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Schlumberger and Panasonic have announced that they will collaborate on a new battery-grade-lithium production process that they say will pave the way for improved lithium production to help meet the expected surge in demand from the fast-growing global electric vehicle (EV) market. The announcement came from the Schlumberger New Energy arm of Schlumberger and from Panasonic Energy of North America, a division of Panasonic Corporation of North America. The lithium-extraction and -production process will be used by Schlumberger at the Nevada pilot plant of its Neolith Energy venture. According to Schlumberger, Neolith Energy's approach uses a differentiated direct-lithium-extraction process to produce high-purity, battery-grade lithium material while reducing production time from more than a year to weeks. The company also said the process significantly reduces groundwater use and physical footprint vs. conventional evaporative methods of extracting lithium.
Key Takeaways Hiring companies routinely require prospective and established contractors to submit information to demonstrate their ability and likelihood of completing incident-free work. Challenges that undermine the contractor safety prequalification process are observable, however, including criteria selection, efficacy, variability and ignored criteria. This article discusses examples of nontraditional criteria that may have significant benefit for improved contractor safety prequalification. Great benefits can be realized by utilizing contractors rather than solely relying on internal resources to affect needed projects or tasks. Outsourcing allows an organization to reduce costs by maintaining a minimum workforce while allowing it to focus on its core business, promoting specialization within both the hiring and contracted company (Kozlovská & Struková, 2013; Yemenu & McCartin, 2010). Manu et al. (2013) specifically describe the benefits of contracting as including labor flexibility, transference of high-risk activities or financial risk, bargaining ability, and avoiding workers’ compensation costs. Contracting projects and services involves significant hazard and operational risk as well as benefit, however (Elliott, 2017).
The design of successful water-based aircraft requires a close collaboration between the aeronautical engineers and naval architects, who perform high-speed towing tests, stability calculations, or computational fluid dynamics in support of the design. This article presents the fundamental design considerations of waterborne aircraft, which are outside of the typical educational scope of most naval architects, but which they are sometimes asked to address. These include 1) the hydrostatic and hydrodynamic problems associated with seaplane design, 2) early-stage methods for sizing the hull, 3) prediction techniques using archival data, and 4) hydrodynamic model testing procedures. Although a new design will often require substantial iteration to achieve the desired outcome, the information in this article will assist in developing a reasonable starting point for the design spiral and provides sufficient details for a hydrodynamic model testing facility to perform a successful series of model tests on the design. Although much of the work in this field dates from the 1940s, it is important to review this material in light of the current practices being used at hydrodynamic research facilities today. A detailed description of the model testing apparatus and procedure, used in a recent study at the U.S. Naval Academy, is presented to demonstrate the current applicability of these methods and some pitfalls that can be expected in testing.
On 1 June, Hardt unveiled Europe's first hyperloop test facility on the TU Delft campus. Hardt was founded as a company by a number of the winners from Elon Musk's hyperloop competition earlier this year. Together with the European construction company BAM, they have built a test facility for this futuristic transport system. The facility consists of a tube with a length of 30 m and an external diameter of 3.2 m. It will allow testing of the systems in a vacuum at low speeds, including safety, propulsion, gliding, and the stabilization of the hyperloop vehicle.
The ro-ro passenger ship is a type of passenger ship which is commonly seen in Europe. After the tragedy of MV Estonia, an effective evaluation of escape routes in passenger ship in the initial stage of ship design has been required by International Convention for the Safety of Life at Sea (SOLAS) Convention. To reduce the loss of life in passenger ships at sea, the International Maritime Organization (IMO) has created the revised guidelines on evacuation analyses for new and existing passenger ships. This article followed IMO’s mandatory guidelines via using the hydraulic model of emergency egress to scrutinize the evacuation routes, congestion points, and the total evacuation duration of MV Tai Hwa.
ABSTRACT In order to investigate the characteristics of fluid-structure interaction(FSI) of the hydrofoil, the bi-directional FSI numerical method was developed. Based on the ANSYS software, the Large Eddy Simulation(LES) method and Finite Element Method(FEM) are combined to realize the iterative solution of fluid and structural domain. The results of vibration and pressure with and without FSI effect are compared. It is shown that when considering the FSI effect, the hydrofoil will oscillate periodically. Even if the vibration amplitude of the hydrofoil is small, it will cause the unsteady pressure fluctuation of the flow field. INTRODUCTION As the development of the ship industry, the higher performance of hydrodynamic and noise of propeller is needed. In the past, the propeller is considered rigidly during the design and the interaction between propeller and fluid is ignored. In the recent years, it is found that the interaction between propeller and fluid has much influence on the unsteady pressure in the near field and noise, so in order to designing high performance propeller the interaction between propeller and fluid can't be ignored. The fluid-structure interaction effects must be considered. The fluid structure interaction between metal structure and fluid has been studied many years in the aspect of aerodynamic. The aeroelasticity of the turbomachinery blade is studied by coupled Fluidstructure simulation(Sadeghi and Liu, 2005). A flow solver is coupled to a structural solver by use of a fluid-structure interface method. The integration of the three-dimensional unsteady Navier-Stokes equations is performed in the time domain, simultaneously to the integration of a modal three-dimensional structural model. The fluid structure interaction simulations of turbomachinery blade are studied widely (Carstens et al, 2003. Dettmer and Peric, 2006). In the aspect of underwater, the studies of fluid structure interaction are mainly forced on the flexible material. Flow-induced oscillations of a single-bladed, single-stage sewage water pump were investigated by Benra (2006) using a one-way coupling method in commercial software and data exchanged was performed via output file at interface surfaces. A coupled boundary element (BEM) and finite element (FEM) approach is developed to study the fluid-structure interaction of flexible composite propellers in subcavitating and cavitating flows (Young, 2008; Akcabay and Young, 2014). It is found that the area of the high pressure is reduced and the distribution of stress is changed when the blade is deforming. Campbell and Paterson (2011) developed and validated fluid structure interactions of an expandable impeller pump using OpenFOAM and the developed a structural solver. The commercial software is used to study the fluid-structure interaction: ANSYS CFX for fluid dynamics and ANSYS Mechanical for structural mechanics with the ANSYS MFX solver to couple both program (Schildhauer and Spille-Kohoff, 2014). The results are compared with the Turek benchmark and have good agreement. It shows the capabilities of the commercial software to solve the fluidstructure interaction problem (Hu et al, 2013. Jitendra and Frank-Hendrik, 2015. AN et al, 2017). Actually in the water, the metal propeller is easy to couple with fluid and the resonances are created (Lou and Ji, 2019). But the influence of unsteady small displacement of the metal propeller to the fluid is not very clear now. It is necessary to study the fluid structure interaction between metal propeller and fluid.
ABSTRACT In this study, the void fraction of the vapor-water mixture inside the cavitation region was experimentally investigated around NACA0012 hydrofoil in a cavitation tunnel. An optical phase detection probe was utilized to measure the void fraction inside the cloud cavitation. Two high-speed cameras were also used to obtain the side and bottom view of cavitation, in order to analyze the spatial and temporal evolution of cloud cavities. The inflow velocity was fixed to 7.5 m/s and several di erent cavitation numbers (ranging from 1.00 to 1.43) were considered for two hydrofoils with di erent chord lengths. The results of optical probe measurements indicate that the void fraction is very large (up to 40%) when the probe tip is placed within the area of sheet cavitation. Within the range of our study, the cavity length increases with decreasing cavitation number for each hydrofoil. If the relative cavity length L/c ≥ 0:4, a specific shedding frequency is obtained for each case by examining the side-view high-speed photographs. INTRODUCTION Sheet/cloud cavitation often exists in the flow around propellers and hydrofoils. The shedding and collapse of cloud cavities are the main source of undesirable phenomena, such as noise and vibration. Under certain conditions, cloud cavities are detached periodically from the hydrofoil surface, which will probably lead to highly unsteady flow and vibration (Franc and Michel, 2004). Previous research work on cloud cavitation is mainly focused on the shedding mechanism and instability analysis. Le et al. (1993) conducted a series of experiments of cavitating flow around a plano-convex hydrofoil. By adjusting the angle of attack and cavitation number, many cases were tested. Several parameters, including cavity thickness, cavity length, shedding frequency and pressure coe cient, were considered and they presented the main cavitation patterns with variable incidence angles and cavitation numbers. The shedding of cloud cavities is often attributed to two possible causes, which are re-entrant jet and bubbly shock wave. By combining experimental and numerical methods, Arndt et al. (2000) investigated the dynamical behaviors of sheet/cloud cavitation on NACA0015 hydrofoil and illustrated that shock wave was dominant in cavity shedding. Leroux et al. (2004) utilized pressure transducers to investigate the cavitation instability on NACA66. They found that both re-entrant jet and shock wave were detected in the cavitating flow and these two factors affected the cavity shedding. With the help of high-speed cameras, Che et al. (2019) illustrated the re-entrant jet played a key role in the shedding of both small- and large-scale cloud cavities by analyzing the interaction between re-entrant jet and cavity interface.
ABSTRACT Hovercraft is a kind of high-speed vehicle that glides close to the surface of the water. Due to the existence of the air cushion, tail-flick could happen to hovercraft. Tail-flick is a kind of special instability phenomenon with certain security risks, and is characterized by sudden increase in the rate of turning and the drift angle, speed decreasing, and wildly fluctuating for the angle of trim and heel, even leads to shipwreck in severe case. In this paper, a model was selected as the object of study according to some type of air cushion vehicle. The reason of tail-flick was analyzed by researching on the variation characteristic of motion parameter with the theoretical model of fourdegree-of-freedom manipulative motion. The mechanism of tail-flick has been verified and further analyzed through free running model tests. The results show that tail-flick would take place at most initial sailing speed in hovercraft, which is closely related to some factors such as sailing speed, drift angle, and angular accelerated velocity. In addition, the higher angular velocity corresponds to the smaller drift angle when tail-flick is occurring. Furthermore, the tail-flick safety zone was determined by calculation analysis. INTRODUCTION The hovercraft is characterized by small resistance, high speed, strong cross-barrier ability, therefore it has obvious advantages in military, rescue, breaking-ice, and mine sweeping (Gao, 2018; Yun, 1990; Wang, 2001). Due to the particularity of air cushion and flexible skirt, tailflick phenomenon for hovercraft easily occurs, which is unstable and leads to sudden increase of angular velocity and drift angle, and decrease of speed, and oscillation of attitude angles. Thus, deep research on this phenomenon should be carried out. The tail-flick of hovercraft is an instability phenomenon caused by interactions between water, gas and flexible skirt, closely related with the wind, wave and manipulation, which might bring a serious hazard. Given the complexity of the problem, the research by using constraint ship model experiment and theoretical method could not go far away. In addition, the experiment on real ship costs too much along with high risk, so it is necessary to adopt a self navigation model for experiment to study the tail-flick phenomenon.
Chu, Hubing (Marine Design & Research Institute of China) | Hu, Jingfeng (Marine Design & Research Institute of China) | Zhang, Haipeng (Marine Design & Research Institute of China) | Chen, Kejie (Marine Design & Research Institute of China)
ABSTRACT In order to improve the propulsion performance of air ducted propeller on a hovercraft, this paper carries out investigation of duct shape optimization. The optimization work is divided into two steps. The first step is to establish optimization method, including propulsion performance prediction method of air ducted propeller, parametric method of duct shape, automatic search and evaluation method. The numerical simulation method and a surrogate model are used to predict the propulsion performance of air ducted propeller, an improved Hicks-Henne function is adopted to change the duct shape, and the genetic algorithm is used to search and select the better schemes in the process of duct shape optimization. The second step is to optimize the duct shape with the established optimization method in the first step. The optimization result indicates that the thrust of duct is increased by 13.5% and the total thrust of air ducted propeller is increased by 2.4% compared with the original duct shape in the same state, which proves that the optimization method of this paper is suitable for duct shape optimization and the duct shape plays an important role in improving the propulsion performance of air ducted propeller. INTRODUCTION Ducted propeller refers to the propulsion system mainly consists of duct and propeller. Compared with the conventional propeller, ducted propeller has many advantages. Firstly, it can increase the flow rate around the propeller, thus delaying the flow separation of propeller and improving the propulsion performance. Secondly, the duct can generate additional thrust, thus increasing the total thrust and improving the propulsion efficiency. Thirdly, the duct weakens the strength of the vortex at the tip of the propeller and reduces the energy loss, which can also improve the propulsion efficiency. Fourthly, the duct can shield the noise generated by propeller and insure the safety of propeller when it works. Because of the above advantages, ducted propeller has been widely used in high-performance equipment such as V/STOL aircrafts (Kriebel and Mendenhall, 1966), ground effect vehicles (Tu, Wang and Shen, 2004) and hovercrafts (Lavis and Forstell, 2005).
Zou, Lu (School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University / State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University / Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai Jiao Tong University) | Zou, Zao-jian (School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University / State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University / Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai Jiao Tong University) | Xiaa, Li (School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University) | Gao, Hang (School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University)
ABSTRACT The selected static captive model tests of a cruise ship are simulated applying Computational Fluid Dynamics methods. From the virtual captive model tests, it is expected to estimate the hydrodynamic forces and moments on the cruise ship and to understand the corresponding hydrodynamic features, which will be used in determining hydrodynamic derivatives for predicting the manoeuvrability of the cruise ship. In the computations, the free surface elevation is simulated by the Volume of Fluid method, while the ship is fixed on even keel. The prescribed motions of the cruise ship during the captive model tests, such as pure drift motion, pure yaw motion, as well as combined yaw and drift motion are modeled by the Dynamic Fluid Body Interaction module. For all the tests, hydrodynamic forces and moments on the cruise ship against drift angle and/or yaw rate are predicted and discussed, and basic understandings of the physical mechanisms are also obtained from the simulated flow field. The present results are expected to obtain hydrodynamic features for predicting the manoeuvring parameters of the cruise ship and to provide useful guidance of selecting the motion variables and dimensions of the facility for the captive model tests. INTRODUCTION A cruise ship is a large and specific passenger ship, which is capable of carrying thousands of passengers and normally equipped with a pair of podded propellers as both propulsion and control devices. With the rapid increase of demands in pleasure sea voyage, the number of cruise ships worldwide has progressively grown in the past two decades. As one of the most important hydrodynamic performances of a ship, the manoeuvrability should be carefully assessed at the design stage. However, the study or literature on the manoeuvring prediction of cruise ships is still limited due to the particularity of their hull form (Woodward et al., 2009). To obtain appropriate predictions of the manoeuvrability of a cruise ship, several approaches can be used referring to the benchmark procedures based on the methods recommended by the International Towing Tank Conference (ITTC, 2017a) and the Workshop on Verification and Validation of Ship Manoeuvring Simulation Methods (SIMMAN, 2008 and 2014). In general, the prediction can be made either directly through free running model tests (Carrica et al., 2013; Wang et al., 2017) with rotating propeller(s) and steering rudder(s), or by captive model tests (Yasukawa and Yoshimura, 2015; Guo and Zou, 2017; Liu et al., 2018) where the hydrodynamic forces and moments of prescribed (static or dynamic) ship motions are obtained experimentally or numerically, and then used in the mathematical model for predicting manoeuvrability. The latter is believed to be more economical and reliable one in practical application (SIMMAN, 2008 and 2014). The static captive model tests include the rudder force test in straight or oblique motion, oblique towing test with constant drift angle, the circular motion test with steady yaw rate, etc.; while the dynamic captive model test mainly consider the kinematic motion parameters, such as the harmonic sway motion, yaw motion, combined sway and yaw motion, combined drift and yaw motion, etc. From different tests, the linear and nonlinear hydrodynamic coefficients of the ship to set up the manoeuvring mathematical model are obtained.