Rotor Concept Research Articles

Partitron 25, a Multi‐Purpose Industrial Centrifugal Partition Chromatograph: Rotor Design and Preliminary Results on Efficiency and Stationary Phase Retention

A new preparative chromatograph with a capacity of 25 liters has been designed to meet the most rigorous industrial criteria. All parts contacting liquid phases are made of titanium. The rotor, cast in one piece, can be operated up to 150 bars (2,000 psi). Preliminary results on retention of the liquid stationary phases from non‐aqueous and aqueous–aqueous biphasic solvent systems are presented and commented. A special emphasis is made on the theoretical plate number generated by each individual partition cell. The results highlight the benefit of a new concept of rotor featuring a better mass transfer than that observed in the stacked disk rotors. Finally, the use of neoteric solvents (ionic liquids, supercritical carbon dioxide) is mentioned.

On the stability of multiple helical vortices

The classical problem of linear stability of a regular helical vortex array was originally obtained as an additional intermediate result. The new formula allows accurate calculations to be made within the whole range of helical pitch variations and has a simpler form than the known asymptotic expressions.Solution of these two classical problems of vortex dynamics has significance both for theoretic and applied mechanics, as well as for many other areas of natural science, where the rotor (vortex) concept is the basic one.

Radial and axial flux superconducting motors in a levitating rotor configuration

The capability of superconducting blocks to be partially magnetized allows both bearing and powering functions in a conventional stator and superconducting rotor configuration. This levitating rotor concept is investigated by means of the basic parameters: torque, levitation and centering forces in two motors with radial and axial excitation respectively. We report on the design and behavior of a high speed motor with a cylindrical HTSC rotor excited by a conventional four poles four phases armature generating a radial field. We also report on a second motor with a disk shaped HTSC rotor excited by a conventional, four poles three phases, double armature which generates an axial field in the gap. Torque, power and centering and levitating forces measurements are also provided.

Active control to augment rotor lead-lag damping

AbstractHingeless and bearingless rotor designs are today well accepted for modern helicopters. Continued development, however, revealed some deficiencies in the area of aeromechanical stability and vibration. In general there is a good basic understanding of how to avoid these instabilities. But since it becomes more and more desirable to focus rotor design on aerodynamic features and flight performance, these aeromechanical instabilities gain new importance due to the difficulties to provide the required damping.Since all rotor concepts suffer from the lack of sufficient natural lead-lag or inplane damping most designs in use show artificial lead-lag dampers to overcome aeromechanical instabilities. Additionally, active control offers the possibility for an artificial stabilisation of aeromechanical instabilities. Meanwhile, many research activities focus on active control to augment rotor lead-lag damping and many authors demonstrate the potential inherent in this approach.

Rotoradsorber zur Abluftreinigung und Lösungsmittel‐Rückgewinnung

AbstractRotary Adsorbers for Waste Air Purification and Solvent Recovery. Thanks to their compact construction and low pressure drops, adsorbers with rotating adsorbent beds are highly suitable both for retrofitting of waste air purification units and generally for the removal of absorbable components from gas streams. When used in conjunction with straightforward hot gas desorption they permit almost complete purification of gas flows with concomitant concentration of the separated components in the desorbate by a factor of 10 to 20. They can also be used in conjunction with recovery of the separated components by partial condensation of the desorbate. Owing to the fixed coupling of adsorption and desorption times, which is determined by the geometry of the unit, the behaviour of the system is distinctly different from that of conventional multiple bed systems in cyclic operation. A detailed model description and computer simulation of operating behaviour are particularly useful for their analysis. It is shown that the behaviour of commercially available rotor concepts can be much better understood in this way and new concepts for exhaust air purification with integrated solvent recovery can be developed which are characterised by significantly reduced energy requirements for desorption and condensation.

Photo-optical liquid crystal cells driven by molecular rotors

Photochemical regulation of in-plane alignment of a nematic liquid crystal is presented. A quartz plate surface was modified with 4-hexyl-4′-hexyloxyazobenzene substituted with triethoxysilyl group through a spacer at the 2′ position to introduce the side-on type azobenzene unit of the surface. A liquid crystal hybrid cell fabricated with the azo-modified plate was irradiated with linearly polarized visible light for the n-π* transition. This resulted in the in-plane reorientation of the liquid crystal molecules to afford homogeneous alignment. Discussion is made on the mechanism of the in-plane alignment regulation, and the concept of a molecular rotor is proposed.

The delta-wing bladed rotor concept

A description is given of a new type of horizontal axis wind-turbine rotor incorporating sharp-edged, flap-equipped, fixed pitch, delta-wing-like blades. It is shown that rotors of this type can attain a maximum torque coefficient at zero tip-speed ratio whilst achieving a maximum power coefficient of 0.43 at a tip-speed ratio of approximately 1.7: the runaway tip-speed ratio is about 3.2. Applications of the delta-wing-bladed rotor concept to both water pumping and electric power generation are discussed. It is shown that the new form of rotor is particularly suited for water pumping duties. It is also shown that it has potential for electrical power generation applications in situations where the rotor noise of conventional wind-electric machines is a major problem. A very low tip-speed ratio version of the delta-wing-bladed turbine is also described briefly. The latter form of rotor was conceived especially for the task of driving reciprocating deep-well pumps without the intervention of reduction gearing between the turbine shaft and the pump.

Mapping degenerate perturbations in atoms onto an asymmetric rotor.

Several problems in atomic physics, such as diamagnetism in high Rydberg states, or the electron-electron interaction in high doubly excited states, and analogous problems at high excitation in nuclear physics or in other branches of physics, display certain characteristic and common features. Among these are the existence of classes of sharply localized states formed through large superpositions of basis states that are degenerate in the absence of the interaction. The asymmetric rotor at high angular momentum J displays these same features: In particular, most of its eigenstates divide into two groups with different localizations (along the directions of minimum and maximum moments of inertia). A few states lie in a ``separatrix'' region in between, corresponding to localization along the axis with an intermediate moment of inertia. A 1:1 mapping is made from the atomic and nuclear problems into the asymmetric rotor, wherein the principal quantum number n and orbital angular momentum l of the former are put in correspondence, respectively, with J and M, the azimuthal projection of the rotor's angular momentum. For each given problem, the ``asymmetry parameter'' of the corresponding rotor is identified, and eigenvalues and eigenfunctions are presented. The concept of a conjugate rotor is also introduced. The key, common feature that underlies localization is the vanishing as l\ensuremath{\rightarrow}n of the off-diagonal coupling between the states in a degenerate manifold {nl} just as in the asymmetric rotor where the matrix elements of the step-up and step-down operators in the \ensuremath{\Vert}JM〉 basis vanish when M\ensuremath{\rightarrow}\ifmmode\pm\else\textpm\fi{}J.

A vectored-thrust rotor for helicopter anti-torque applications

SummaryA rotor concept is described that enables the generation of a controlled thrust vector in any direction within the rotor’s sphere of action. It is suggested that a rotor of this kind might replace the entire tail unit of the ‘conventional’ single-rotor helicopter to provide a lighter, more compact layout of improved performance. An active control system might be required for the ‘flying-tail’ layout envisaged.Some of the structural and mechanical design problems that are posed by a vectored-thrust (VT) rotor are briefly discussed and are seemingly tractable by exploiting the potential of advanced composite materials.No assessment is made of the aerodynamic performance of a VT rotor, nor of the helicopter configurations or operational scenarios where a VT rotor might prove advantageous. Some limited assessments of this kind seem merited.

Quasi-Isotropic, Thick Composite Laminates Fabricated by the Matched Metal Die Compression Molding Process

One of the designs currently being explored under the DOE/LLL composite flywheel rotor development effort is the tapered thickness laminated disk “Stodola” rotor concept. The goal of this effort is to develop a prototype high-energy-density, economical composite laminate rotor for utilization in hybrid flywheel/electric/ICE vehicles and in stationary applications. In terms of energy density, the objective is to obtain 88 Wh/kg at failure with an operational range of 44–55 Wh/kg and an energy storage capacity of approximately 1 kWh. To that end, a high-strength graphite/epoxy (Celion 6000/5213) (0/±45/90) composite laminate tapered disk was fabricated and spin tested. Table 1 presents the test results. It appears from Table 1 that the governing failure criterion is the off-axis failure strength, which is typically lower than the strength along the fiber direction in most quasi-isotropic laminates. This strength anisotropy results in the under-utilization of the laminate strength and in lower energy densities. This suggests that there are two avenues open to improve the performance of laminated disk rotors: (1) increase the basic strength of the composite, and (2) reduce the strength anisotropy of the laminate.

Self-regulating composite bearingless wind turbine

The Composite Bearingless Rotor (CBR) concept has been shown to have characteristics ideally suited for wind turbine applications. Originally developed for helicopters to reduce weight, costs and complexity, the CBR eliminates blade bearings and hinges through the utilization of the unique structural characteristics of uniaxial composite materials. This rotor concept was further developed under an ERDA contract to provide a fully self-regulating and self-aligning wind turbine. Such a system was achieved without the need for auxiliary controls or sensors. These features allow self-starting for wind initiating from any direction and automatic pitch and yaw variations to optimize performance under all normal wind conditions. The work described in this report consists of the design and fabrication of a 4.5 ft dynamically scaled wind turbine model and the successful testing of this model in the United Technologies Research Center low speed wind tunnel.

Results of Preliminary Studies of a Bearingless Helicopter Rotor Concept

Results of Preliminary Studies of a Bearingless Helicopter Rotor Concept