A Comparison of Waterproof Motor Housings for Student Robotics Teams

Professionals and students alike create high-performance Remotely Operated Vehicles (ROV)s to complete a multitude of tasks underwater. The student ROV competition created by Marine Advanced Technology Education (MATE) simulates the tasks faced by the modern professional underwater robotics industry. Students often design their ROVs with techniques used by the professional underwater robotics industry. Unlike professionals, students do not have many resources comparing manufacturable ROV components that fit within their design restrictions. Without information about components that they choose to use on their ROVs, students might miss an opportunity to implement a better alternative technology. Such is the case with older Shaft Sealed Housings (SSH) and less common Magnetically Coupled Housings (MCH). In this paper, essential aspects of both alternative designs for waterproof motor housings are tested to determine overall performance. The waterproofness of each housing is tested experimentally over long periods of time in an environment simulating the most extreme depths experienced at the MATE ROV Competition. Maximum static torque is measured on a torque sensor. Cost and manufacturability of each housing are recorded in tables. Ultimately, student robotics teams are left to determine which motor housing best fits their design requirements, based on the data discovered and presented in this paper.

Experimental Study Wind Turbine Performance of Straight-Savonius and Ice-Wind Type on the Similar proportion Aspect Ratio

The Performance of wind turbines at low speed can be improved by Ice-Wind model, particularly in self-starting conditions. Compared to a traditional wind turbine with two blades of the similar area and material, Ice-Wind can increase efficiency by 19%. Research on the Savonius turbine, particularly the Ice-Wind turbine, is challenging. It is because it has many restrictive parameters, such as the height, diameter, and area of the turbine blades. The Ice-Wind turbine shape is obtained by cutting a Savonius turbine. This process led to research on Ice-Wind turbines only under the similar parameters. The aspect ratio of a Savonius turbine has a significant effect on the speed, mechanical power and static-torque produced by the wind turbine. The research was done on Savonius and Ice-Wind turbines with the similar aspect ratio. The results show that the speed, power factor and efficiency of the Savonius turbine are higher than those of Ice-Wind. However, Savonius produces a smaller static-torque coefficient value than Ice-Wind. The results of this research contrast with other studies comparing Savonius and Ice-Wind turbines. In other researches, Savonius and Ice-Wind turbines have the similar area but different aspect ratios.

Numerical Simulation and Wind Tunnel Investigation on Static Characteristics of VAWT Rotor Starter with Lift-Drag Combined Structure

In order to get rid of the impact of the global financial crisis and actively respond to global climate change, it has become a common choice for global economic development to develop clean energy such as wind energy, improve energy efficiency and reduce greenhouse gas emissions. With the advantages of simple structure, unnecessary facing the wind direction, and unique appearance, the vertical axis wind turbine (VAWT) attracts extensive attention in the field of small and medium wind turbines. The lift-type VAWT exhibits outstanding aerodynamic characteristics at a high tip speed ratio, while the starting characteristics are generally undesirable at a low wind speed; thus, how to improve the starting characteristics of the lift-type VAWT has always been an important issue. In this paper, a lift-drag combined starter (LDCS) suitable for lift-type VAWT was proposed to optimize the starting characteristics of lift-type VAWT. With semi-elliptical drag blades and lift blades equipped on the middle and rear part outside the starter, the structure is characterized by lift-drag combination, weakening the adverse effect of the starter with semi-elliptical drag blades alone on the output performance of the original lift-type VAWT and improving the characteristics of the lift-drag combined VAWT. The static characteristic is one of the important starting characteristics of the wind turbine. The rapid development of computational fluid dynamics has laid a solid material foundation for VAWT. Thus the static characteristics of the LDCS with different numbers of blades were investigated by conducting numerical simulation and wind tunnel tests. The results demonstrated that the static torque coefficient of LDCS increased significantly with the increased incoming wind speed. The average value of the static torque coefficient also increased significantly. This study can provide guidelines for the research of lift-drag combined wind turbines.

Performance comparison of axial-flux switched reluctance machines with non-oriented and grain-oriented electrical steel rotors

This paper studies the performance of an axial-flux switched reluctance machine (AFSRM) using GOES (grain-oriented electrical steel) in its rotor and comparing it to a NOES (non-oriented electrical steel) rotor. Indeed, the AFSRM structure lends itself well to the use of GOES, especially at the rotor. In order to evaluate the intrinsic capabilities of the AFSRM, self-inductance versus rotor position and static torque were numerically simulated at a given operating point and used as indicators for the NOES and GOES performance comparison. The static torque is also used to determine and compare the torque per volume ratios and grasp the impact of GOES use in a 3D rotating structure. The introduction of GOES in a rotating machine leads to an improvement of the electromagnetic torque mean and maximum values, allowing to evaluate the GOES impact on the machine performance.

Improvement of Aerodynamic Performance of Savonius Wind Rotor Using Straight-Arc Curtain

A straight and an arc-shaped curtain are combined to enhance the aerodynamic performance of the Savonius wind rotor. The straight-arc curtain is placed in front of the Savonius wind rotor to reduce the negative moment on the convex blade and increase the positive moment on the concave blade. The static and dynamic performances of the Savonius wind rotor with and without the curtain are investigated based on the computational fluid dynamics method. The results show that the static torque is higher with the curtain than without it at the same angle-of-attack. The maximum mean power coefficient with the curtain is increased by about 50% compared with conventional Savonius wind rotor. Additionally, the flow field around the rotor with the straight-arc curtain is presented, and the flow control mechanics of the straight-arc curtain are discussed.

Design and 3D CFD Static Performance Study of a Two-Blade IceWind Turbine

The IceWind turbine, a new type of Vertical Axis Wind Turbine, was proposed by an Iceland based startup. It is a product that has been featured in few published scientific research studies. This paper investigates the IceWind turbine’s performance numerically. Three-dimensional numerical simulations are conducted for the full scale model using the SST K-ω model at a wind speed of 15.8 m/s. The following results are documented: static torque, velocity distributions and streamlines, and pressure distribution. Comparisons with previous data are established. Additionally, comparisons with the Savonius wind turbine in the same swept area are conducted to determine how efficient the new type of turbine is. The IceWind turbine shows a similar level of performance with slightly higher static torque values. Vortices behind the IceWind turbine are confirmed to be three-dimensional and are larger than those of Savonius turbine.