An Integrated Probability-Based Propulsor-Hull Matching Methodology

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
Matthew R. Kramer ◽  
Michael R. Motley ◽  
Yin L. Young
Keyword(s):  
Structural Integrity ◽  
Surface Effect ◽  
Weighting Function ◽  
Full Range ◽  
Joint Probability ◽  
Design Procedure ◽  
Optimal Solution ◽  
Operating Conditions ◽  
Operational Space ◽  
Surface Effect Ship

Traditionally, designers of marine propulsors select a discrete number of critical design points for which to optimize the propulsor geometry. The design procedure carefully weighs the needs to be fuel efficient, to minimize cavitation, to maintain structural integrity, and to provide enough thrust to reach the desired speed, including the need to overcome any resistance humps. The current work proposes a new, alternative propulsor-hull matching methodology that is able to systematically consider the full range of expected operating conditions. A joint probability density function is used to represent the probabilistic operational space as a function of ship speed and sea state, and is used as a weighting function to select the propulsor that will minimize the annual fuel consumption while satisfying a set of constraints. The new probabilistic design approach is able to automatically locate the globally optimal solution by considering the probability of occurrence along with system performance characteristics. Hence, it is able to avoid the inherent ambiguity of selecting the proper design points. The proposed methodology is general to the design of marine propulsors for any type of vessel and engine system. It is applied in the current study for the sizing of waterjets for a surface effect ship.

Flexibility of Seakeeping Simulation Tools for Landing Craft Hullforms

2017 ◽  
Author(s):  
Kevin Silva ◽  
Andrew Silver ◽  
Kenneth Weems ◽  
David Wundrow ◽  
Sheguang Zhang
Keyword(s):  
Surface Effect ◽  
Water Jet ◽  
Operating Conditions ◽  
Physical Models ◽  
Simulation Tools ◽  
Test Conditions ◽  
Seakeeping Performance ◽  
Surface Effect Ship ◽  
Analytical Tools ◽  
Large Amplitude Motion

As the operational requirements of landing craft expand to faster speeds and higher sea states, more complex hullforms are being proposed to meet these requirements. The seakeeping performance of such vessels can become difficult to predict. Analytical tools must be flexible in order to handle the variety of operating conditions, hull geometries, loading conditions, and other attributes. The analytical seakeeping models should be based on the physical models of the hydrodynamic phenomena rather than case-specific empirical tuning. This paper describes a study that evaluated the ability of the Large Amplitude Motion Program (LAMP) to simulate traditional and non-traditional landing craft hullforms in varying operating conditions. The hullforms include a traditional semi-planing monohull, a semi-planing water jet propelled “W” shaped hull, a water jet propelled catamaran, and a catamaran Surface Effect Ship (SES) style hull. The measures taken to model each hullform and test conditions in LAMP are discussed and the correlation between experimental data and LAMP predictions are presented through comparisons of motions and accelerations.

Ethanol Steam Reforming for Hydrogen Production in Microchannel Reactors: Experimental Design and Optimization

2013 ◽  
Vol 11 (1) ◽  
pp. 9-17 ◽  
Author(s):  
Aulus Bineli ◽  
Jules Thibault ◽  
André Jardini ◽  
Rubens Maciel Filho
Keyword(s):  
Experimental Design ◽  
Reaction Kinetics ◽  
Design Procedure ◽  
Optimal Solution ◽  
Operating Conditions ◽  
Design And Optimization ◽  
Microchannel Reactors ◽  
Decision Variables ◽  
Operating Region ◽  
Prior Literature

Abstract In this investigation, an experimental design procedure using prior literature information has been used to guide the localization of optimal points for reaction kinetics study. Three kinetic models were identified and the Pareto domain was circumscribed for a set of three decision variables and two objective functions to find an optimal solution. From the range of Pareto-optimal solutions obtained, the kinetic model considered to be the most reliable was used to explore the optimal operating region. Finally, the experimental design points were chosen to ensure a sufficient range of operating conditions to identify the reaction kinetics.

The behaviour of heavily loaded line contacts with transverse roughness

1999 ◽  
Vol 213 (4) ◽  
pp. 309-320 ◽  
Author(s):  
C. J. Hooke
Keyword(s):  
Surface Roughness ◽  
Full Range ◽  
Numerical Results ◽  
Operating Conditions ◽  
Entrainment Velocity ◽  
Original Surface ◽  
Line Contacts ◽  
Transverse Roughness ◽  
Inlet Length

In heavily loaded, piezoviscous contacts the surface roughness tends to be flattened inside the conjunction by any relative sliding of the surfaces. However, before it is flattened, the roughness affects the inlet to the contact, producing clearance variations there. These variations are then convected through the contact, at the entrainment velocity, producing a clearance distribution that differs from the original surface. The present paper explores this behaviour and establishes how the amplitude of the convected clearance varies with wavelength and operating conditions. It is shown that the primary influence is the ratio of the wavelength to the inlet length of the conjunction. Where this ratio is large, the roughness is smoothed and there is little variation in clearance under the conjunction. Where the ratio is small, significant variations in clearance may occur but the precise amplitude and phasing depend on the ratio of slide to roll velocities and on the value of a piezoviscous parameter, c. The numerical results agree closely with existing solutions but extend these to cover the full range of operating conditions.

scholarly journals Mode I Crack Propagation Experimental Analysis of Adhesive Bonded Joints Comprising Glass Fibre Composite Material under Impact and Constant Amplitude Fatigue Loading

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4380
Author(s):  
Alirio Andres Bautista Villamil ◽  
Juan Pablo Casas Rodriguez ◽  
Alicia Porras Holguin ◽  
Maribel Silva Barrera
Keyword(s):  
Crack Propagation ◽  
Structural Integrity ◽  
Crack Propagation Rate ◽  
Fatigue Loading ◽  
Propagation Rate ◽  
Operating Conditions ◽  
Impact Testing ◽  
Mode I ◽  
Mode I Crack ◽  
Constant Amplitude

The T-90 Calima is a low-wing monoplane aircraft. Its structure is mainly composed of different components of composite materials, which are mainly bonded by using adhesive joints of different thicknesses. The T-90 Calima is a trainer aircraft; thus, adverse operating conditions such as hard landings, which cause impact loads, may affect the structural integrity of aircrafts. As a result, in this study, the mode I crack propagation rate of a typical adhesive joint of the aircraft is estimated under impact and constant amplitude fatigue loading. To this end, effects of adhesive thickness on the mechanical performance of the joint under quasistatic loading conditions, impact and constant amplitude fatigue in double cantilever beam (DCB) specimens are experimentally investigated. Cyclic impact is induced using a drop-weight impact testing machine to obtain the crack propagation rate (da/dN) as a function of the maximum strain energy release rate (GImax) diagram; likewise, this diagram is also obtained under constant amplitude fatigue, and both diagrams are compared to determine the effect of each type of loading on the structural integrity of the joint. Results reveal that the crack propagation rate under impact fatigue is three orders of magnitude greater than that under constant amplitude fatigue.

A Simple Design Approach for Excitation Controller and Power System Stabilizer

2010 ◽  
Author(s):  
G. Fusco ◽  
M. Russo
Keyword(s):  
Power System ◽  
Transient Stability ◽  
Short Circuit ◽  
Design Procedure ◽  
Voltage Regulation ◽  
Operating Conditions ◽  
Power System Stabilizer ◽  
Simple Design ◽  
Wide Range ◽  
System Stabilizer

This paper proposes a simple design procedure to solve the problem of controlling generator transient stability following large disturbances in power systems. A state-feedback excitation controller and power system stabilizer are designed to guarantee robustness against uncertainty in the system parameters. These controllers ensure satisfactory swing damping and quick decay of the voltage regulation error over a wide range of operating conditions. The controller performance is evaluated in a case study in which a three-phase short-circuit fault near the generator terminals in a four-bus power system is simulated.

Large Surface Effect Ship Size Limits

2013 ◽  
Vol 29 (02) ◽  
pp. 84-91
Author(s):  
Stefanos Koullias ◽  
Santiago Balestrini Robinson ◽  
Dimitri N. Mavris
Keyword(s):  
Historical Data ◽  
Surface Effect ◽  
Advanced Materials ◽  
Complex Structures ◽  
First Principle ◽  
Simplified Models ◽  
Surface Effect Ship ◽  
Size Limits ◽  
Technology Level ◽  
Insight Into

The purpose of this study is to obtain insight into surface effect ship (SES) endurance without reliance on historical data as a function of geometry, displacement, and technology level. First-principle models of the resistance, structures, and propulsion system are developed and integrated to predict large SES endurance and to suggest the directions that future large SESs will take. It is found that large SESs are dominated by structural weight, which indicates the need for advanced materials and complex structures, and that advanced propulsion cycles can increase endurance by up to 33%. SES endurance is shown to be a nonlinear discontinuous function of geometry, displacement, and technology level that cannot be predicted by simplified models or assumptions.

Optimum Structural Design of High-Speed Surface Effect Ships Built of Composite Materials

2003 ◽  
Vol 40 (01) ◽  
pp. 42-48
Author(s):  
Chang Doo Jang ◽  
Ho Kyung Kim ◽  
Ha Cheol Song
Keyword(s):  
Composite Materials ◽  
Computer Program ◽  
Structural Design ◽  
High Speed ◽  
Surface Effect ◽  
Minimum Weight ◽  
Original Design ◽  
Optimum Structural Design ◽  
Surface Effect Ship ◽  
Speed Performance

A surface effect ship is known to be comparable to a high-speed ship. For the structural design of surface effect ships, advanced design methods are needed which can reflect the various loading conditions different from those of conventional ships. Also, minimum weight design is essential because hull weight significantly affects the lift, thrust powering and high-speed performance. This paper presents the procedure of optimum structural design and a computer program to minimize the hull weight of surface effect ships built of composite materials. By using the developed computer program, the optimum structural designs for three types of surface effect ships—built of sandwich plate only, stiffened single skin plate only, and both plates—are carried out and the efficiency of each type is investigated in terms of weight. The computer program, developed herein, successfully reduced the hull weight of surface effect ships by 15–30% compared with the original design. Numerical results of optimum structural designs are presented and discussed.

scholarly journals Sensitivity of Supersonic ORC Turbine Injector Designs to Fluctuating Operating Conditions

2015 ◽  
Author(s):  
Elio A. Bufi ◽  
Paola Cinnella ◽  
Xavier Merle
Keyword(s):  
Method Of Characteristics ◽  
Organic Rankine Cycle ◽  
Design Procedure ◽  
Rankine Cycle ◽  
Operating Conditions ◽  
Real Gas ◽  
Real Gas Effects ◽  
Nozzle Shape ◽  
Turbine Design ◽  
The Impact

The design of an efficient organic rankine cycle (ORC) expander needs to take properly into account strong real gas effects that may occur in given ranges of operating conditions, which can also be highly variable. In this work, we first design ORC turbine geometries by means of a fast 2-D design procedure based on the method of characteristics (MOC) for supersonic nozzles characterized by strong real gas effects. Thanks to a geometric post-processing procedure, the resulting nozzle shape is then adapted to generate an axial ORC blade vane geometry. Subsequently, the impact of uncertain operating conditions on turbine design is investigated by coupling the MOC algorithm with a Probabilistic Collocation Method (PCM) algorithm. Besides, the injector geometry generated at nominal operating conditions is simulated by means of an in-house CFD solver. The code is coupled to the PCM algorithm and a performance sensitivity analysis, in terms of adiabatic efficiency and power output, to variations of the operating conditions is carried out.

scholarly journals Aero-Thermal Design and Testing of Advanced Turbine Blades

1997 ◽  
Author(s):  
M. Haendler ◽  
D. Raake ◽  
M. Scheurlen
Keyword(s):  
Gas Turbines ◽  
Full Range ◽  
Turbine Blades ◽  
Design Procedure ◽  
Thermal Design ◽  
Test Facility ◽  
Optical Pyrometer ◽  
Electrical Systems ◽  
Operation Conditions ◽  
Improved Performance

Based on the experience gained with more than 80 machines operating worldwide in 50 and 60 Hz electrical systems respectively, Siemens has developed a new generation of advanced gas turbines which yield substantially improved performance at a higher output level. This “3A-Series” comprises three gas turbine models ranging from 70 MW to 240 MW for 50 Hz and 60 Hz power generation applications. The first of the new advanced gas turbines with 170 MW and 3600 rpm was tested in the Berlin factory test facility under the full range of operation conditions. It was equipped with various measurement systems to monitor pressures, gas and metal temperatures, clearances, strains, vibrations and exhaust emissions. This paper presents the aero-thermal design procedure of the highly thermal loaded film cooled first stage blading. The predictions are compared with the extensive optical pyrometer measurements taken at the Siemens test facility on the V84.3A machine under full load conditions. The pyrometer was inserted at several locations in the turbine and radially moved giving a complete surface temperature information of the first stage vanes and blades.

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