Liquid Spills Research Articles

Influence of ammonia-water fog formation on ammonia dispersion from a liquid spill

Ammonia is expected to play an important role in the green transition, both as a hydrogen carrier and a zero-emission fuel. The use of refrigerated ammonia is attractive due to its relatively high volumetric energy density and increased safety compared to pressurized solutions. Ammonia is highly toxic, and with new applications and increased global demand come stricter requirements for safe handling. Cold gaseous ammonia following a spill of refrigerated ammonia will in contact with humid air cause fog formation. In an environment rich in ammonia, these droplets will due to ammonia’s strong hygroscopicity consist of considerable amounts of liquid ammonia as well as water. Fog formation affects the ammonia-air density and thus influences the dispersion dynamics, with a potentially significant impact on hazardous zones. In this work, we present a CFD model including an ammonia-water fog formation model based on accurate thermodynamics. This includes modeling the vapor–liquid equilibrium and accounting for the exothermic mixing of ammonia and water. We apply this CFD model to relevant cases and demonstrate the significant impact of the fog. We analyze the effect of varying relative humidity, fog visibility, influence of wind, and pool evaporation rate. Finally, we model the Red Squirrel test 1F and show how the fog formation could have influenced the dispersion behavior.

Model-Based PID Tuning Method for a Reactor for Microwave-Assisted Chemistry

This paper presents a model-based PID tuning method for a reactor used in microwave-assisted chemistry. The reactor is equipped with a solid-state source of microwaves and a PID controller capable of increasing or decreasing the delivered microwave power to maintain the reacting substances at the desired temperature. The model has the form of an algorithm applied in numerical simulations of two simultaneous processes: heating a substance by absorbing microwave radiation and cooling it by dissipating heat to the surroundings. It has proven its suitability for tuning the PID controller in a time-efficient manner. Despite some noticeable inaccuracies, the presented approach easily finds PID coefficients that result in stable and repeatable controller operation. In this way, significant time savings can be achieved, as well as minimizing the risks associated with, for example, boiling liquid spills. The article demonstrates that a carefully designed, but still relatively simple, model can yield significant benefits in tuning PID controllers.

Dispersion characteristics of large-scale liquid hydrogen spills in a real-world liquid hydrogen refueling station with various releasing and environmental conditions

The global expansion of hydrogen refueling stations (HRS) has heightened interest in the development of liquid hydrogen refueling stations (LHRS). This study presents a model for an LHRS, inspired by the Yilan HRS in Shanghai, to simulate large-scale liquid hydrogen (LH2) leakage scenarios. Utilizing the FLACS-CFD software, comprehensive simulations were performed to assess the impact of various environmental conditions and leakage parameters—such as wind speed, wind direction, spill rate, and spill duration—on critical outcomes including the size of the LH2 pool, evaporation rate, flammable volume of the vaporized hydrogen gas cloud, and maximum downwind distance/height. The findings establish a correlation between these factors and the predicted results, providing real-time guidance for managing LH2 leakage incidents at operational LHRS.

ИНСТРУМЕНТАРИЙ ОПЕРАЦИОННОЙ ПОДДЕРЖКИ В ОЦЕНКЕ ИНТЕНСИВНОСТИ ТЕПЛОВОГО ИЗЛУЧЕНИЯ ПРИ ПОЖАРЕ В ЗДАНИИ УВЕЛИЧЕННОЙ ОКОННОЙ ПРОЕМНОСТИ

It is shown that the task of taking into account the impact of thermal radiation from a fire for determining safe distances for situating fire engines and choosing positions for firefighters during developing operational fire extinguishing plans for industrial buildings with enlarged window openings is not fully supported by the functionality of existing software systems. Since thermal radiation as one of the components of dangerous fire factors valuable only with a sufficient exposure, we analyze events tree branches associated with the process of diffusion combustion on the surface of a flammable liquid spill. Algorithms of the fire temperature regime module in the room of an industrial building with an enlarged window opening are presented based on an integral model and the module of the directional pattern of thermal radiation through window openings. The results of numerical modeling using the presented software product allow us to conclude that the effect of thermal radiation diaphragmization by window openings weakens with distance from the front of the heat-emitting surface and becomes negligible at distances of five meters and more.

Perioperative complications of using freezing nitrogen ethanol composite to treat bone tumors: Clinical experience from a single center.

The cryoablation efficacy of semisolid freezing nitrogen ethanol composite (FNEC) has been demonstrated. We aimed to investigate the feasibility of adjuvant FNEC-assisted cryoablation in different bone cavity types by assessing the perioperative complication rates. The medical charts of patients who received intraoperative adjuvant cryoablation using semisolid FNEC for bone tumors from December 2013 to January 2018 were reviewed. The bone cavities were categorized into three types according to liquid spill potential (type 1, able to hold liquid without limb manipulation; type 2, required extensive limb manipulation to retain liquid; type 3, unable to retain liquid). The overall complication rate and the complication rates stratified by bone cavity type were determined. Among the 76 patients, 30.3%, 57.9%, and 11.8% had type 1, 2, and 3 bone cavities, respectively. The mean follow-up time for perioperative complications was 43.5 ± 24.1 days. Five patients experienced complications, including two cases of skin damage, two cases of skin infection, and one case of fracture, yielding an overall perioperative complication rate of 6.4%. All cases of skin damage and skin infection were superficial and manageable by oral antibiotics. The patient with a pathologic fracture recovered well after being treated with open reduction and plate fixation. No neuropraxia was noted within the first few days postsurgery in any patient. The complication rates in type 1, 2, and 3 bone cavities were 13%, 4.6%, and 0%, respectively. All bone cavity types had a low incidence of perioperative complications after treatment with adjuvant FNEC-assisted cryoablation. Semisolid FNEC-assisted cryoablation is a feasible alternative to overcome the liquid spill potential in bone cavities resulting from tumor resection and intralesional curettage.

Developing a model of the radiating surface of a flame over a flammable liquid spill in the presence of wind

The object of the study is a spill fire. The subject of the study is the geometric characteristics of the flame, in particular, the length and angle of inclination. The model of the radiating surface of a flame over a burning liquid spill of an arbitrary shape is constructed. The essence of the approach is that the length of the flame at a given point is equal to the length of the flame at the point of the circular spill located at the same distance from the boundary of the spill. It allows generalizing the known empirical dependences for the case of spills of arbitrary shape. The flame length is a power-law function of the distance to the spill boundary and the mass loss rate per unit area. To take into account the effect of wind on the shape of the flame, the empirical dependence of the length and angle of inclination of the flame on the wind speed is used. It is assumed that the wind deforms the flame in such a way that all points of the flame surface deviate by the same angle from the vertical. Wind inclines the flame from the vertical axis more significantly for the smaller size of the spill and smaller mass loss rate per unit area. This is due to the formation of more powerful upward currents over the combustion center when its size and intensity of liquid combustion increase. A model of the radiating surface of the flame was constructed in a parametric form. The results obtained from the model are in good agreement with the experimental ones. The relative error for the angle of deviation of the flame by the wind from the vertical axis does not exceed 9%. In practice, this opens up opportunities for calculating the thermal impact on nearby technological objects, as well as determining safe zones for the location of personnel and equipment involved in fire suppression. The model can be used to specify the thermal effect of fire on steel and concrete structures.

Construction of the stochastic model of thermal radiation from a flammable liquid spill fire

The object of this study is the process of liquid combustion in the pool, and the subject of the study is the characteristics of the random process that describes the heat flow by radiation. Such, in particular, are the law of distribution, mathematical expectation, and correlation function. An experimental study of the combustion of used motor oil in a pool measuring 9.5×8.7 m2 was carried out. The mathematical expectation and variance of the cross-sectional area of the flame were determined by video recording followed by the analysis of individual frames. Testing of the hypothesis about the normal law of distribution of the cross-sectional area showed that with a confidence probability of 0.95, the proposed hypothesis does not contradict the experimental data. A selective correlation function and its approximation in the form of σ2exp(–α|τ|) were constructed. Due to the linear relationship between the cross-sectional area and the heat flux by radiation from the fire, the latter will also have a normal distribution law. At the same time, the magnitude of pulsations (the ratio of the rms deviation to the mathematical expectation) for these random processes will be the same. The value of the parameter α of the correlation function will also be the same. Taking into account the inertial properties of the device for measuring the heat flux density, a comparison of the experimentally measured values of the heat flux density with the calculated ones was carried out. The measurement results fall into the intervals corresponding to the confidence probability of 0.95. At the same time, the maximum deviation between calculated and experimental data is 14 %. From a practical point of view, the built stochastic model opens up possibilities for taking into account random flame pulsations when determining safe zones for the location of personnel and equipment. The model can be used to specify the thermal effect of fire on steel and concrete structures

СОВЕРШЕНСТВОВАНИЕ ПРОГРАММНО-ТЕХНИЧЕСКИХ СРЕДСТВ СИСТЕМ ЦУКС ТЕРРИТОРИАЛЬНЫХ ОРГАНОВ МЧС РОССИИ

The article presents the results of automation of the software and hardware complex, which allows for rapid accounting and analysis of the situation data, as well as forecasting the scale of the consequences of emergencies related to the following events: a spill of flammable liquid, gas leakage from the gas transmission network, the spread of petroleum products, the spread of oil from underwater potentially dangerous objects.

Rayleigh scattering-based single mode-graded index multimode-coreless fiber structure for distributed liquid detection.

Liquid sensing is crucial in numerous industrial contexts, from chemical processing to power transformers, ensuring safety and operational optimization. While electrochemical liquid sensors are common, they pose safety risks, especially when monitoring hazardous liquids. Optical fiber sensors, with advantages like immunity to electromagnetic fields and resistance to chemical corrosion, present a safer alternative. These sensors are primarily used for detecting pipeline oil leakages and liquid level sensing. However, current sensors face challenges in detecting liquid spills across multiple locations and require improved spatial resolution. This paper presents what we believe to be a novel single mode-graded index multimode-coreless fiber sensing structure that directly interacts with liquids. Integrated with a distributed optical fiber sensing system, this sensor can detect liquid droplets with high precision, as demonstrated by the successful identification and size estimation of four consecutive oil droplets. Our approach offers an innovative solution for distributed liquid droplet detection and it paves the way for industrial liquid detecting applications.

A Sustainable Method for Removal of the Full Range of Liquid and Solid Hydrocarbons from Water Including Up- and Recycling.

Beyond their CO2 emittance when burned as fuels, hydrocarbons (HCs) serve as omnipresent raw materials and commodities. No matter if as liquid oil spills or the endless amounts of plastic roaming the oceans, HCs behave as persistent pollutants with water as main carrier to distribute. Even if their general chemical structure [-(CH2 )n -] is quite simple, the endless range of n leads to contaminations of different appearances and properties. A water remediation method based on superparamagnetic iron oxide nanoparticles (SPIONs) modified with self-assembled monolayers of alkyl phosphonic acid derivatives is presented. These molecules enable the SPIONs to non-covalently bind HCs, independently from the molecular weight, size and morphology. The attractive interaction is mainly based on hydrophobic and Coulomb interaction, which allows recycling of the SPIONs. The superparamagnetic core allows a simple magnetic collection and separation from the water phase which makes it a promising addition to wastewater treatment. Agglomerates of collected plastic "waste" even exhibit superior adsorption properties for crude oil, another hydrocarbon waste which gives these collected wastes a second life. This upcycling approach combined with presented recycling methods enables a complete recycling loop.

Экспериментальное исследование теплообмена в межстенном пространстве криогенного резервуара с порошковой изоляцией

Currently, double-wall cryogenic non-isothermal tanks with vacuum-powder or vacuum-multilayer insulation are used in storage and transportation of such cryogenic liquids as liquid nitrogen, oxygen and liquefied natural gas. If the inner vessel is disrupted, the liquid spills into the heat-insulating space and evaporates as a result of heat inflow from the environment. This increases pressure in the thermal insulation space. To ensure functioning of the tank, it is necessary to limit pressure increase in the heat-insulating space. Results of experiments on evaporation of the liquid nitrogen entering the space filled with powder insulation were presented (expanded perlite was considered in the experiments). Experiments were carried out on a laboratory model simulating the tank heat-insulating space. Nature of the cryogenic liquid distribution in the powder insulation volume was determined, possibility of the cryogenic liquid direct contact with the walls of the tank was shown, and the tank walls temperatures and the cryogenic products evaporation intensity over time were determined. Based on the work results, physical and mathematical model of the emergency process development in the interwall space of a cryogenic tank associated with violation of the inner vessel tightness and subsequent spill of cryogenic liquid into the heat-insulating space was refined

The Mutual Effect Study of Horizontal and Vertical Loads on the Elastic Tank Partially Filled with Liquid

Modern equipment elements in the energy, chemical industry, transport, aviation, and space engineering work under conditions of increased technological loads, at high temperatures and pressure levels. At the same time, the equipment is usually exposed to external loads of various natures. Hydroelastic phenomena must also be taken into account in designing and modernizing tanks and storage facilities for flammable and combustible substances. Flammable and combustible liquid accumulation leads to the increased environmental and fire hazard of such objects. The possible dangerous liquid leakage and tank depressurization negatively affect the surrounding area environment state. A fire in the tank is one of the most dangerous emergencies that could lead both to significant material and environmental damage and to human casualties. The paper treats the environmental hazards reducing problem from liquid hydrocarbon spills from storage tanks, which lead to destructive effects on all environment components especially during emergency situations. It has been established for sufficiently thin tank elastic walls, the fundamental frequency during coupled oscillations could be much lower than the frequency of the fluid in the shell with rigid walls. As the thickness of the tank wall increases, this effect becomes insignificant, and the lower oscillation frequency of the shell with liquid approaches the oscillation frequency of the liquid in a rigid tank. Parametric resonance and sub-resonance effects have been treated.

Numerical modeling of liquid spills from the damaged container and collision of two rising bubbles in partially filled enclosure using modified Volume-Of-Fluid (VOF) method

In the present work, two crucial shortcomings associated with Volume-Of-Fluid (VOF) model namely: (1) spurious interface smearing arising from false-diffusion errors, and (2) non-physical velocity fluctuation across the physical discontinuities, are systematically addressed, aiming to establish a unique methodological foundation and guidelines for the enhancement of interface-capturing techniques in handling multi-fluid flows. To accomplish this objective, first, a novel third-order bounded convection scheme is derived based on the Normalized Variable Diagram and Total Variation Diminishing concepts (NVD-TVD) and is then applied for the discretization of the volume-fraction equation. To cope with the instability issue induced by pressure fluctuation, the standard version of the implicit non-iterative PISO algorithm is first modified by incorporating the third pressure-correction step into the algorithm and is then utilized for the treatment of the pressure-velocity coupling. A feasibility and applicability of the proposed modifications in dealing with violent free-surface and multi-fluid flows are demonstrated against the five different challenging benchmark cases including two-dimensional dam-break flow over the dry bed, oil spill from the damaged container, single bubble rising, merging of two rising bubbles and two-fluid Rayleigh-Taylor Instability problems. The comparison of the obtained results with previously published literatures vividly corroborates the robustness and versatility of the modified VOF model in handling multi-fluid flows involving interface coalescence and breakup events. In the last staged, three new benchmark solutions namely (1) coalescence of two consecutive bubbles inside the partially filled enclosure, (2) two-dimensional three-fluid Rayleigh-Taylor Instability, and (3) oil/water spilling from the damaged tank are analyzed using the verified VOF method, aiming to provide a high-quality validation data for CFD simulations.

Theoretical modeling of diffusion clouds of liquid hydrogen spilling in crosswind field with atmospheric inversion layer

A theoretical model was developed to predict the diffusion process of hydrogen clouds in a crosswind field with an atmospheric inversion layer in this work to evaluate the safety of liquid hydrogen spills. The theoretical model was verified by the experimental results carried out by NASA. The results show that the maximum deviation of diffusion cloud centerline heights of the theoretical model and experiments is 8.92%. The mechanism of the inversion layer suppressing cloud rise is revealed from the theoretical model, atmospheric temperature gradient is closely related to the air density gradient. Compared to the case without atmospheric inversion layer, the cloud height decreases by 2.60%, 5.22%, and 8.70% and the cloud concentration increases by 6.20%, 12.78%, and 22.30% for the temperature gradient of 0.03, 0.06 and 0.10 K/m, respectively. The velocity of crosswind is 1.7 m/s, 2.7 m/s, 3.6 m/s, and 6.0 m/s in the temperature gradient of 0.10 K/m inversion layer environment, the height of the cloud is 34.77 m, 24.05 m, 16.83 m, and 11.16 m, and the hydrogen concentrations of the cloud centerline are 10.22%, 13.67%, 17.54%, and 28.92%, respectively. Therefore, it is significant to consider the crosswind field and atmospheric inversion layer for liquid hydrogen diffusion.

Experimental Study on Boiling Vaporization of Liquid Hydrogen in Nonspreading Pool

Research on the boiling vaporization process of liquid hydrogen spilled on solid ground is very important for the safety risk assessment of liquid hydrogen. Since the main source of the heat flux in the vaporization process comes from the ground, the heat flux from the ground into the liquid pool should be studied in-depth. In this paper, the boiling vaporization process of liquid hydrogen on the surface of concrete is studied. The analysis of the boiling process of a liquid pool is conducted by utilizing the boiling curve and historical temperature data collected in close proximity to the surface of the concrete. It was found that the boiling regime of a liquid hydrogen pool on the concrete surface presents non-uniformity, and the film boiling of liquid hydrogen on the concrete surface ended earlier than the results calculated by boiling regime correlations. When the measured temperature in the experiment indicates a transition from film boiling to the transition boiling, the temperature difference between the thermocouple temperature measured at a depth of 2 mm and the boiling point of liquid hydrogen is 130 K higher than the predicted superheat of the minimum heat flux (MHF). In the later stage of the experiment, the average relative error between the experimental value of the vaporization rate and the predicted value of the model is 7.48%. This research advances the understanding of heat transfer between concrete ground and a liquid hydrogen pool. In addition, the experimental data obtained in this study contributes to improving the source term model for safety analysis of liquid hydrogen spills.

Red Squirrel Tests: Air Products' ammonia field experiments

AbstractThe Red Squirrel ammonia field experiments were conducted at the DNV Spadeadam site in the UK in 2022. Field test data currently exists for high‐pressure (ambient temperature) two‐phase releases of ammonia from Desert Tortoise (1983) and FLADIS (1996) experiments. No field tests have ever been done for cold (refrigerated) ammonia liquid spills on dry land or into water. The handling of liquified ammonia, during storage/processing and transportation, in a cold (refrigerated) state is inherently safer than in a high‐pressure (ambient temperature) liquified state. The main objective of the Air Products’ Red Squirrel Tests was to determine the source term and dispersion characteristics for high‐pressure (ambient temperature) liquified ammonia and low‐pressure (cold/refrigerated) liquified ammonia in form of two‐phase releases and liquid spills, respectively. Liquid spills on concrete and water were studied, along with the process conditions that led to the transition from liquid spills to two‐phase flow regimes based on discharge pressures for cold liquified ammonia. Details on the equipment, instrumentation, secondary containment, and ammonia sensors and their layout are presented. An initial analysis of the source terms and dispersion behavior for two‐phase releases and contained liquid spills over a range of weather conditions is also provided.

Numerical Simulation of Liquid Hydrogen Spilling in the Confined Cabin with Air Supplying and Vent

The purpose of this work is to research the spill and diffusion characteristics of liquid hydrogen in confined cabin with air supplying and vent. The spill and diffusion behavior of liquid hydrogen in the confined cabin with air supplying and vent was simulated using Fluent software. The feasibility of the model was verified by the experimental results. The research results show that the numerical simulation model can simulate to predict the diffusion process of liquid hydrogen well and has application value for engineering. The diffusion cloud after the spill of liquid hydrogen is gathering at the top and slowly spread to the surrounding which is different from the open environment. The process of liquid hydrogen spill can be divided into three stages, among which the concentration of cloud clusters changes sharply in the spilling stage. Low wind speed can affect the inclination angle of the diffuse cloud, and it is concluded that wind speed is also the main factor affecting the movement of the diffusion cloud. The research results are expected to provide a reference for standard formulation and design of liquid hydrogen applications.

Preprogramming Floating Time of Liquid Marble

AbstractNon‐sticking droplets wrapped with fine hydrophobic particles, namely liquid marbles, can be transported both on solid and water pool without an undesired spill of the inner encapsulated liquid. While the stimuli‐responsive release of the inner liquid in the target area is proposed, the time‐programmed release is not yet achieved. Herein, the hydrophobicity of nanoclay is modulated via a catalyst‐free 1,4‐conjugate addition reaction to form liquid marbles. This nanoclay liquid marble is robust and stable in air but collapses on the liquid pool with a specific lifetime. The lifetime of the liquid marble can be modulated over seconds to hours scale depending on the selection of chemically modulated wettability of the nanoclay. The critical mechanism of lifetime modulation is responsible for controlling the coalescence kinetics between the water pool and inner liquid by nanoclays’ high diffusion length and chemically varied water spreading potential. The NC liquid marble's programmable lifetime to ‘time‐bomb’ type drug release and cascade chemical reaction is applied—without requiring any external intervention.

Simulations for Planning of Liquid Hydrogen Spill Test

In order to better understand the complex pooling and vaporization of a liquid hydrogen spill, Sandia National Laboratories is conducting a highly instrumented, controlled experiment inside their Shock Tube Facility. Simulations were run before the experiment to help with the planning of experimental conditions, including sensor placement and cross wind velocity. This paper describes the modeling used in this planning process and its main conclusions. Sierra Suite’s Fuego, an in-house computational fluid dynamics code, was used to simulate a RANS model of a liquid hydrogen spill with five crosswind velocities: 0.45, 0.89, 1.34, 1.79, and 2.24 m/s. Two pool sizes were considered: a diameter of 0.85 m and a diameter of 1.7. A grid resolution study was completed on the smaller pool size with a 1.34 m/s crosswind. A comparison of the length and height of the plume of flammable hydrogen vaporizing from the pool shows that the plume becomes longer and remains closer to the ground with increasing wind speed. The plume reaches the top of the facility only in the 0.45 m/s case. From these results, we concluded that it will be best for the spacing and location of the concentration sensors to be reconfigured for each wind speed during the experiment.

Preparation of environment-friendly SiO2 aerogel based on waste boron mud and its adsorption behavior for toluene.

To mitigate the environmental hazards of boron mud waste accumulation, we prepared environmental-friendly SiO2 aerogels by extracting them through alkaline leaching treatment and optimized the experimental conditions. The optimum process parameters for alkaline leaching solution NaOH concentration, leaching temperature, solid-to-liquid ratio, and leaching time were 2 mol/L, 95 °C, 1:4, and 3 h, respectively. In this work, cheap and non-toxic hydroxy silicone oil (PDMS-OH) and hydrogen-containing silicone oil (PMHS) were used as surface modifiers instead of toxic and expensive trimethylchlorosilane (TMCS) in the SiO2 aerogel modification process. The best performance under the optimum conditions was achieved with 60% PDMS-OH-modified SiO2 aerogel. Organic liquid spills, represented by toluene, pose a great danger to the environment and water bodies. We treated free toluene on the water surface with the aerogel mentioned above and its adsorption capacity was up to 2,655 mg/g. After the adsorption of toluene, the aerogels coalesced into agglomerates for subsequent collection and handling. Furthermore, after five repeated applications, the adsorption capacity remained at 91.43% of the initial application. Overall, this research provided an inexpensive and simple solution for the treatment of organic liquids in wastewater.