A Practical Approach for Design of Marine Propellers with Systematic Propeller Series
Original scientific paper Although there have been important developments in marine propellers since their first use in 1850, the main concept has been conserved. Parallel to the developments in the computer technologies in the past 50 years, methods based on the circulation theory are often used for the design and analysis of propellers. Due to the ability to predict the propulsion performance with just a few design parameters, the use of systematic propeller series based on open water model experiments is still widespread. The design with standard propeller series is usually made with diagrams developed from model experiments. Reading errors during the use of these diagrams are inevitable. In the presented study a practical approach is developed for preventing reading errors and time loss during the design with standard propeller series. A practical approach based on empirical formulas for the design and performance prediction for four-bladed Wageningen B propeller series is presented, and design applications for three propellers with different loading conditions are realized. The results obtained from the presented method are compared with those of open water diagram data and a good agreement between the results is observed.
Static and Rrotordynamic Analysis of Composite Blade Marine Propeller
This project work deals with modelling and analysing the propeller blade of a marine vehicle for their strength. A propeller is a complex geometry which requires high end modelling software. The solid model of propeller is developed by using Solidwork 2014 & Matlab R12.The meshing is generated for the model using Ansys. Static and rotordynamic analysis of composite blade propeller is carried out in ANSYS 14.5 software. The stresses obtained are well within the limit of anisotropic property of the materials. The deflection for composite blade propeller is determined. Optimal solution was found by using TAGUCHI method. The critical speed of the propeller is determined using rotordynamic. On comparison which shows that by changing different parameters like speed of shaft and pressure of water on propeller we found optimum solution for the design of propeller.
Experimental study on ground vibration of blasting the boulder with tandem shaped charging warhead
Hazardous effects of blasting the boulder with the new breaking-blasting equipment-tandem shaped charging warhead are mainly air shock wave, seismic wave and blast slung shot. Blast-induced ground vibration is one of the inevitable effects and may cause substantial damage to nearby structures. Started from the formation process and mechanism of ground vibration to study the seismic wave, the research attained curve of vibration velocity of monitoring points by TC-4850 and carried out differential and fast Fourier transform analysis of the curve. And the results concluded that blasting vibration with tandem shaped charging warhead mainly comes from prime charge; the attenuation law can be predicted by Sadev’s Formula. Explosion vibration frequency range is 20-150 Hz, while with the increase of distance from the blasting center, blasting vibration intensity attenuates rapidly, vibration duration increases and vibration frequency gradually reduces. Compared with general rock blasting, its attenuation rate of blasting vibration is faster with higher frequency and smaller impact on buildings, but the harm effects should not be ignored for the special application environment.