Impact of RCS- Cross Root Process and die design in Commercial Brass Alloy Sheets

Commercial Brass Alloy Sheet are subjected to intense plastic deformation using RCS method to improvise its metallurgical / Mechanical properties. The impact of Repeated Corrugation and Straightening Process for a number of cycles using two different type of dies on hardness, homogeneity and grain structure in commercial Brass Alloy Sheet at room temperature is evaluated experimentally. Two types of V-grove corrugation dies (flat groove corrugated, and semi-circular grooved corrugated ) and flattening dies were used in this work with a pressing velocity of 1mm/min. The modus operandi involves repeated and controlled corrugation followed by straightening for a number of cycles. In the process the brass sheets are made to undergo intense plastic deformation by repeated shearing using first flat groove corrugated dies followed by flattening of sheets using flat dies and in the second setup, semi-circular groove corrugated dies are used, followed by flattening of sheets using flat dies. In the samples processed using flat groove corrugated dies, the BHN increases from 95.47 to 234.34 upto 4th cycles and then decreased to 218.63 in the 5th cycle experimentally. In the samples processed using semi-circular groove corrugated dies, the BHN increases from 95.47 to 202.02 upto 4th cycle and then decreases to 194 for 5th cycle experimentally. The results of simulation studies done using the simulation software (AFDEX) are in consonance with the experimental results. Simulation analysis done to study the behavior of commercial Brass Alloy Sheet subjected to plastic deformation using Semi-circular groove corrugated dies shows that the effective strain has increased from 0.6442 for the 1st cycle to 2.94 at the end of 5th cycle, and for the flat grooved corrugated dies the effective strain increases from 1.17 for the 1st cycle to 6.21 at the end of 5th cycle. This RCS process can be used for bulk production of sheets with high hardness, fine grain structure and smoother surface.

Effect of Bionic Groove Surface Blade on Cavitation Characteristics of Centrifugal Pump

In order to improve the cavitation resistance of centrifugal pump, bionic groove surface structure was arranged on the suction surface of centrifugal pump blade which is the most prone to cavitation. Numerical simulation method was used to study the influence of different-shape groove blade on cavitation performance of centrifugal pump. The results showed that the head and efficiency of the centrifugal pump with circular grooved surface blades were close to the smooth surface blade centrifugal pump and higher than those with triangular grooved surface blades and rectangular grooved surface blades. The low pressure area of the circular groove blade was the smallest and the cavitation resistance was the best. At the critical cavitation margin point, circular groove blade can effectively reduce the probability of negative incidence, and the cavitation inhibition effect was the most obvious.

Numerical Simulation for Heat Transfer of Nanofluid in a Rotating Circular Groove Using a Continuous Finite Element Scheme

In this paper, we investigate the heat transfer of the power-law-fluids-based nanofluids in a rotating circular groove. The circular groove rotates with a constant speed and the temperature on the wall of the groove is different from the temperature inside in the initial time. The effects of thermophoresis and Brownian are considered. The thermal conductivity of the nanofluids is taken as a constant. We solve the model with the finite element method directly and discretize them using a continuous finite element scheme in space and a modified midpoint scheme in time. From the results we can find that the heat transfer enhancement of the nanofluids increases as the power law index of the base fluid decreases.

Leakage and Rotordynamics Numerical Study of Circular Grooved and Rectangular Grooved Labyrinth Seals

Labyrinth seals are used in many turbomachines to reduce the leakage from high to low pressure zones. In this paper, a new labyrinth seal design with a circular groove is presented. A 2D CFD simulation was used to model the leakage and optimize the tooth thickness of the new design and compare it to the traditional labyrinth seals with a rectangular groove. The rotordynamics coefficients for the new circular groove design as well as the traditional rectangular groove design were computed using 3D CFD simulations. The results show that the new proposed design provides less leakage than the traditional rectangular groove design. Moreover the new design provides more direct damping when compared to the traditional rectangular labyrinth seal.