Remotely Operated Underwater Vehicles (ROV) currently have been utilized for scientific and commercial applications. Many industries are involved in developing robots in order to reduce human effort as well as increase productivity, efficiency, and monitoring. That said, the need to optimize the cost for design of ROVs became popular. In the present work, a simplified design procedure of a low cost-light-weight ROV is proposed. The design overview includes a description of the three thrusters operated by bilge pump electric motors. The ROV contains only a camera, an IMU and a GPS sensor. The ROV is wired to a control station that is equipped with a screen with a GUI, a joystick and a keyboard to monitor and control the ROV. The design is optimized to achieve a neutral buoyancy force in order to reduce the stabilizing effort during operation, hence reducing energy consumption. The drag force, lift force, drag center, lift center and fluid velocity contours are predicted using a CFD tool. Dynamic analysis including thrust and drag forces in longitudinal, vertical and yaw directions of motion are investigated to facilitate selection of the prime movers. Finally, the control strategy and electrical system description is presented. The proposed methodology proved that a satisfactory performance with an optimized design is achievable. The ROV design presented could be used in quick and low cost inspection of ships.

Energy consumption of machine tools needs to be investigated and decomposed to determine areas for improvement. Motors are one key area of energy consumption, and the analysis of motors, including pump motors is useful for long term energy saving. The following paper describes the static and dynamic analysis of a machine tool stand and an energy analysis to compare manufacturing the stand against using the pump motor. The stand needed to be designed that would both withstand the static load of the machine and minimize vibrational excitation caused during grinding experiments. A review of life cycle inventories for induction motors was then undertaken to evaluate the manufacturing energy consumption of pump motors. A breakeven time was determined for the energy investment of replacing a coolant pump with a stand to conserve energy via gravity-fed coolant recirculation. The simulations were performed as worst-case scenarios and are not necessarily indicative of regular use. Results indicate that the stand as designed will not transmit any significant harmonic vibrations. Results of the energy comparison identify that fractional horsepower coolant pumps operating continuously can be replaced with a stand and the energy to produce the stand will break even within two to three years depending on operating schedule.

The planar rotary mechanism, by virtue of its volume changing ability can be used as a pump, engine or compressor. Most of the types of rotary mechanisms used today, from the Wankel rotary engine to the gerotor pump, are based on epitrochoidal generation and its conjugate shape. This paper presents the mathematical relationships for the hypotrochoidal generation and also compares the flow rate, pocket and pump displacement between the hypotrochoidal and epitrochoidal generated profiles.

The stability of the typical rotating fluid machineries such as the single-stage and multi-stage pumps which consist of impellers, bearings and noncontacting seals is evaluated from the viewpoint of seals. The individual contribution of the impeller, bearing as well as seal to the stability, and the dynamic interactions of these fluid elements are investigated. In the investigation, some types of bearings, and seals such as annular smooth seals, parallel grooved seals and damper seals are compared to seek the better ones for the rotor stability. The effect of working conditions on the stability is also investigated. The results show that the rotor stability is strongly affected by the characteristics of these fluid elements, and the stability can be improved by changing the unstable fluid element.

Modern turbomachinery is used to provide power for a wide range of applications, from steam turbines for electrical power plants to the turbopumps used in the Space Shuttle Main Engine. Such devices are subject to a variety of dynamical problems, including vibration, rotordynamical instability, and shaft whirl. In order to properly design and evaluate the performance and stability of turbomachinery, It is important that appropriate analytical tools be available that allow for the study of potentially important dynamical effects. This research effort is concerned with developing a procedure to account for disk flexibility which can readily be used for investigating how such effects might influence the natural frequencies and critical speeds of practical rotor systems. In the present work, a transfer matrix procedure is developed in which the disk flexibility effects are accounted for by means of additional terms included in the transfer matrix formulation. In this development, the shaft is treated as a discrete system while the disk is modelled as a continuous system using the governing partial differential equation. Based on this governing equation, an equivalent inertial moment M k * , which is the generalized dynamic force coupling between shaft and disk, is then derived. Analysis shows that only the disk modes of one nodal diameter contribute to the inertial moment, M k * , and thus influence the natural frequencies of the rotor system. To determine the M k * , the modal expansion method is employed and the governing partial differential equation of the disk is transformed to a set of decoupled forced vibration equations in the generalized coordinates. The M k * are then calculated in terms of modal shapes, natural frequencies, and material and geometric parameters which can be found in the literature or can be obtained from experiments. Finally the M k * are incorporated into the point transfer matrix. By so doing, the properties of quick computational speed and ease of use are retained and the complexity of solving partial differential equations is avoided. This allows the present procedure to be easily applied to practical engineering problems. This is especially true for multiple flexible disk rotor systems. As an example, three different cases for a simplified model of the Space Shuttle Main Engine (SSME) High Pressure Oxygen Turbo-Pump (HPOTP) rotor have been studied using this procedure. Some of the more interesting results obtained in this example study are enumerated below. 1.) Disk flexibility can introduce additional natural frequency(s) to a rotor system. 2.) Disk flexibility can cause shifting of some of the natural frequencies. 3.) As disk flexibility is increased, lower natural frequencies of the rotor system will be influenced. 4.) At certain rotor speeds, disk flexibility may cause the disappearance of a natural frequency. 5.) The axial position of the disk on the rotor shaft has a significant effect on the degree of this influence.

A mathematical model of the power transmission through a Van Doorne steel belt continuously variable transmission is developed. The approach is based on a simplified viscous oil shear stress model. This enables the determination of the power transmission loss resulting from shearing the oil film along the traction line. The power to maintain the necessary hydraulic clamping forces is taken into account to optimise the power transmission efficiency. The analytical solution is evaluated numerically and compared with experimental results. Variations in the hydraulic pump displacement that is determined by the required ratio adjustment dynamics show that with a sufficiently small pump, peak efficiencies exceeding 97% are possible.

Stepless vehicle drives will assume their place next to automatic switching units throughout the world if they meet their expected fuel-saving potential. This necessitates optimizing the individual components of the CVT as regards their efficiency. The main source of losses are the hydraulic supply units and the losses which result specifically from non-positive transmission. In the case of stepless chain conveners, these result mainly from friction disk deformation. These losses account for 50 to 70 % of total CVT losses. Both loss components are influenced by the lubricant to a significantly greater extent than it would appear at first sight: In the case of fully-hydraulic clamping and control systems, the viscosity and its long-term stability determines the degree of leakage losses and therefore the size of the pump or pump combinations. This applies to pressure levels between 20 and 40 bar. This in turn is directly proportional to the hydraulic losses on the CVT. The friction coefficient of the lubricant determines the level of the necessary clamping forces. These are responsible for friction-disk deformation. Also of importance as far as the selection of lubricant is concerned is its influence on the CVT service life. The critical service life limits for chain converters are chain breakage (not the subject of this report) and evidence of wear, i.e. grey staining, sheave-grooving, pitting, scoring and rocker pin wear. Standardized test methods exist at P.I.V. for both wear manifestations and for the friction coefficient, these tests allowing a targeted selection of lubricants.

In a previous paper the author proposed a method to reduce the periodic variation in flow rate for an external gear pump. To verify the experimental results, a series of experimental tests on a expressly realized gear pump, was carried out. The pump was equipped with relieving grooves milled into the side plates. The tests were done on a closed piping specifically realized and equipped for measuring the instantaneous flow rate of the fluid through a wedge-shaped hot film probe.

Flexible Computer Integrated Manufacturing (FCIM) technology existing today in industry, combined with modern repair processes, can be used to address erosion and corrosion inherent in submarine and surface ship fluid systems. Commander Submarine Force Atlantic Fleet (COMSUBLANT) will implement in the near future a Pump and Valve Repair System in the Trident Refit Facility (TRF), Submarine Base, Kings Bay, Georgia. The system will support the repair of submarine and surface ship components such as valve bodies, valve tailpieces, and pump casings. It will replace metal lost by erosion and corrosion using repair processes such as automated welding and epoxy spray and reliably return these components to original specification with computer numerical control (CNC) machining.

A Finite Element Analysis (FEA) parametric study of 2D Magnetohydrodynamic (MHD) pump flow is presented. The analysis assumes steady, viscous, incompressible fluid flow in the presence of a magnetic field applied normal to the plane of motion. The fluid is electrically conducting and the analysis is applicable to the design and performance evaluation of DC electromagnetic MHD pumps. The primitive variable Galerkin finite element approach is used to discretize the complete Navier-Stokes equations governing fluid motion which are coupled to both the Maxwell’s equations governing electromagnetic fields, and the conservation of energy equation governing the temperature field. Analysis variables include: velocity; pressure; temperature; voltage; electric field; magnetic flux; current density and pump efficiency. These variables are evaluated for low to moderate values of the magnetic interactive parameter. The velocity field distortion is compared to other numerical results and insight into solution convergence difficulties is presented.

This paper analyses a particular type of rotary positive-displacement pumps with lobes having epitrochoidal flanks, whose distinctive feature is that of providing a strictly constant geometric instantaneous flow rate. The pump design is analysed from geometric and kinematical points of view. Then the behavior of this type of lobe pump is compared with that of involute gear pumps.

Hydraulic lash adjusters can eliminate clearance between components in the automotive valve trains. A two-mode dynamic model for the adjuster is derived by including check valve motions at two operating modes. The oil refill mechanism controlled by the check valve is experimentally identified. The oil compressibility in the oil chamber and the oil leakage through the annular gap between the plunger and the body are also considered. It is shown that motion of the adjuster plunger must satisfy a third-order, non-linear differential equation of motion. The differential equation is numerically integrated, and the experimental data in leak-down test provided by the manufacturer is shown to be in good agreement with the model. The annular gap is found to be the key factor in controlling leak-down speed, and the effective orifice diameter is shown to be the key factor in describing the pump-up phenomenon. It is also found that one percent air entrainment in the oil chamber of the adjuster seriously compromises overall adjuster rigidity and reduces the natural frequency of the adjuster almost 50 percent.

The generation and design of cycloidal (trochoidal) gearing that have found application in Wankel engines, and Root’s blowers and pumps are considered. The following topics will be covered: (i) the generation and geometry of planar cycloidal gearing and rotors of screw Root’s blowers, and (ii) an improved design that avoids profile and surface singularities. Computer programs have been developed that support the proposed analytical solutions. The developed theory is illustrated with examples.

Presently used balancing methods for multicylinder engines and pumps are for partial balancing. As a result the complete shaking force, shaking torque, and shaking moment balancings of engines require the use of harmonic force and harmonic torque and moment balancers. This article presents a new method for complete shaking force and shaking moment balancing of multicylinder engines that requires no harmonic balancers. This is achieved by keeping the total center of mass of each slider crank loop stationary, where the design equations are developed using a linearly independent mass vector method. Balancing the shaking force also balances the shaking moment. Shaking torque is balanced by eliminating the angular momentum of each mechanism loop and by arranging the phase angles of the crank throws. Four-, six-, and eight-cylinder engines are balanced in the numerical examples given. Two methods of completely balancing single-cylinder engines are also given.

This paper deals with the nonlinear dynamics and the stability of cantilevered pipes conveying fluid, where the fluid has a harmonic component of flow velocity, assumed to be small, superposed on a constant mean value. The mean flow velocity is near the critical value for which the pipe becomes unstable by flutter through a Hopf bifurcation. The partial differential equation is transformed into a set of ordinary differential equations (ODEs) using the Galerkin method. The equations of motion contain nonlinear inertial terms, and hence cannot be put into standard form for numerical integration. Various approaches are adopted to tackle the problem: (a) a perturbation method via which the nonlinear inertial terms are removed by finding an equivalent term using the linear equation; the system is then put into first-order form and integrated using a Runge-Kutta scheme; (b) a finite difference method based on Houbolt’s scheme, which leads to a set of nonlinear algebraic equations that is solved with a Newton-Raphson approach; (c) the stability boundaries are obtained using an incremental harmonic balance method as proposed by S.L. Lau. Using the three methods, the dynamics of the pipe conveying fluid is investigated in detail. For example, the effects of (i) the forcing frequency, (ii) the perturbation amplitude, and (iii) the flow velocity are considered. Particular attention is paid to the effects of the nonlinear terms. These results are compared with experiments undertaken in our laboratory, utilizing elastomer pipes conveying water. The pulsating component of the flow is generated by a plunger pump, and the motions are monitored by a noncontacting optical follower system. It is shown, both numerically and experimentally, that periodic and quasiperiodic oscillations can exist, depending on the parameters.

Several methods exist for the determination of profiles of cutting tools which work by wrapping. Most of these methods are based on the envelope theory and most often require cumbersome analytical formulations and the solution of equations not always easy to resolve. This work, based on the principle of minimal distance first proposed in a previous work of the second author, presents a new purely numerical method for the calculation of the active profile of the cutting tools which work by wrapping (direct problem) as well as for the estimation of the effectively generated surface on the workpiece when the tool is known at discrete points (inverse problem). The method can be used for any nonstandard profiles when an analytical description of the surfaces is not available. Several examples are shown for machining ball screws and parts of helical pumps.

Heat transfer and attendant temperature rises in a novel micropumping device, are studied numerically. The full two-dimensional Navier-Stokes and energy equations, the latter with viscous dissipation terms retained, are solved using a finite-volume methodology. The effects of Prandtl number and pump size are explored. In addition, an approximate one-dimensional thermal model is developed and the comparisons with the more precise numerical model yielded close agreement in the computed bulk temperature distributions along the pump. For large Eckert numbers, the results indicate that enhancements in the hydrodynamics of pumping could be accompanied by extremely high temperature gradients. Finally, the system transients were found to be restricted to rather large times from startup for some proposed micropumping applications, suggesting the possibility of designing pump operating cycles to circumvent the problem of heat build-up due to viscous dissipation.

In previous studies we have considered several types of positive displacement rotary pumps and deeply analyzed the generation of the flow rate and the design limits. This has been done in order to evaluate the main performance indexes: one of these, the flow rate irregularity, is related to the possibility that the pump becomes a source of vibration and noise. A second index is the specific flow rate, related to the delivery capacity of the pump. In this paper, following our previous researches, we analyze internal involute gear pumps and internal lobe pumps, that have similar way to operate but different performances. The design parameters and the way to optimize the performances are summarized for both cases. Finally a comparison between the two types of pumps is proposed, along with some optimum design cases.

Belt drives have long been utilized in engine applications to power accessories such as alternators, pumps, compressors and fans. Drives employing a single, flat, ‘serpentine belt’ tensioned by an ‘automatic tensioner’ are now common in automotive engine applications. The automatic tensioner helps maintain constant belt tension and to dissipate unwanted belt drive vibration through dry friction. The objective of this study is to predict the periodic rotational response of the entire drive to harmonic excitation from the crankshaft. To this end, a multi-degree of freedom incremental harmonic balance (IHB) method is utilized to compute periodic solutions to the nonlinear equations of motion over a wide range of engine speeds. Computed results illustrate primary and secondary resonances of accessories and tensioner stick-slip motions.

The exponential growth of the Internet and the increasing communication and computational power have created many opportunities for advancing engineering, manufacturing and business activities. Active Catalog brings a conceptually new idea to design and electronic commerce by providing new forms of catalog information about engineering parts and physical objects. Active Catalog is designed for finding and using information in building design applications in the context of heterogeneous, Internet-based distributed computing environments. The information provided by Active Catalog is active, dynamic, composable, multi-dimensional, share-able, semantically accessible, interoperable and executable in distributed environments. Active Catalog allows engineers and designers to search for information about catalog parts syntactically and semantically, use that information to construct simulation programs rapidly, and test out their designs on the Internet before committing to actual fabrication of physical systems. It supports a new “Try Before You Buy” paradigm in the Internet-based design and electronic commerce. This paper presents a number of research issues and our approach in building an Internet-based catalog information resource. The paper describes an initial prototype toward realizing the “Try Before You Buy” paradigm, in the context of the electromechanical design of pump and motor systems. The prototype contains a pump ontology and a search engine for finding semantically equivalent parts. The paper also describes a distributed simulation, which runs on various machines, and exchanges dynamic information using commercial data exchange mechanisms.