Spreading behavior of firefighting foam solutions on typical liquid fuel surfaces

Author(s):  
Youjie Sheng ◽  
Yang Li ◽  
Kui Wu

Abstract A series of experiments was performed to investigate the spreading behavior of firefighting foam solutions on liquid fuel surfaces. The spreading coefficients of six kinds of aqueous film-forming foam solutions and one fluorine-free foam solution on the surface of four liquid fuels, namely, cyclohexane, diesel, n-heptane, and ethanol, were calculated on the basis of surface and interfacial tension. Spreading behavior was studied systematically using a high-speed camera, and then the relationship between spreading behavior and spreading coefficient was analyzed. Furthermore, the spreading area and spreading rate of different foam solution droplets on liquid fuel surfaces were studied in depth. The spreading amount of the foam solution droplets on the liquid fuel surfaces was measured. Four typical spreading phenomena, namely, spreading, suspension, dissolution, and sinking, of AFFF solutions on liquid fuel surfaces were identified. Moreover, a positive spreading coefficient did not necessarily lead to the formation of an aqueous film. The spreading area, spreading rate, and spreading amount were not proportional to the spreading coefficient. During the evaluation of the spreading property of firefighting foam, the spreading coefficient, spreading rate, and spreading amount must be focused on instead of only the spreading coefficient.

1996 ◽  
Vol 464 ◽  
Author(s):  
Anne D. Dussaud ◽  
Sandra M. Troian

ABSTRACTWe have investigated the spreading behavior of solvent droplets on a bulk water support using solvents with different vapor pressures and spreading coefficients. Instead of seeding the surface with tracer particles, as is usually done to track moving fronts, we employ laser shadowgraphy to visualize the entire surface of the spreading film including the leading edge. For non-volatile systems it has previously been shown that the leading edge advances in time as t3/4. We find that volatile systems with positive initial spreading coefficients exhibit two spreading fronts, both of which demonstrate power law growth but with exponents closer to 1/2. Surprisingly, differences in the liquid vapor pressure or the spreading coefficient seem only to effect the speed of advance but not the value of the exponent. We are presently investigating the behavior of the subsurface flow to determine the mechanism leading to the smaller spreading exponent.


2019 ◽  
Vol 47 (3) ◽  
pp. 196-210
Author(s):  
Meghashyam Panyam ◽  
Beshah Ayalew ◽  
Timothy Rhyne ◽  
Steve Cron ◽  
John Adcox

ABSTRACT This article presents a novel experimental technique for measuring in-plane deformations and vibration modes of a rotating nonpneumatic tire subjected to obstacle impacts. The tire was mounted on a modified quarter-car test rig, which was built around one of the drums of a 500-horse power chassis dynamometer at Clemson University's International Center for Automotive Research. A series of experiments were conducted using a high-speed camera to capture the event of the rotating tire coming into contact with a cleat attached to the surface of the drum. The resulting video was processed using a two-dimensional digital image correlation algorithm to obtain in-plane radial and tangential deformation fields of the tire. The dynamic mode decomposition algorithm was implemented on the deformation fields to extract the dominant frequencies that were excited in the tire upon contact with the cleat. It was observed that the deformations and the modal frequencies estimated using this method were within a reasonable range of expected values. In general, the results indicate that the method used in this study can be a useful tool in measuring in-plane deformations of rolling tires without the need for additional sensors and wiring.


Author(s):  
Bernhard Ćosić ◽  
Frank Reiss ◽  
Marc Blümer ◽  
Christian Frekers ◽  
Franklin Genin ◽  
...  

Abstract Industrial gas turbines like the MGT6000 are often operated as power supply or as mechanical drives. In these applications, liquid fuels like 'Diesel Fuel No.2' can be used either as main fuel or as backup fuel if natural gas is not reliably available. The MAN Gas Turbines (MGT) operate with the Advanced Can Combustion (ACC) system, which is capable of ultra-low NOx emissions for gaseous fuels. This system has been further developed to provide dry dual fuel capability. In the present paper, we describe the design and detailed experimental validation process of the liquid fuel injection, and its integration into the gas turbine package. A central lance with an integrated two-stage nozzle is employed as a liquid pilot stage, enabling ignition and start-up of the engine on liquid fuel only. The pilot stage is continuously operated, whereas the bulk of the liquid fuel is injected through the premixed combustor stage. The premixed stage comprises a set of four decentralized nozzles based on fluidic oscillator atomizers, wherein atomization of the liquid fuel is achieved through self-induced oscillations. We present results illustrating the spray, hydrodynamic, and emission performance of the injectors. Extensive testing of the burner at atmospheric and full load high-pressure conditions has been performed, before verification within full engine tests. We show the design of the fuel supply and distribution system. Finally, we discuss the integration of the dual fuel system into the standard gas turbine package of the MGT6000.


Author(s):  
Yefei Liu ◽  
Yang Liu ◽  
Xingtuan Yang ◽  
Liqiang Pan

Series of experiments are conducted in a single microchannel, where subcooled water flows upward inside a transparent and vertical microchannel. The cross section of the channel is rectangle with the hydraulic diameter of 2.8mm and the aspect ratio of 20. The working fluid is 3–15K subcooled and surface heat flux on the channel is between 0–3.64 kW/m2, among which two-phase instability at low vapor quantity may occur. By using a novel transparent heating technique and a high-speed camera, visualization results are obtained. The parameters are acquired with a National Instruments Data Acquisition card. In the experiments, long-period oscillation and short-period oscillation are observed as the primary types of instability in a microchannel. Instability characteristics represented from signals correspond well with the flow pattern. Moreover, effects of several parameters are investigated. The results indicate that the oscillating period generally increases with the heat flux density and decreases with inlet subcooling, while the effects of inlet resistance are more complex.


2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Swapnil A. Dharaskar ◽  
Kailas L. Wasewar ◽  
Mahesh N. Varma ◽  
Diwakar Z. Shende

A new class of green solvents, known as ionic liquids (ILs), has recently been the subject of intensive research on the extractive desulfurization of liquid fuels because of the limitation of traditional hydrodesulfurization method. In present work, eleven Lewis acid ionic liquids were synthesized and employed as promising extractants for deep desulfurization of the liquid fuel containing dibenzothiophene (DBT) to test the desulfurization efficiency. [Bmim]Cl/FeCl3was the most promising ionic liquid and performed the best among studied ionic liquids under the same operating conditions. It can remove dibenzothiophene from the model liquid fuel in the single-stage extraction process with the maximum desulfurization efficiency of 75.6%. It was also found that [Bmim]Cl/FeCl3may be reused without regeneration with considerable extraction efficiency of 47.3%. Huge saving on energy can be achieved if we make use of this ionic liquids behavior in process design, instead of regenerating ionic liquids after every time of extraction.


Author(s):  
Sheng Wei ◽  
Brandon Sforzo ◽  
Jerry Seitzman

This paper describes experimental measurements of forced ignition of prevaporized liquid fuels in a well-controlled facility that incorporates non-uniform flow conditions similar to those of gas turbine engine combustors. The goal here is to elucidate the processes by which the initially unfueled kernel evolves into a self-sustained flame. Three fuels are examined: a conventional Jet-A and two synthesized fuels that are used to explore fuel composition effects. A commercial, high-energy recessed cavity discharge igniter located at the test section wall ejects kernels at 15 Hz into a preheated, striated crossflow. Next to the igniter wall is an unfueled air flow; above this is a premixed, prevaporized, fuel-air flow, with a matched velocity and an equivalence ratio near 0.75. The fuels are prevaporized in order to isolate chemical effects. Differences in early ignition kernel development are explored using three, synchronized, high-speed imaging diagnostics: schlieren, emission/chemiluminescence, and OH planar laser-induced fluorescence (PLIF). The schlieren images reveal rapid entrainment of crossflow fluid into the kernel. The PLIF and emission images suggest chemical reactions between the hot kernel and the entrained fuel-air mixture start within tens of microseconds after the kernel begins entraining fuel, with some heat release possibly occurring. Initially, dilution cooling of the kernel appears to outweigh whatever heat release occurs; so whether the kernel leads to successful ignition or not, the reaction rate and the spatial extent of the reacting region decrease significantly with time. During a successful ignition event, small regions of the reacting kernel survive this dilution and are able to transition into a self-sustained flame after ∼1–2 ms. The low aromatic/low cetane number fuel, which also has the lowest ignition probability, takes much longer for the reaction zone to grow after the initial decay. The high aromatic, more easily ignited fuel, shows the largest reaction region at early times.


ALCHEMY ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 58
Author(s):  
Hendro Juwono ◽  
Ardita Elliyanti ◽  
Firman Satria Pamungkas ◽  
Anas Assari ◽  
Ahmad Hawky Dermawan ◽  
...  

<p>Liquid fuel from polystyrene waste and waste cooking oil biodiesel was successfully obtained through catalytic cracking using Al-MCM-41/Ceramic. The structure, morphology, acidity, and porosity of the catalyst were studied by SEM-EDX, pyridine FTIR, and N<sub>2</sub> gas adsorption-desorption. The products of catalytic cracking were analyzed using gas chromatogram-mass spectroscopy (GC-MS). The highest yield was obtained at feedstock variations of 57% (P): 43% (M) with the number of hydrocarbon fractions (&lt; C<sub>7</sub>) is 0.48%, hydrocarbon fraction (C<sub>8 </sub>- C<sub>12</sub>) is 20.99%, and hydrocarbon fraction (&gt; C<sub>12</sub>) is 78.53% in the cracking time 1 hours. Physical characteristics were reported in the form of density, flash point, and caloric value respective. The performance of liquid fuels with commercial fuels, Premium (RON 88), and additives of methyl tertiary butyl ether (MTBE) comparisons of 225 (mL): 750 (mL): 18.25 (mL) respectively produce thermal efficiency on engine use gasoline generator sets was 28.22% at the load of 2118 Watts. Based on this research, all variations of feedstock produce liquid fuels that are in accordance with SNI 06-3506-1994 concerning the quality of gasoline fuel types.</p><p> </p>Keywords: Catalytic cracking, polystyrene waste, waste cooking oil, liquid fuel


2019 ◽  
Vol 81 (1) ◽  
pp. 118-128
Author(s):  
V. V. Balandin ◽  
V. V. Balandin ◽  
V. V. Parkhachev

Investigating impact interaction of solid and deformed bodies with obstacles of various physical natures requires developing experimental methodologies of registering the parameters of the interaction process. In experimental investigations of impact interaction of solids, it is common practice to measure displacement of strikers as a function of time, as well as their velocity and deceleration. To determine the displacement and velocity of a striker, a radio-interferometric methodology of registering the displacement of its rear end is proposed. In contrast with the registration methods based on high-speed filming and pulsed X-ray photography, the method using a millimeter-range radio-interferometer provides continuous high-accuracy registering of the displacement of the rear end of a striker in a wide range of displacement values. To test the effectiveness of the methodology, a series of experiments have been conducted on registering the motion of a cylindrical striker of an aluminum alloy, fired from a 20mm-dia gas gun. The displacement of the striker was also monitored using high-speed filming. The results of measuring using the two methodologies differ within the limits of the error of measurement. Based on the results of the above experiments, it has been concluded that the methodology of determining the displacement and velocity of strikers in a ballistic experiment using a mm-range radio-interferometer makes it possible to measure practically continuously large displacements (100 mm and larger) to a safe accuracy. The present methodology can be used for measuring the displacement and velocity of the rear end of a striker interacting with obstacles of various physical natures (metals, ceramics, soils, concretes, etc.).


Author(s):  
Zhi Huang ◽  
Weimin Kan ◽  
Yuxuan Lu ◽  
Ting Cheng ◽  
Liangying Yu ◽  
...  

Increased ignition probabilities of ethanol are found on a heated hot-plate with the introduction of Al2O3, Fe3O4, and carbon nanotube (CNT) nanoparticle suspensions. We show that the mechanism is probably due to liquid fuel boiling point elevation caused by nanoparticle accumulation at liquid–vapor interfaces. The magnitudes of this impact are related to the number and geometry of nanoparticles but independent from the nanoparticle chemical compositions. These findings may have important applications for developing future alternative liquid fuels with advanced combustion characteristics.


2008 ◽  
Author(s):  
Alexander L. Brown ◽  
Sam S. Yoon ◽  
Richard A. Jepsen

We are engaged in efforts to model spray phenomena. Applications of principal interest include the high-speed impact of large vessels of fuel and the subsequent fire, fire suppression, solid propellant fires, pressurized pipe or tank rupture, and fire propagation for cascading liquid fuels. To help guide research and development efforts geared towards designing an appropriate spray modeling capability, a Phenomenon Identification and Ranking exercise was conducted. The summarized results of the exercise in tabular format, a Phenomenon Identification and Ranking Table (PIRT), are presented. The table forms the context for a textual literature review of the existing state of knowledge for modeling applications of interest. This exercise highlights some of the shortcomings in existing tools and knowledge, and suggests productive research activities that can help advance the modeling capabilities for the desired applications. Notable needs exist for research in high Weber number particle-surface impacts, particle collisions, multi-physics couplings, and low void fraction multi-phase coupling.


Sign in / Sign up

Export Citation Format

Share Document