scholarly journals Peculiarities of development and extinguishing fires at the objects where liquified petroleum gas is stored

2019 ◽  
Vol 29 (2) ◽  
pp. 124-126
Author(s):  
Yu. Yu. Dendarenko ◽  
V. I. Dyven ◽  
Ye. O. Tyshchenko ◽  
O. D. Blashchuk
Keyword(s):  
High Speed ◽  
Flame Temperature ◽  
Active Phase ◽  
Physical Object ◽  
Liquefied Petroleum Gas ◽  
Gaseous State ◽  
Air Jets ◽  
Water Jets ◽  
Thermal Screen ◽  
Steel Tank

The possibility of using sprayed water jets is established, primarily radial air jets, in vertical and horizontal planes in order to reduce the temperature of the burning Liquefied Petroleum Gas, starting from the cut-off of its expiration into free space. Various technical means of supplying water in a spray and spray nozzles for their creation, which are used in solving the problem of reducing the temperature of the burning Liquefied Petroleum Gas are viewed. It has been established that the active phase of the sprayed water jet is most effective (0,5-0,75 of the lengths), which, acting under the cut of the flame is crushed to a finely dispersed phase under the influence of a high-speed gas jet. As can be seen from the above, the heating rate of the finely dispersed water phase is increased up to the gaseous state, which leads to a decrease of the temperature of the flame in its middle combustion zone. Consequently, in the flame temperature will be much lower than the temperature of the flame cone, and, as a result, close to the extinction temperature. The authors recommend the use of modern jet-forming devices to realize this goal – nozzles NRT-5, NRT-10, NRT-20, NRS, as well as hand nozzles of the kind RSK-50, RS-А, RS-B, PROTEK. In order to cool, for example, one horizontal ground steel tank on both sides, it is necessary to use at least two hydraulic guns, which will act as maneuvering. In this case, the flow of water from the hydraulic gun with a diameter of the nozzle 25 mm will be from 16 to 18 liters per second. Therefore, the task is to find, calculate and experimentally prove the efficiency of the thermal screen, which is created in the form of a moving water surface that can effectively protect a particular physical object from the thermal impact of the heat zone. In order to reduce the flow of water to cool the tanks, the authors suggest using the NRS to create radial (flat) water jets. Application of such a nozzle allows to increase the area of simultaneous cooling of the maximum surface area per unit time due to the expansion of the angle of the spray jet spark. The water consumption does not exceed 13 liters per second.

SURFACE ENHANCEMENT—BRINGING IT ALL TOGETHER

1977 ◽  
Vol 1977 (1) ◽  
pp. 347-354
Author(s):  
Jack E. Wilson
Keyword(s):  
High Speed ◽  
Oil Spills ◽  
Cost Effective ◽  
Stationary Mode ◽  
Open Area ◽  
Surface Enhancement ◽  
Air Jets ◽  
Water Jets ◽  
Surface Active Agents ◽  
System Data

ABSTRACT Pursuit of a concept as simple as reversing the oil spill spreading phenomenon has resulted in the development of a very effective methodology for cleaning up U.S. Navy oil spills. New equipment and techniques are now routinely used throughout the Navy where spills occur. Two comprehensive spill cleanup scenarios which extensively utilize the surface enhancement equipment and techniques are described. The two scenarios are: (1) confined area spill, with the skimmer in a stationary mode; and (2) open area spill, with the skimmer in a moving mode. The confined area stationary mode scenario employs boat propeller wash, air and water jets remote to the skimmer, surface active agents, granular or chip sorbents, and water and air jets built into the skimmer/boom system. Data is presented which shows that skimmer performance can be improved by factors of 8 and 18 for water and air enhancement systems respectively. The open area moving mode scenario employs a skimmer with boom and two utility boats in a “V” configuration with granular sorbents, piston film, etc., or a skimmer with oil concentration sweeps having built-in water jets and with granular sorbents, piston films, etc. Examples are presented which clearly show that low speed skimming (under 2.5 knots) while utilizing surface enhancement techniques is more cost effective than high speed skimming, even if 80% throughput efficiencies could be achieved.

scholarly journals Research on the Ignition Height and Reaction Flame Temperature of PTFE/Al/Si/CuO with Different Mass Ratios of PTFE/Si

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3464
Author(s):  
Xuan Zou ◽  
Jingyuan Zhou ◽  
Xianwen Ran ◽  
Yiting Wu ◽  
Ping Liu ◽  
...  
Keyword(s):  
Energy Release ◽  
High Speed ◽  
Flame Temperature ◽  
Sintering Process ◽  
Release Process ◽  
Reactive Material ◽  
Temperature Changes ◽  
Release Capacity ◽  
Mass Ratios ◽  
The Relationship

Recent studies have shown that the energy release capacity of Polytetrafluoroethylene (PTFE)/Al with Si, and CuO, respectively, is higher than that of PTFE/Al. PTFE/Al/Si/CuO reactive materials with four proportions of PTFE/Si were designed by the molding–sintering process to study the influence of different PTFE/Si mass ratios on energy release. A drop hammer was selected for igniting the specimens, and the high-speed camera and spectrometer systems were used to record the energy release process and the flame spectrum, respectively. The ignition height of the reactive material was obtained by fitting the relationship between the flame duration and the drop height. It was found that the ignition height of PTFE/Al/Si/CuO containing 20% PTFE/Si is 48.27 cm, which is the lowest compared to the ignition height of other Si/PTFE ratios of PTFE/Al/Si/CuO; the flame temperature was calculated from the flame spectrum. It was found that flame temperature changes little for the same reactive material at different drop heights. Compared with the flame temperature of PTFE/Al/Si/CuO with four mass ratios, it was found that the flame temperature of PTFE/Al/Si/CuO with 20% PTFE/Si is the highest, which is 2589 K. The results show that PTFE/Al/Si/CuO containing 20% PTFE/Si is easier to be ignited and has a stronger temperature destruction effect.

scholarly journals Study of an array of two circular jets impinging on a flat surface

2018 ◽  
Vol 32 ◽  
pp. 01021
Author(s):  
Ştefan-Mugur Simionescu ◽  
Nilesh Dhondoo ◽  
Corneliu Bălan
Keyword(s):  
High Speed ◽  
Solid Wall ◽  
Flow Characteristics ◽  
Navier Stokes ◽  
Vortical Structures ◽  
Air Jets ◽  
Circular Jets ◽  
2D Flow ◽  
Rans Modeling ◽  
Two Jets

In this study, the flow characteristics of an array of two circular, laminar air jets impinging on a smooth solid wall are experimentally and numerically investigated. Direct visualizations using high speed/resolution camera are performed. The evolution of the vortical structures in the area where the jet is deflected from axial to radial direction is emphasized, as well as the interaction between the two jets. A set of CFD numerical simulations in 2D flow domains are performed by using the commercial software Fluent, in the context of Reynolds-averaged Navier-Stokes (RANS) modeling. The numerical resultsare compared and validated with the experiments. The vorticity number is computed and plotted at two different positions from the jet nozzle, and a study of its distribution gives a clue on how the jets are interacting with each other in the proximity of the solid wall.

scholarly journals Behavior of the Erosion-Standoff-Distance Curves for High-Speed Water-Jets in Air.

1993 ◽  
Vol 59 (559) ◽  
pp. 707-712
Author(s):  
Hitoshi Soyama ◽  
Masayuki Shintani ◽  
Toshihiko Uchida ◽  
Jiro Higuchi ◽  
Risaburo Oba
Keyword(s):  
High Speed ◽  
Standoff Distance ◽  
Water Jets

An experimental and simulation study of the flow pattern characteristics of water jet impingements in boreholes

2021 ◽  
pp. 014459872110520
Author(s):  
Yabin Gao ◽  
Xin Xiang ◽  
Ziwen Li ◽  
Xiaoya Guo ◽  
Peizhuang Han
Keyword(s):  
High Speed ◽  
Impact Force ◽  
Jet Impingement ◽  
Flow Patterns ◽  
Water Jet ◽  
Solid Boundary ◽  
Force Model ◽  
Water Jets ◽  
Contact Surfaces ◽  
The Impact

Hydraulic slotting has become one of the most common technologies adopted to increase permeability in low permeability in coal field seams. There are many factors affecting the rock breaking effects of water jets, among which the impact force cannot be ignored. To study the influencing effects of contact surface shapes on jet flow patterns and impact force, this study carried out experiments involving water jet impingement planes and boreholes under different pressure conditions. The investigations included numerical simulations under solid boundary based on gas–liquid coupling models and indoor experiments under high-speed camera observations. The results indicated that when the water jets impinged on different contact surfaces, obvious reflection flow occurred, and the axial velocity had changed through three stages during the development process. Moreover, the shapes of the contact surfaces, along with the outlet pressure, were found to have impacts on the angles and velocities of the reflected flow. The relevant empirical formulas were summarized according to this study's simulation results. In addition, the flow patterns and shapes of the contact surfaces were observed to have influencing effects on the impact force. An impact force model was established in this study based on the empirical formula, and the model was verified using both the simulation and experimental results. It was confirmed that the proposed model could provide important references for the optimization of the technical parameters water jet systems, which could provide theoretical support for the further intelligent and efficient transformation of coal mine drilling water jet technology.

Investigation of LNG Underwater Release and Combustion Behavior on Water Surface

2021 ◽  
Vol 73 (04) ◽  
pp. 35-36
Author(s):  
Chris Carpenter
Keyword(s):  
Wind Tunnel ◽  
Water Surface ◽  
High Speed ◽  
Volume Flow Rate ◽  
Flame Temperature ◽  
Pressure Gauge ◽  
Water Line ◽  
Accidental Release ◽  
Combustion Behavior ◽  
Offshore Technology

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 30646, “Experimental Investigation of LNG Underwater Release and Combustion Behavior on the Water Surface,” by Yixiang Zhang, Jianlu Zhu, and Youmei Peng, China University of Petroleum, et al., prepared for the 2020 Offshore Technology Conference, originally scheduled to be held in Houston, 4-7 May. The paper has not been peer reviewed. Copyright 2020 Offshore Technology Conference. Reproduced by permission. Most liquefied natural gas (LNG) is transported by ship, creating opportunities for potential hazards to surrounding devices and the environment. Nevertheless, few studies have examined the characteristics of LNG underwater leakage and subsequent vapor flame. The paper considers transportation safety and risk evaluation for LNG, with emphasis on accidental release and vapor flame. Introduction The cryogenic nature of LNG, with a boiling point of -162°C, raises safety concerns with regard to vaporization gas hazards and the potential for pool fires. According to the literature devoted to LNG accidental release and spill, three puncture positions have been proposed: Category I, where the leakage point is above the water line; Category II, where the point is at or close to the water line; and Category III, where the point is below the water line. A need exists to investigate LNG underwater leakage and combustion behavior for risk assessment. This work focuses on experimental research of the dynamic behavior of LNG jet release under water and the immediate burning on the water surface using three orifices and different crosswinds. The main points of investigation include the following: - Liquid-rising process and microbehavior in the orifice - Flame geometry on the water surface under crosswinds - Flame-temperature distribution on the water surface Experimental Setup Experimental Facilities. Experiments were conducted in a rectangular tank measuring 1000 mm long, 500 mm wide, and 500 mm high, which was placed in a wind tunnel. The nozzles have diameters of 1, 3, and 5 mm in the middle of the discharge pipe. An inline cryogenic flow-meter with a measuring range of 0.06 - 0.6 m3/h was used to regulate the volume flow rate with an accuracy of 1.5 %. The pressure measurements were performed by a pressure gauge with a range from 0 to 4 MPa placed on the end of the discharged pipeline. The LNG jets were re-leased vertically into the bulk water at a depth of 0.6 m. Images were recorded using a high-speed video camera system. Experimental Conditions. The window was closed when LNG was released, and the discharged gas was quickly diffused from the wind tunnel. The temperature in the room was 17±1°C and 14±0.5°C in water. The relative humidity was approximately 50%. All tests were conducted three times.

Spatio-Temporal Distribution of Soot Temperature for Flames Using Optical Pyrometry Under Unsteady Inlet Airflow Conditions

2016 ◽  
Author(s):  
Arda Cakmakci ◽  
Michael Knadler ◽  
Jong Guen Lee
Keyword(s):  
Temperature Fluctuation ◽  
High Speed ◽  
Flame Temperature ◽  
Temperature Response ◽  
Local Temperature ◽  
Soot Temperature ◽  
High Speed Camera ◽  
Unsteady Combustion ◽  
Inlet Velocity ◽  
Multi Wavelength

Two pyrometric tools for measuring soot temperature response in fuel-rich flames under unsteady inlet airflow conditions are developed. High-speed pyrometry using a high-speed color camera is used in producing soot temperature distributions, with its results compared with those of global soot temperature response measured using a multi-wavelength pyrometer. For the former, the pixel RGB values pertaining to respective bandwidths of red, green and blue filters are used to calculate temperature and for the latter, the emission from whole flame at 660 nm, 730 nm and 800 nm is used to measure temperature. The combustor, running on Jet-A fuel, achieves unsteady inlet airflow using a siren running at frequencies of 150 and 250 Hz and with modulation levels (RMS) 20–50% of mean velocity. Spatiotemporal response of flame temperature measured by the high speed camera is presented by phase-averaged with average subtracted images and by fast Fourier transform at the modulation frequencies of inlet velocity. Simultaneous measurement of combustor inlet air velocity and flame soot temperature using the multi-wavelength pyrometer is used in calculating the flame transfer function of flame temperature response to unsteady inlet airflow. The results of global temperature and temperature fluctuation from the 3-color pyrometer show qualitative agreement with the local temperature response measured by the high speed camera. Over the range of operating conditions employed, the overall flame temperature fluctuation increases linearly with respect to the inlet velocity fluctuation. The two-dimensional map of flame temperature under unsteady combustion determined using a high-speed digital color camera shows that the local temperature fluctuation during unsteady combustion occurs over relatively small region of flame and its level is greater (∼10–20%) than that of overall temperature fluctuation (∼1%).

Comparative study on interfacial oscillations of rectangular and elliptical liquid jets

2020 ◽  
Vol 234 (7) ◽  
pp. 1272-1286 ◽  
Author(s):  
Amin Jaberi ◽  
Mehran Tadjfar
Keyword(s):  
Aspect Ratio ◽  
Weber Number ◽  
High Speed ◽  
Nozzle Geometry ◽  
Liquid Jets ◽  
High Speed Photography ◽  
Aspect Ratios ◽  
Water Jets ◽  
Switching Phenomenon ◽  
Axis Switching

The instability characteristics and flow structures of water jets injected from rectangular and elliptical nozzles with aspect ratios varying from 2 to 6 were experimentally studied and compared. Shadowgraph technique was employed for flow visualization, and structures on the liquid jet surface were captured using high speed photography. It was found that disturbances originating from the nozzle geometry initially perturbed the liquid column, and then, at high jet velocities, disturbances generated within the flow dominated the jet surface. It was also found that rectangular nozzles introduced more disturbances into the flow than the elliptical ones. The characteristic parameters of axis-switching phenomenon including wavelength, frequency, and amplitude were measured and compared. Axis-switching wavelength was found to increase linearly with Weber number. Also, the wavelengths of rectangular jets were longer than the elliptical jets. Further, the frequency of axis-switching was shown to be reduced with increase of both Weber number and aspect ratio. It was observed that the axis-switching amplitude increased monotonically, reached a peak, and then decreased gradually. It was also found that the axis-switching amplitude varied with Weber number. At lower values of Weber number, the rectangular nozzles had higher amplitude than the elliptical nozzles. However, at higher values of Weber number, this relation was reversed, and the elliptical nozzles had the higher axis-switching amplitudes. This reversal Weber number decreased with the orifice aspect ratio. The reversal Weber number for aspect ratio of 4 was about 289, and it had decreased to 144 for the aspect ratio of 6.

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