Entity

Time filter

Source Type

Bellingham, WA, United States

Walton O.,Grainflow Dynamics, Inc. | Vollmer H.,Grainflow Dynamics, Inc. | Vollmer B.,Grainflow Dynamics, Inc. | Figueroa L.,Grainflow Dynamics, Inc. | And 2 more authors.
7th Symposium on Space Resource Utilization | Year: 2014

Flexible screw conveyors utilizing compliant components can provide an enclosed dust-free, light-weight means for conveying regolith at any orientation from horizontal to vertical and around gentle bends. Simulations of straight conveying lines agreed with lab measurements of torques and mass flow rates, and also indicated that conveying efficiency increases as the gravitational level decreases. Designs utilizing a high-torque-capable flexible central shaft and a compliant helical outer band along the screw periphery provided robust transport, avoiding binding, grinding and/or comminution of material - issues often associated with rigid screw conveyors. Curved conveying without the use of drilling mud or pneumatic transport to assist in removing drill-cuttings could be an enabling technology for 'horizontal' lunar volatile-extractions wells (e.g., for extraction of subsurface water ice). Source


Tokunaga Y.,Eagle Engineering | Sugimura J.,Kyushu University | Yamamoto Y.,Kyushu University
Toraibarojisuto/Journal of Japanese Society of Tribologists | Year: 2015

A series of experiments were carried out to verify the sealing and lubricating performance of the surface structure for mechanical seals with the functions of the low-friction, the low-leakage, and also the pumping effect. The thrust bearing structures were formed in the higher pressure side as a lubricating mechanism, and the reversed thrust bearing structures were formed in the lower pressure side as a sealing mechanism in the mechanical seals' surfaces. The fluid film thickness and the friction coefficient were measured and compared with the numerical calculation results of our previous report. Cavitation regions formed in the sliding surface were observed with the direct observation system of mechanical seals. Furthermore, the magnitude of the cavitation pressure was also discussed. The experimental results indicated that the theoretical results discussed in our previous report were proved to be valid. Thus we conclude that the novel sealing and lubricating mechanisms for mechanical seals with the functions of the low-friction, the low-leakage and the pumping effect can be technically feasible. Source


Meroney R.N.,Eagle Engineering
Journal of Wind Engineering and Industrial Aerodynamics | Year: 2012

Numerical calculations were performed to reproduce the transport and dispersion of the instantaneous release of finite volumes of dense gases over homogeneous flat, sloped, and complex terrain surfaces for calm and windy situations. The 1981 Porton Trial Test 8 field study of the release of 40m 3 of a Freon-air mixture was used as a validation case to evaluate the behavior of volume integrated, cross-section integrated , depth integrated and full 3-d CFD models. In addition wind-tunnel measurements by Meroney & Lohmeyer (1983, 1984) about an instantaneous cloud of dense gas released in a wind were reproduced by similar calculations. All results were inter-compared, and time-dependent cloud dimensions, arrival times, and concentrations were considered. Very similar behavior was found for all models which tend to validate all methods as useful predictors. © 2012 Elsevier Ltd. Source


Tokunaga Y.,Eagle Engineering | Uemura N.,Eagle Industry Co. | Yamamoto Y.,Kyushu University
Toraibarojisuto/Journal of Japanese Society of Tribologists | Year: 2013

One of the most important but complicated issues for mechanical seals is how to realize two contradictory functions: the sealing and the lubricating performance between the seal surfaces. Various studies have been carried out to solve the problem. However, few fundamental solutions have been presented so far. In our previous report, the surface structure for achieving the low-friction and low-leakage mechanical seals was proposed. In this report, the fundamental characteristics of sealing and lubricating function for the surface structures that we proposed in previous report were investigated by numerical calculations. Jakobsson-Floberg's boundary condition was applied in order to consider the mass conservation at the cavitation boundary. Moreover, the effect of cavitation pressure on the sealing and lubricating performance were also investigated. The results indicated that the surface structure could simplify and clarify the surface design procedure for mechanical seals, and could predict and control the leakage rate and the film thickness based on hydrodynamic lubrication theory. Source


Meroney R.N.,Eagle Engineering
Atmospheric Environment | Year: 2012

Numerical calculations are performed to reproduce the transport and dispersion of the continuous release of dense gases over flat homogeneous surfaces with and without the mitigating influence of a downwind water curtain. Frequently such plumes are released as a result of a chemical manufacturing, storage or gas transportation accident resulting in a ground-level hazard due to gas flammability or toxicity. A field situation in which cold carbon dioxide was released upwind of water curtains (Moodie et al., 1981) was simulated using the open-source software FDS (Fire Dynamic Simulator) a full 3-d CFD model. Only water-spray enhancement of dispersion was considered; hence, no chemical removal or reactions were present or simulated. Wind-tunnel measurements for a 1:28.9 scale replication of the Moodie experiments are also compared with the 3-d CFD results. Concentration distributions, percent dilution and forced diffusion parameters were compared in scatter diagrams. Concentration field contours with and without active spray curtains are also presented. © 2012 Elsevier Ltd. Source

Discover hidden collaborations