparing the results with the regulation limitations. The results showed that it is acceptable to use natural pozzolan under moderate to severe chloride and sulfate ion attacks, but it is not recommended in the extreme environmental conditions.

Synthesis of Carbon Nano Materials from Carbohydrate Rich Biogenic Precursors using Chemical Vapor Deposition Method and Optimization of Parameters by Taguchi Optimization Method

Carbon Nano Materials (CNM) from biogenic carbohydrate rich non-edible precursors such as Syzygium cumini (Jamun), Tamarindus indica (Imli) and Litchi chinensis (Imli) seeds were synthesized by chemical vapour deposition method (CVD). Parameters were optimized by Taguchi optimization method, four parameters such as precursor, temperature, carrier gas and duration and three levels S. cumini, T. indica and L. chinensis as a precursor, Argon (Ar), Nitrogen (N2) and Hydrogen (H2) as a carrier gas, 1 hour (hr), 2 hours and 3 hours (hrs) for duration of pyrolysis, 800oC, 900oC and 1000oC for temperature were selected. In the present work, impact of precursor is 35.84% which is the most effective factor than temperature (29.59%) and other parameters such as duration (19.50%) and the least effective factor is carrier gas (15.07%). Impact of parameter on the yield which described by the deviation of signal to noise (S/N) ratio. The result of deviation of S/N ratio shows T. indica seed (precursor), 9000C (temperature), 2 hr (duration) and Ar (carrier gas) are the best parameters. The morphology of CNM is studied by SEM characterization and the nature of synthesized CNM by RAMAN spectroscopy.