Development of a Household Vacuum Cleaner With a New Cyclone Dust Collector

Author(s):  
Shoji Hayashi ◽  
Masatoshi Watanabe ◽  
Yukiji Iwase ◽  
Kyoichi Kanno ◽  
Keiichi Fujimori

A household vacuum cleaner named “Tatsumaki cyclone” with a new cyclone dust collector was developed. It has a unique horizontal layout called the inverted cyclone layout that features a dust bunker adjacent to a cyclone cylinder with an up-draught airflow. It also has a new airflow arrangement called triple-suction airflow that separates airflow after removing dust at the cyclone cylinder. The main suction airflow is exhausted from the main port (which is downstream of the cyclone cylinder) through an inner cylinder. The sub-suction airflow is exhausted from the dust bunker after it heavily compresses the dust (sub port). The center suction airflow is exhausted from the center port. In this study, we used the Cartesian grid system to simulate the flow field inside the dust collector. This system uses only rectangular parallelepiped meshes; profiles of the dust collector were represented by stepped surfaces of cubic meshes. Each mesh was generated based on whether it was inside or outside the solid body of the dust collector. High-performance computers have recently been used to help generate super-fine meshes that fit closely the smooth shape of a dust collector. The Cartesian grid system has the advantage of being able to quickly generate square-meshes of complex shape that can be converted directly from the CAD data. We simulated the velocity distribution of single-suction, twin-suction and triple-suction models. The single-suction model had only a main port to exhaust airflow, the twin-suction model had a main port, and a sub port, and the triple-suction model had a main port, a sub port, and a center port. In this study, a Cartesian grid system with a finite difference method was used to correct the unsteady three-dimensional flows. After the simulation, we experimented with pressure losses and measured change in air quantity by the dust load of each model. These steps enabled us to develop a new cyclone dust collector called Tatsumaki cyclone as part of a compact household vacuum cleaner with lower pressure loss and a larger capacity dust bunker.

Author(s):  
T. Stylianopoulos ◽  
A. Yeckel ◽  
J. J. Derby ◽  
X. J. Luo ◽  
M. S. Shephard ◽  
...  

The study of creeping flow in fibrous media is of considerable interest in many biological and biomedical applications. There is little work, however, on permeability calculations in three-dimensional random networks. Computational power is now sufficient to calculate permeabilities directly by constructing artificial fiber networks and simulating flow through them. Even with today’s high-performance computers, however, such an approach would be infeasible for large simulations. It is therefore necessary to develop a correlation based on fiber volume fraction, radius and orientation, preferably by incorporating previous studies on isotropic or structured networks. In this work, the direct calculations were performed, using the finite element method, on networks with varying degrees of orientation, and combinations of results for flow parallel and perpendicular to a single fiber or an array thereof, using a volume averaging theory, were compared to the detailed analysis.


Author(s):  
N. Isoshima ◽  
M. Watanabe ◽  
H. Saito

We developed a voxel code using a finite difference method for unsteady three-dimensional thermal flows in a Cartesian grid system. This code enables us to predict flow fields around complicated geometries in a short pre-processing time. The code was used to predict flow fields around a flat plate that was heated to a constant temperature, and the results were within 20% of those obtained using analytical solutions. The code was also used to predict the flow field of a liquid crystal display (LCD) projector that has highly complicated internal structures such as a lamp, LCD panels, electric parts, etc.


2014 ◽  
Vol 2014 (1) ◽  
pp. 000213-000216
Author(s):  
Taiga Fukumori ◽  
Tomoyuki Akahoshi ◽  
Daisuke Mizutani ◽  
Motoaki Tani

Weave induced skew in printed wiring boards (PWB) in high-performance computers has become a significant problem as data rates have increased. We present a new method to reduce weave induced skew. Using three-dimensional electromagnetic simulation, we have discovered that skew can be reduced by adjusting the line width to a specific value, and that the specific values are approximately the same for both stripline and microstripline. We have ascertained the effect in actual PWB manufacturing and measurement. As a result, we have verified by measurement that skew can be reduced to less than one-third. Investigation of a wider range of line width / weave pitches by simulation suggests that skew can be reduced to less than one-tenth of a usual structure.


Author(s):  
Lee D. Peachey ◽  
Lou Fodor ◽  
John C. Haselgrove ◽  
Stanley M. Dunn ◽  
Junqing Huang

Stereo pairs of electron microscope images provide valuable visual impressions of the three-dimensional nature of specimens, including biological objects. Beyond this one seeks quantitatively accurate models and measurements of the three dimensional positions and sizes of structures in the specimen. In our laboratory, we have sought to combine high resolution video cameras with high performance computer graphics systems to improve both the ease of building 3D reconstructions and the accuracy of 3D measurements, by using multiple tilt images of the same specimen tilted over a wider range of angles than can be viewed stereoscopically. Ultimately we also wish to automate the reconstruction and measurement process, and have initiated work in that direction.Figure 1 is a stereo pair of 400 kV images from a 1 micrometer thick transverse section of frog skeletal muscle stained with the Golgi stain. This stain selectively increases the density of the transverse tubular network in these muscle cells, and it is this network that we reconstruct in this example.


2020 ◽  
Author(s):  
Peiyao Wang ◽  
Bangchuan Zhao ◽  
Jin Bai ◽  
Kunzhen Li ◽  
Hongyang Ma ◽  
...  

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