Influence of Flow Conditions on Deposits From Heated Hydrocarbon Fuels

1993 ◽  
Vol 115 (3) ◽  
pp. 433-438 ◽  
Author(s):  
J. S. Chin ◽  
A. H. Lefebvre
Keyword(s):  
Wall Temperature ◽  
Liquid Hydrocarbon ◽  
Hydrocarbon Fuels ◽  
Test Duration ◽  
Flow Conditions ◽  
Fuel Temperature ◽  
Deposition Rates ◽  
Pass System ◽  
Heated Tube ◽  
Before And After

The thermal stability characteristics of two liquid hydrocarbon fuels are examined using a single-pass system whereby the fuel under test flows only once through a heated tube which is maintained at constant temperature throughout a test duration of six hours. Deposition rates on the tube walls are measured by weighing the tube before and after each test. The experimental data are used to derive empirical equations for predicting the effects on deposition rates of variation in fuel temperature, wall temperature, and Reynolds number. It is found that deposition rates are enhanced by increases in fuel temperature, wall temperature and flow velocity, and by reductions in tube diameter. Pressure has no effect on deposition rates provided it is high enough to prevent fuel boiling.

scholarly journals Influence of Flow Conditions on Deposits From Heated Hydrocarbon Fuels

1992 ◽  
Author(s):  
J. S. Chin ◽  
A. H. Lefebvre
Keyword(s):  
Wall Temperature ◽  
Liquid Hydrocarbon ◽  
Hydrocarbon Fuels ◽  
Test Duration ◽  
Flow Conditions ◽  
Fuel Temperature ◽  
Deposition Rates ◽  
Pass System ◽  
Heated Tube ◽  
Before And After

The thermal stability characteristics of two liquid hydrocarbon fuels are examined using a single-pass system whereby the fuel under test flows only once through a heated tube which is maintained at constant temperature throughout a test duration of six hours. Deposition rates on the tube walls are measured by weighing the tube before and after each test. The experimental data are used to derive empirical equations for predicting the effects on deposition rates of variation in fuel temperature, wall temperature, and Reynolds number. It is found that deposition rates are enhanced by increases in fuel temperature, wall temperature and flow velocity, and by reductions in tube diameter. Pressure has no effect on deposition rates provided it is high enough to prevent fuel boiling.

scholarly journals Temperature Effects on Fuel Thermal Stability

1991 ◽  
Author(s):  
J. S. Chin ◽  
A. H. Lefebvre ◽  
F. T.-Y. Sun
Keyword(s):  
Thermal Stability ◽  
Wall Temperature ◽  
Tube Wall ◽  
Fuel Temperature ◽  
Deposition Rates ◽  
Heated Tube ◽  
Increase With Increase ◽  
Before And After ◽  
Tube Wall Temperature ◽  
The Impact

The thermal stability characteristics of four kerosine-type fuels are examined using a heated-tube apparatus which allows independent control of fuel pressure, fuel temperature, tube-wall temperature, and fuel flow rate. It is a closed loop system, and fuet flows through the heated tube for periods ranging from 6 to 22 hrs. The deposition rates of carbon on the tube walls are measured by weighing the tube before and after each test. The results obtained show that tube-wall and fuel temperatures both have a marked influence on deposition rates, the impact of fuel temperature being stronger than that of wall temperature. It is also found that deposition rates increase continuously with increases in tube-wall temperature. This finding contradicts the results of previous studies which had led to the conclusion that deposition rates increase with increase in wall temperature up to a certain value beyond which any further increase in wall temperature causes the deposition rate to decline.

Temperature Effects on Fuel Thermal Stability

1992 ◽  
Vol 114 (2) ◽  
pp. 353-358 ◽  
Author(s):  
J. S. Chin ◽  
A. H. Lefebvre ◽  
F. T.-Y. Sun
Keyword(s):  
Thermal Stability ◽  
Wall Temperature ◽  
Tube Wall ◽  
Fuel Temperature ◽  
Deposition Rates ◽  
Heated Tube ◽  
Increase With Increase ◽  
Before And After ◽  
Tube Wall Temperature ◽  
The Impact

The thermal stability characteristics of four kerosine-type fuels are examined using a heated-tube apparatus that allows independent control of fuel pressure, fuel temperature, tube-wall temperature, and fuel flow rate. It is a closed loop system, and fuel flows through the heated tube for periods ranging from 6 to 22 h. The deposition rates of carbon on the tube walls are measured by weighing the tube before and after each test. The results obtained show that tube-wall and fuel temperatures both have a marked influence on deposition rates, the impact of fuel temperature being stronger than that of wall temperature. It is also found that deposition rates increase continuously with increases in tube-wall temperature. This finding contradicts the results of previous studies, which had led to the conclusion that deposition rates increase with increase in wall temperature up to a certain value, beyond which any further increase in wall temperature causes the deposition rate to decline.

An Experimental Investigation of Flow Boiling Characteristics in a Single Transparent Heated Microtube

2009 ◽  
Author(s):  
Osamu Kawanami ◽  
Shih-Che Huang ◽  
Kazunari Kawakami ◽  
Itsuro Honda ◽  
Yousuke Kawashima ◽  
...  
Keyword(s):  
Heat Flux ◽  
Wall Temperature ◽  
Mass Velocity ◽  
Tube Wall ◽  
Flow Boiling ◽  
High Mass ◽  
Test Fluid ◽  
High Heat Flux ◽  
Gold Plating ◽  
Heated Tube

In the present study, flow boiling in a transparent heated microtube having a diameter of 1 mm was investigated in detail. The transparent heated tube was manufactured by the electroless gold plating method. The enclosed gas-liquid interface could be clearly recognized through the tube wall, and the inner wall temperature measurement and direct heating of the film were simultaneously conducted by using the tube. Deaerated and deionized water that was subcooled temperature of 15 K was used as a test fluid, and constant and stable mass velocities of 50, 100, and 200 kg/m2s were provided by using a twin plunger pump. Among our experimental results, a vapor bubble grew up in a direction opposite the flow at a low heat flux and low mass velocities; however, this flow pattern was not observed at a high mass velocity of 200 kg/m2s. Under the conditions of G = 50 kg/m2s and high heat flux, the liquid film surrounding an elongated bubble near the heated tube wall occasionally thickened partially. The inner wall temperature exhibited large random oscillations in this regime; however, the visual observation revealed that dry-patches did not occur. The mass velocity had a negligible effect on the boiling heat transfer except in the counter-growth bubble flow regime.

Experimental study of the ignition of liquid hydrocarbon fuels and stabilization of their combustion by an arc discharge

2012 ◽  
Vol 38 (13) ◽  
pp. 1073-1077 ◽  
Author(s):  
V. A. Bityurin ◽  
V. Yu. Velikodnyi ◽  
B. N. Tolkunov ◽  
A. A. Bykov ◽  
A. V. Dyrenkov ◽  
...  
Keyword(s):  
Experimental Study ◽  
Arc Discharge ◽  
Liquid Hydrocarbon ◽  
Hydrocarbon Fuels

Characteristics and origin of myogenic response in isolated gracilis muscle arterioles

1994 ◽  
Vol 266 (3) ◽  
pp. H1177-H1183 ◽  
Author(s):  
D. Sun ◽  
G. Kaley ◽  
A. Koller
Keyword(s):  
Pressure Range ◽  
Perfusion Pressure ◽  
Gracilis Muscle ◽  
Tetraacetic Acid ◽  
Flow Conditions ◽  
Third Order ◽  
Before And After ◽  
Physiological Pressure ◽  
Arteriolar Diameter ◽  
Intravascular Pressure

Responses to changes in intravascular pressure of isolated rat gracilis muscle arterioles were investigated under no-flow conditions. First-, second-, and third- order arterioles were isolated and cannulated. Vascular diameters were measured with an image-shearing device and then recorded. In response to the step increases in perfusion pressure (from 20 to 160 mmHg, by 10- or 20-mmHg steps) arterioles constricted and developed active tone. For example, at 100, 80, and 50 mmHg pressure the steady-state active diameters of 1st-, 2nd-, and 3rd-order arterioles were 76.9 +/- 1.6, 32.3 +/- 1.1 and 22.3 +/- 3.2 microns, respectively. At the same perfusion pressure, by use of a Ca(2+)-free solution (ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid; 1 mM) containing sodium nitroprusside (SNP; 10(-4) M), the passive diameters (PD) of these vessels were 161.8 +/- 3.2, 76.0 +/- 1.7, and 47.6 +/- 2.2 microns. The negative slopes of the pressure-diameter curves indicate that in the physiological pressure range an inverse relationship exists between the arteriolar diameter and intravascular pressure. The maximum constriction expressed as a percent of PD was similar in the various sized arterioles (approximately 60%) but was reached at lower pressures in the smaller vessels. The vasoactive function of endothelium and vascular smooth muscle was assessed by the responses of arterioles to acetylcholine (ACh; 10(-6) M) and SNP (5 x 10(-8) M) before and after removal of the endothelium with air. After removal of the endothelium, dilation to ACh was abolished while dilation to SNP was retained.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Experimental and field verifications of radial gates as flow measurement structures

2021 ◽  
Author(s):  
Hossein Khalili Shayan ◽  
Javad Farhoudi ◽  
Alireza Vatankhah
Keyword(s):  
Field Measurements ◽  
The United States ◽  
Data Series ◽  
Flow Conditions ◽  
Flow Limit ◽  
Before And After ◽  
Energy And Momentum ◽  
Extensive Experimental Data ◽  
Radial Gate ◽  
Discharge Curves

Abstract Radial gates are common structures in irrigation projects. This paper presents some theoretical-based equations for explicit estimation of the discharge from the radial gate under free and submerged flow conditions using Energy and Momentum (E-M) principles. The proposed equations were calibrated using extensive experimental data collected from the literature and this study for three types of radial gates under free and submerged flow conditions. The submergence threshold of radial gates is concluded, based on the concepts of hydraulic jump and the intersection of free and submerged head-discharge curves. The results indicated that the error in estimating the discharge increases under transition ( − 2.5 ≤ Sr% ≤ + 2.5), gate lip (1 < y0/w ≤ 2), and high submerged (yt/y0 ≥ 0.95) flow conditions. However, in these flow limit conditions, the discharge error can be considerably decreased by adjusting the tailwater depth to flow depth just after the gate and using the energy equation for the sections before and after the gate. The efficiency of the proposed methods was evaluated based on the data series from field measurements of radial gates in 29 check structures at irrigation canals in the United States and Iran. The results showed that the discharge could be estimated using the proposed equations in field conditions with acceptable accuracy.

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