Study on Behavior of Methane/Oxygen Gas Detonation Near Propagation Limit in Small Diameter Tube: Effect of Tube Diameter

2016 ◽  
Vol 188 (11-12) ◽  
pp. 2012-2025 ◽  
Author(s):  
Keisuke Yoshida ◽  
Koichi Hayashi ◽  
Youhi Morii ◽  
Kiyoto Murakami ◽  
Nobuyuki Tsuboi ◽  
...  
Keyword(s):  
Small Diameter ◽  
Tube Diameter ◽  
Gas Detonation ◽  
Propagation Limit ◽  
Oxygen Gas

Air-Side Heat Transfer and Friction Correlations for Plain Fin-and-Tube Heat Exchangers With Staggered Tube Arrangements

1999 ◽  
Vol 121 (3) ◽  
pp. 662-667 ◽  
Author(s):  
N. H. Kim ◽  
B. Youn ◽  
R. L. Webb
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Small Diameter ◽  
Tube Diameter ◽  
Heat Transfer Correlation ◽  
Multiple Regression Technique ◽  
Geometric Variables ◽  
Tube Pitch ◽  
Fin Spacing

This paper deals with heat exchangers having plain fins on a staggered array of circular tubes. Correlations are developed to predict the air-side heat transfer coefficient and friction factor as a function of the Reynolds number and geometric variables of the heat exchanger such as tube diameter, tube pitch, fin spacing, etc. A multiple regression technique was used to correlate 47 sets of heat exchanger data to develop the heat transfer and friction correlation. The correlations are applicable to heat exchangers having small diameter tubes (or large tube pitch to tube diameter ratio), whose performance previous correlations failed to predict adequately. The heat transfer correlation applicable to three or more row configuration predicts 94 percent of the data within ±20 percent, and the heat transfer correlation applicable to one- or two-row configuration predicts 94 percent of the data within ±20 percent. The friction correlation predicts 90 percent of the data within ±20 percent.

Boiling Heat Transfer of R-134a Flowing in Horizontal Small-Diameter Tubes

2007 ◽  
Author(s):  
Shizuo Saitoh ◽  
Hirofumi Daiguji ◽  
Eiji Hihara
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Boiling Heat Transfer ◽  
Small Diameter ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Tube Diameter ◽  
Local Heat Transfer Coefficient ◽  
R 134A

The boiling heat transfer of refrigerant R-134a flow in horizontal small-diameter tubes with inner diameter of 0.51, 1.12, 2.0 and 3.1 mm was experimentally investigated. Local heat transfer coefficient and pressure drop were measured at a heat flux ranging from 5 to 39 kW/m2, mass flux from 100 to 450 kg/m2s, inlet vapor quality from 0 to 0.2, and evaporating pressure of 0.49 MPa, 3.0 and 3.7 MPa. Results showed that the local heat transfer coefficient tends to decrease at lower vapor quality with the decrease in tube diameter. The effect of heat flux on local heat transfer coefficient becomes significant with the decrease in tube diameter, while the effect of mass flux is weak especially for small diameter tube. With decreasing tube diameter, the flow inside it approached homogeneous flow, and the contribution of forced convective evaporation to the boiling heat transfer decreases. With the increase in pressure near the critical pressure (3.0 to 3.7 MPa), the heat transfer coefficient increased, and the effect of mass flux on the heat transfer coefficient became weak. These results implied that the nucleate boiling was dominant under high pressure conditions. A modified Chen-type correlation taking into account the effect of tube diameter was proposed for the prediction of boiling heat transfer of R-134a in horizontal tube. The effect of tube diameter on flow boiling heat transfer coefficient was characterized by the Weber number in gas phase. Comparison with experimental results showed that this correlation could be applied to a wide range of tube diameters (0.5 to 11 mm) and pressure conditions (reduced pressure from 0.1 to 0.9).

scholarly journals Gas mixture explosion as a tool for generating impulsive disturbances

2021 ◽  
Vol 43 (4) ◽  
pp. 166-175
Author(s):  
V.A. Polyakovskyi
Keyword(s):  
High Pressure ◽  
Seismic Waves ◽  
Seismic Exploration ◽  
Gas Mixture ◽  
Power Functions ◽  
Alternative Source ◽  
Gas Detonation ◽  
Oxygen Gas ◽  
Impulsive Disturbances ◽  
Properties Of Soil

The work is devoted to the development of a device for generating impulsive perturbations in soil massifs. It is proposed to use the explosion energy of a high-pressure acetylene-oxygen gas mixture as a source of impulse perturbations. Applying the standard method of measuring mechanical stresses and using piezoelectric sensors, it is obtained the stress fields occurring in the soils when an explosion of the gas mixture takes place. It is revealed that the dependences of the maximal stresses in the soil massif on the relative distance to the source, when the gas charge under high pressure acts, are the power functions. The exponents of power functions approximating these experimental dependences are obtained. The attenuation of the maximal radial stresses with the distance is considered for the two cases when the charges filled with gas mixture under low and high pressure act. The comparison of these cases indicates their similarity. In the paper it is also performed the analysis of modern methods of using explosive and non-explosive sources for seismic wave generation during investigations in the search geophysics. The existing structural sources of seismic waves used in the seismic exploration are analyzed in detail. The disadvantages and advantages of explosive and non-explosive impulsive sources of seismic waves are indicated. Among the advantages of the proposed wave sources it is worth noting their low price and mobility. There is no need to obtain special permits for their use. The obtained results allow one to expand the field of gas detonation application. In particular, it can be used as an alternative source of seismic waves. The proposed method is promising for training in search geophysics and in the study of properties of soil massifs.

A Replica Technique for the Inside Surfaces of Small Diameter Pipes and Tubes

1967 ◽  
Vol 25 ◽  
pp. 352-353
Author(s):  
T. G. Gregory
Keyword(s):  
Polyvinyl Chloride ◽  
Small Diameter ◽  
Replica Technique ◽  
Tube Size ◽  
Inside Diameter ◽  
Complete Inspection ◽  
Operating Limits

A nondestructive replica technique permitting complete inspection of bore surfaces having an inside diameter from 0.050 inch to 0.500 inch is described. Replicas are thermally formed on the outside surface of plastic tubing inflated in the bore of the sample being studied. This technique provides a new medium for inspection of bores that are too small or otherwise beyond the operating limits of conventional inspection methods.Bore replicas may be prepared by sliding a length of plastic tubing completely through the bore to be studied as shown in Figure 1. Polyvinyl chloride tubing suitable for this replica process is commercially available in sizes from 0.037- to 0.500-inch diameter. A tube size slightly smaller than the bore to be replicated should be used to facilitate insertion of the plastic replica blank into the bore.

Structural Organization and Distribution of Fiber Types in Extraocular Muscles of Cats

1972 ◽  
Vol 30 ◽  
pp. 34-35
Author(s):  
Asish C. Nag ◽  
Lee D. Peachey
Keyword(s):  
Fiber Type ◽  
Light And Electron Microscopy ◽  
Small Diameter ◽  
Extraocular Muscles ◽  
Fiber Types ◽  
Distinctive Features ◽  
Superior Rectus ◽  
Adult Cats ◽  
Different Diameters ◽  
Orbital Region

Cat extraocular muscles consist of two regions: orbital, and global. The orbital region contains predominantly small diameter fibers, while the global region contains a variety of fibers of different diameters. The differences in ultrastructural features among these muscle fibers indicate that the extraocular muscles of cats contain at least five structurally distinguishable types of fibers.Superior rectus muscles were studied by light and electron microscopy, mapping the distribution of each fiber type with its distinctive features. A mixture of 4% paraformaldehyde and 4% glutaraldehyde was perfused through the carotid arteries of anesthetized adult cats and applied locally to exposed superior rectus muscles during the perfusion.

Prospects for convergent beam electron diffraction with a 200kV cold field-emission transmission electron microscope

1991 ◽  
Vol 49 ◽  
pp. 466-467
Author(s):  
J W Steeds ◽  
R Vincent
Keyword(s):  
Field Emission ◽  
High Performance ◽  
Small Diameter ◽  
Convergent Beam Electron Diffraction ◽  
Zone Axis ◽  
Medium Voltage ◽  
Transmission Electron ◽  
Good Crystallinity ◽  
Special Modification ◽  
Convergent Beam

We review the analytical powers which will become more widely available as medium voltage (200-300kV) TEMs with facilities for CBED on a nanometre scale come onto the market. Of course, high performance cold field emission STEMs have now been in operation for about twenty years, but it is only in relatively few laboratories that special modification has permitted the performance of CBED experiments. Most notable amongst these pioneering projects is the work in Arizona by Cowley and Spence and, more recently, that in Cambridge by Rodenburg and McMullan.There are a large number of potential advantages of a high intensity, small diameter, focussed probe. We discuss first the advantages for probes larger than the projected unit cell of the crystal under investigation. In this situation we are able to perform CBED on local regions of good crystallinity. Zone axis patterns often contain information which is very sensitive to thickness changes as small as 5nm. In conventional CBED, with a lOnm source, it is very likely that the information will be degraded by thickness averaging within the illuminated area.

Applications of SIMS to electronic materials and devices

1992 ◽  
Vol 50 (2) ◽  
pp. 1682-1683
Author(s):  
S.F. Corcoran
Keyword(s):  
Depth Distribution ◽  
Secondary Ion Mass Spectrometry ◽  
Semiconductor Device ◽  
Electronic Materials ◽  
Profile Analysis ◽  
Semiconductor Industry ◽  
Small Diameter ◽  
Depth Resolution ◽  
Detection Sensitivity

Over the past decade secondary ion mass spectrometry (SIMS) has played an increasingly important role in the characterization of electronic materials and devices. The ability of SIMS to provide part per million detection sensitivity for most elements while maintaining excellent depth resolution has made this technique indispensable in the semiconductor industry. Today SIMS is used extensively in the characterization of dopant profiles, thin film analysis, and trace analysis in bulk materials. The SIMS technique also lends itself to 2-D and 3-D imaging via either the use of stigmatic ion optics or small diameter primary beams.By far the most common application of SIMS is the determination of the depth distribution of dopants (B, As, P) intentionally introduced into semiconductor materials via ion implantation or epitaxial growth. Such measurements are critical since the dopant concentration and depth distribution can seriously affect the performance of a semiconductor device. In a typical depth profile analysis, keV ion sputtering is used to remove successive layers the sample.

Sign in / Sign up

Export Citation Format

Share Document