Natural Vents Research Articles

Numerical study on the fluid flow and condensation heat transfer characteristics of two-phase NaCl-H2O fluids on the external swept spiral coil in a hydrothermal vent

The substantial thermal energy of two-phase NaCl-H2O hydrothermal fluids makes them a significant target for utilizing deep-sea energy. A fundamental understanding of the thermal performance of two-phase NaCl-H2O hydrothermal fluids during condensation is crucial for heat energy harnessing. It aims to obtain the flow and condensation heat transfer characteristics of two-phase NaCl-H2O fluids during the heat transfer process outside a spiral coil structure in this paper. The properties of the NaCl-H2O binary systems were adopted instead of pure water, and the salt transport equation was considered to reflect the impact of salinity change on heat transfer, making the simulation more representative of natural venting fluids. The results indicated a significant tangential velocity when the fluids externally swept the spiral coil. Secondly, the heat transfer area can be divided into the “normal region” and the “island region,” of which convection and condensation contribute to the heat transfer mechanisms. The “island region” formation was attributed to both vapor condensation and the spoiler effect caused by the spiral structure. Moreover, the heat flux increased with decreasing salinity in the “island region,” and a weak interaction was observed between heat flux and salinity in the “normal region.” Finally, the spiral structure's heat transfer performance was superior to the straight structure's. This investigation may provide a basis for designing and optimizing the heat transfer equipment for deep-sea hydrothermal extraction.

Osmotic energy conversion in serpentinite-hosted deep-sea hydrothermal vents

Cells harvest energy from ionic gradients by selective ion transport across membranes, and the same principle is recently being used for osmotic power generation from salinity gradients at ocean-river interfaces. Common to these ionic gradient conversions is that they require intricate nanoscale structures. Here, we show that natural submarine serpentinite-hosted hydrothermal vent (HV) precipitates are capable of converting ionic gradients into electrochemical energy by selective transport of Na+, K+, H+, and Cl-. Layered hydroxide nanocrystals are aligned radially outwards from the HV fluid channels, constituting confined nanopores that span millimeters in the HV wall. The nanopores change the surface charge depending on adsorbed ions, allowing the mineral to function as a cation- and anion-selective ion transport membrane. Our findings indicate that chemical disequilibria originating from flow and concentration gradients in geologic environments generate confined nanospaces which enable the spontaneous establishment of osmotic energy conversion.

Green Solutions in the Fire Safety Strategy within a Medical Centre

This study investigates the behaviour of the hot gas temperature and associated smoke numerically in case of fire inside a medical centre. Fire Dynamics Simulator (FDS), provided by NIST, has been used to run the simulations for all proposed cases. Different solutions are suggested to reduce the severity of the hot gas temperature and smoke thickness, in case of fire inside the building. Among all investigated solutions, natural ventilation can do the best job. A mechanical fan is also an option, but not as good as a natural vent found at the top of the building. Natural ventilation can offer cheap and clean solutions to improve the safety level and environmental conditions inside the building, which offers an appropriate evacuation process for firefighters and civilians inside the building.

Mixing of endogenous CO2 and meteoric H2O causes extremely efficient carbonate dissolution

Karst corrosion of carbonate rocks by water with dissolved gases proceeds in most cases along two major scenarios: (i) meteoric water absorbs CO2 from soil and atmosphere, or (ii) ascending water of deep circulation carries with it dissolved endogenous gases, mainly CO2 and H2S. We have observed a peculiar variant where meteoric water absorbs ascending endogenous gases at a natural gas vent on a travertine mound in Slovakia. Carbonate dissolution's extreme effectiveness is demonstrated by mineralization of rainwater ponded at a gas vent, rising to 3.2 g/L of dissolved solids shortly after the rainfall. One liter of water ponded at the vent and mixing with the venting gas, dissolved up to 800 mg of calcium at a rate exceeding 5.8 mg/L·min. Limestone tablets placed at the vent show signs of significant corrosion, at rates up to 126 mm/ka. The rate is comparable to those in coastal karst, where freshwater is mixing with seawater and to those in sulfuric acid speleogenesis (SAS), both the highest hitherto known rates of karst corrosion in carbonates. The geomorphic effects of the process described are depressions on the surface of travertine near the vents of endogenous CO2. This type of corrosion seems to be universal and probably occurs everywhere where endogenous CO2 is exhaled to the surface from carbonate rocks.

Chemical and olfactometric inventory of gaseous spot vents in Mt. Amiata volcanic-geothermal area (Italy)

Geothermal areas are typically characterised by the presence of gases and odours in the background atmosphere, stemming from natural emissions and possible mining exploitation of the area. This study presents the first olfactometric investigation of endogenous gas emissions from natural and archaeo-industrial vents in a geothermal area. Mt. Amiata is known for its complex geology and historical cinnabar mining. This study offers an inventory of spot gas emissions, not only in terms of odour and chemical concentration but also including flux data, a ground-breaking achievement in this field. The primary challenge of this investigation was estimating the emitted flow from ground holes or mine entrances, posing the risk of hazardous anoxic conditions. To address this challenge, an innovative and adaptive approach was adopted. The main breakthrough method involved the adaptation of a balometer, typically employed for indoor ventilation systems, to measure the flow of endogenous gases. Field surveys revealed odour concentrations that can exceed 106 of ouE/m3, surpassing industrial emission level considerably. Chemical concentrations, primarily consisted of CO2 (80/90 %v/v) and CH4 (∼10%v/v), providing critical insights into the global warming potential (GWP) associated with natural emissions. Moreover, these spots, often located at ground level and lacking a substantial atmospheric dilution, pose potential risks to nearby individuals, with concentrations of gases such as H2S surpassing safety thresholds. Total emissive flux of the investigated spot vents in the Mt. Amiata area, showed that the emission rate of H2S is notably substantial (55 kg/h), roughly equivalent to emissions from approximately four 20 MW geothermal plants, as along with odour emission rates in the order of 107 ouE/s. Considering the GWP derived from emitted gases, the total inventory assessment of the spot vents resulted in 36 t/h or 23 t/h CO2eq, depending on the time horizon considered (GWP20 or GWP100 respectively).

Performance-Based Design Assessment of Temperature Tenability Condition in a Hotel Atrium

Fire safety risk assessment to prevent loss of human life and property is necessary for complex structures where the traditional prescriptive designs are inapplicable. Maintaining tenable temperature conditions is essential for the safe evacuation of building occupants. This study considered British Standards (BS) 7974 and the Code of Practice for Fire Precautions in Buildings to analyze the temperature tenability conditions in the hotel atrium through a performance-based design approach. Further, the Computational Fluid Dynamics (CFD) code, Pyrosim, a Graphical User Interface (GUI) of the Fire Dynamics Simulator (FDS), was utilized to simulate a constant Heat Release Rate (HRR) steady state design fire of 5 Megawatts (MW) igniting from the hotel brasserie (ground floor) within the atrium. The researcher used the big design fire of 5MW to generalize the results to similar fires in similar structures. The objective was to conduct a fire safety risk assessment to prevent loss of property and fatalities by activating a smoke management control system with a ‘what if’ condition when the fire suppression system failed to start. Temperature data was collected through the statistical steady state profile, smoke layer temperatures, thermocouples, and 2-dimensional slice temperature recordings. The ground floor, the fire source, was found to have untenable conditions for human survival with temperatures above 2250C, as confirmed by thermocouple and steady-state temperature profile readings. Other floors demonstrated tenable conditions for human survival with temperatures below 400C due to the effect of natural vents and mechanical extractors, which extracted the hot smoke at a rate of 15m/s. The temperature recordings from this study compared well with those from Chew and Liew’s (2000) Computational Fluid Dynamics results, which had fire igniting within the atrium, without sprinklers, and had mechanical extraction fans and a constant Heat Release Rate of 5 Megawatts (MW). The results indicated that the smoke control management system maintained tenable temperature conditions within the hotel atrium, even without the fire suppression system through sprinklers. Considering the design fire size was 5 MW, which was significantly big, the results could be generalized for other hotels or structures with similar designs.

Microbial associates of an endemic Mediterranean seagrass enhance the access of the host and the surrounding seawater to inorganic nitrogen under ocean acidification

Seagrasses are important primary producers in oceans worldwide. They live in shallow coastal waters that are experiencing carbon dioxide enrichment and ocean acidification. Posidonia oceanica, an endemic seagrass species that dominates the Mediterranean Sea, achieves high abundances in seawater with relatively low concentrations of dissolved inorganic nitrogen. Here we tested whether microbial metabolisms associated with P. oceanica and surrounding seawater enhance seagrass access to nitrogen. Using stable isotope enrichments of intact seagrass with amino acids, we showed that ammonification by free-living and seagrass-associated microbes produce ammonium that is likely used by seagrass and surrounding particulate organic matter. Metagenomic analysis of the epiphytic biofilm on the blades and rhizomes support the ubiquity of microbial ammonification genes in this system. Further, we leveraged the presence of natural carbon dioxide vents and show that the presence of P. oceanica enhanced the uptake of nitrogen by water column particulate organic matter, increasing carbon fixation by a factor of 8.6–17.4 with the greatest effect at CO2 vent sites. However, microbial ammonification was reduced at lower pH, suggesting that future ocean climate change will compromise this microbial process. Thus, the seagrass holobiont enhances water column productivity, even in the context of ocean acidification.

The role of hydrodynamics for the spatial distribution of high-temperature hydrothermal vent-endemic fauna in the deep ocean environment

Active hydrothermal vents provide the surrounding submarine environment with substantial amounts of matter and energy, thus serving as important habitats for diverse megabenthic communities in the deep ocean and constituting a unique, highly productive chemosynthetic ecosystem on Earth. Vent-endemic biological communities gather near the venting site and are usually not found beyond a distance of the order of 100 m from the vent. This is surprising because one would actually expect matter ejected from high-temperature vents, which generate highly turbulent buoyancy plumes, to be suspended and carried far away by the plume flows and deep-sea currents. Here, we study this problem from a fluid dynamics perspective by simulating the vent hydrodynamics using a numerical model that couples the plume flow with induced matter and energy transport. We find that both low- and high-temperature vents deposit most vent matter relatively close to the plume. In particular, the tendency of turbulent buoyancy plumes to carry matter far away is strongly counteracted by generated entrainment flows back into the plume stem. The deposition ranges of organic and inorganic hydrothermal particles obtained from the simulations for various natural high-temperature vents are consistent with the observed maximum spatial extent of biological communities, evidencing that plume hydrodynamics exercises strong control over the spatial distribution of vent-endemic fauna. While other factors affecting the spatial distribution of vent-endemic fauna, such as geology and geochemistry, are site-specific, the main physical features of plume hydrodynamics unraveled in this study are largely site-unspecific and therefore universal across vent sites on Earth.

Experimental investigation on effect of fire source location on compartment fire phenomena with a single natural ceiling vent

ABSTRACT The effect of fire source location (FSL) on compartment fire phenomena with a single natural ceiling vent was experimentally investigated under various vent area (VA) and heat release rate (HRR) conditions. Two FSL cases, where the fire source was located at the centre (FSLC) and on the side (FSLS) of the floor, were tested. In the bidirectional vent flow patterns of FSLC and FSLS, the detailed locations where the smoke outflow and the fresh air inflow occurred were different. Empirical correlations were proposed for predicting the smoke outflow areas. FSLC exhibited a higher central velocity of the outflow, larger estimated mass flow rate of the outflow, and lower temperatures inside the compartment than FSLS. The estimated mass flow rate of the outflow depended more on VA than on HRR. A previous correlation was more suitable for FSLS than FSLC in predicting the mass flow rate of the outflow.

Molybdenum in basalt-hosted seafloor hydrothermal systems: Experimental, theoretical, and field sampling approaches

Seafloor hydrothermal vents represent potential sources of Mo and other biologically relevant transition metals to the global ocean, complementing continental runoff. Here, we use a combination of experimental, theoretical, and field-sampling approaches to investigate the behavior of Mo in basalt-hosted seafloor hydrothermal systems to provide insight into the processes controlling Mo concentrations in hydrothermal fluids and to derive estimates of vent fluid Mo concentrations and fluxes. Results of this study demonstrate that reaction fluids generated from 350 °C, 500 bar hydrothermal basalt alteration experiments contain 775–801 nmol/kg Mo and are thus comparable to a recently collected time series of natural seafloor vent fluids that contained 200–220 nmol/kg Mo at 302 °C and 29–30 nmol/kg at 281–282 °C (Evans et al., 2023). Synchrotron-based analyses of experimentally altered basalt produced in this study and additional natural samples of altered oceanic crust originally collected from Pito Deep Rift reveal the presence of Mo-rich particles consistent with trace molybdenite. Comparisons of Mo:Cu ratios in natural vent fluids and near-vent sediment trap samples from Main Endeavour Field indicate that vent fluid Mo is readily incorporated into buoyant plume particles and advected out of the near-vent field, analogous to previous mass balance studies of Cu in this region.Thermodynamic calculations of molybdenite solubility in the context of mineral-buffered hydrothermal fluids and comparisons with natural and experimental hydrothermal fluids suggest that high-temperature vent fluids contain 30–1500 nmol/kg Mo. While a minor component of the modern Mo budget, hydrothermal Mo fluxes are estimated to have constituted 0.3–200× the contemporaneous continental weathering fluxes prior to the ∼2.4 Ga ago “Great Oxidation Event” and widespread oxidative continental weathering. Overall, identification of hydrothermal vents as a source of Mo-rich plume particles with potential for dispersal into the wider marine environment has significant implications for hypotheses regarding the co-evolution of Life and Earth’s environments, specifically the form and availability of Mo in anoxic Archean-Eon oceans, where Mo-dependent enzymatic pathways are thought to have emerged and subsequently evolved.

An inventory of greenhouse gas emissions due to natural gas pipeline incidents in the United States and Canada from 1980s to 2021

Natural gas is believed to be a critical transitional energy source. However, natural gas pipelines, once failed, will contribute to a large amount of greenhouse gas (GHG) emissions, including methane from uncontrolled natural gas venting and carbon dioxide from flared natural gas. However, the GHG emissions caused by pipeline incidents are not included in the regular inventories, making the counted GHG amount deviate from the reality. This study, for the first time, establishes an inventory framework for GHG emissions including all natural gas pipeline incidents in the two of the largest gas producers and consumers in North America (United States and Canada) from 1980s to 2021. The inventory comprises GHG emissions resulting from gathering and transmission pipeline incidents in a total of 24 states or regions in the United States between 1970 and 2021, local distribution pipeline incidents in 22 states or regions between 1970 and 2021, as well as natural gas pipeline incidents in a total of 7 provinces or regions in Canada between 1979 and 2021. These datasets can improve the accuracy of regular emission inventories by covering more emission sources in the United States and Canada and provide essential information for climate-oriented pipeline integrity management.

Experimental Study on the Smoke Temperature Decrease near Natural Vents Induced by Air Entrainment in a Tunnel Fire

Previous studies have shown that there is a large difference in the temperature of smoke in the upstream and downstream of a vertical shaft, but no quantitative study on the subject has been conducted. In this paper, a model experimental test was conducted to study the effect of a natural vertical shaft on the distribution of smoke temperature in tunnel fires. A laser sheet was used as an assisting tool to show the smoke flow field. A series of tests were conducted with shaft heights varying from 0.2 m to 1.2 m and a heat release rate (HRR) of 9 kW, 17 kW, 29 kW, and 65 kW. The entrainment phenomenon around the vertical shaft was analyzed, and the results showed that the amount of fresh air entrainment is the main reason for the temperature decrease in upstream and downstream smoke temperatures. Based on the experimental results, an empirical model for predicting the amount of fresh air entrainment and a prediction model of the downstream smoke temperature were proposed, and the predicted values are in good agreement with the experimental values.

Simulation on venting process and valve opening control method for gas trunk pipelines

Determining the venting time of a gas trunk pipeline segment provides an important basis for formulating an emergency plan in the advent of unexpected accidents. As the natural gas venting process corresponds to the transient flow, it is necessary to establish a transient hydraulic-thermal simulation model in order to determine the venting time. In this paper, based on two kinds of venting scenarios in which there is only one venting point in the venting system of a gas trunk pipeline segment—namely, where the venting point is either at one of the two ends or at the junction of two gas trunk pipeline segments—transient hydraulic-thermal simulation models are established. The models consist of gas flow governing equations, the gas state equation, gas physical property equations, initial conditions, and appropriate boundary conditions. The implicit central difference method is used to discretize the gas flow partial differential equations, and the trust-region-dogleg algorithm is used to solve the equations corresponding to each time step, in order to dynamically simulate the whole venting process. The judgment condition for the end of the venting process is that the average pressure of gas trunk pipeline segment is less than 0.11 MPa (actual pressure). Comparing the simulation results of the proposed model with those of the OLGA software and real operational data, we find that the venting time error is less than 10%. On this basis, a venting valve opening control principle is proposed, which prevents the venting noise from exceeded the specified noise value (85 dB) in the venting design of domestic gas pipeline projects. The established calculation model for venting time (dynamic simulation model) for a gas trunk pipeline segment and the proposed opening control principle of venting valve provide reference for the optimal operation of gas pipeline venting systems.

Evaluation of fire smoke and heat exhaust performance of shafts by natural venting in tunnels

Theoretical analysis and numerical simulations are performed to study the smoke and heat exhaust performance of natural venting system with different shaft forms. Based on the mass conservation for the gas flow in the shaft, equations for estimating the total gas mass flow rate are derived. The methods for determining the smoke and heat exhaust efficiencies are also proposed. A numerical model is built for series of CFD simulations considering different shaft forms (length–width ratio of shaft vent and shape). The results clearly present the details of the natural venting process by displaying the temperature and velocity fields. The boundary layer separation and plug-holing phenomena are also observed. The effects of the shaft shapes on the smoke and heat exhaust efficiencies have been discussed quantitatively. It is highlighted that when the cross-sectional area of shaft is constant, a smaller length–width ratio of the shaft vent leads to higher smoke and heat exhaust efficiencies. Moreover, the smoke and heat exhaust efficiencies of cylindrical shafts are higher than those of cubic ones. The findings of this paper could provide some principles for the design of natural ventilation shaft in urban tunnels. For example, the length–width ratio of shaft vent less than 1:3 is recommended for the design of natural venting system in tunnels.

Mineralogy of the coal waste dumps from the Czech part of the Upper Silesian Basin: Emphasized role of halides for element mobility

Both unburning and burning coal mine dumps present serious hazards to the natural environment and human health. Bituminous coal has been produced in the Czech part of the Upper Silesian Basin since 18th century, with total production over 100 million metric tons of waste material (barren rock) deposited in dumps. Today, each dump has undergone remediation and reclamation works, and many of them were totaly removed. Only three dumps with signs of thermal activity (burning) remain, with the Heřmanice dump as the most important. The powder X-ray diffraction (XRD) in combination with electron dispersive spectroscopy (EDS) and backscattered electron (BSE) imaging were applied to identify and describe the products of both unburning and burning dumps. The ones without thermal activity released mostly sulfates such as jarosite group minerals, hexahydrite, ferrohexahydrite, gypsum, thenardite, konyanite, and baryte due to pyrite weathering processes, accompanied by ferrihydrite, schwertmannite, goethite, and aragonite. As expected, the mineral associations of thermally active dumps were more variable. Apart from hot gas vent products such as sulfur, salammoniac, and cryptohalite, we identified a zoned sulfate cap (crust) with an accumulation of newly formed phases (e.g., aluminopyracmonite, pyracmonite, godovikovite, mascagnite, koktaite, boussingaultite, and clairite). Both the gas vents and sulfate crust contained a number of rare and exotic phases, such as Bi, bismuthinite, demicheleite-(Br), demicheleite-(I), fluorite, selenium, NH4Br, NH4I, BiOCl, BiBr3, BiI3, native iodine, CdS, CdIn2S4, (NH4,K)AlF4, (NH4,K)3AlF6, Ce-dominant REE-sulfate, and others. Since coal ash and barren rock are not geochemicaly anomalous, the presence of such various phases could be atributed to the very effective leaching and transport of chemical elements by halide elements, which originated in brines in the roof of the Carboniferous rocks circulating in the strata prior to extraction and emplacement in the dump. This mineralization is to a great extent similar to that of natural volcanic vents, and must be studied by specific methods (low-vacuum electron microscopy with energy-dispersive detectors, use of natural unpolished samples). The composition of altered rock clasts within the dumps was monitored only occasionally, but newly formed feldspars (probably sanidine, albite, andesine), hematite, diopside to hedenbergite, cordierite, magnetite-magnesioferrite minerals, anhydrite, TiO2 microcrystals, Mg-rich fayalite, and in case of more intensively burnt rocks also wollastonite, barium feldspar (celsian-hyalophane series), and a phase of Ca-SiO4-PO4 system were also observed. It is clear that the burning of coal dumps presents a specific problem, and future steps towards understanding their potential environmental risks would require complex studies including the determination of their mass and chemical element balance, the estimation of the dump volume affected by the thermal mobilization of chemical elements, and the migration pathways of the potentially-hazardous elements. However, it is clear that the most problematic part incudes just the few uppermost meters with vents of hot gases and the sulfate cap, which are readily soluble in water after the end or lateral shift of burning.

Testing Filter-Based Air Cleaners with Surrogate Particles for Viruses and Exhaled Droplets

Indoor air cleaners can contribute to reducing infection risks by the filtration of virus-carrying droplets. There are various national standards to test indoor air cleaners that determine the clean air delivery rate (CADR), but typically only as a size-integrated value for particles > 0.3 μm. Thus, a test method using potassium chloride (KCl) and paraffin as surrogate particles in the size range of viruses and exhaled droplets was developed. We show that air cleaners with fibrous and electrostatic filters are generally capable of reducing the airborne particle concentrations. However, for electret filters, the performance can strongly degrade over time by being loaded with particles. By comparing filters with different efficiencies in the same air cleaner, we demonstrate that the use of high-efficiency filters can be even at the expense of the cleaning efficacy. We developed a mathematical model to estimate the inhaled dose of viruses and show that the combination of natural venting and an air cleaner can lead to a substantial reduction of the infection risk.

Attic ventilation and radiant heat barriers in naturally ventilated galvanized metal-Roofed buildings

ABSTRACT The study's uniqueness stems from its goal of determining the efficacy of natural attic vents and radiation heat barriers on galvanized metal roof buildings in lowering attic and indoor air temperatures for thermal comfort in a humid tropical climate, a topic that has received little attention in previous research. This was accomplished by utilizing three separate experimental situations using two tiny models of single-sloped zinc-roofed houses, each with varied attic ventilation openings and radiant heat barrier applications. The thermal conditions of the attic and occupant rooms in the ventilated test cell tended to be cooler than in the unventilated one in the first experiment, which compared a test cell with 20% ventilation apertures in the attic to another test cell without ventilation. The second experiment, which compared a test cell with 10% attic ventilation to another test cell (without attic ventilation) with radiant heat barrier application, found that the radiant heat barrier's effect on temperature reduction was generally better. The third experiment, which compared a test cell with 20% attic ventilation to a test cell without attic ventilation but with radiant heat barrier application, revealed that attic ventilation outperformed the radiant heat barrier in terms of temperature reduction.

Effects of water spray on smoke layer in buildings with natural venting

Fire safety is always an important issue in the indoor and built environment. There might be hidden conflicts among different systems such as suppression and smoke control. The effect of water spray on smoke movement in halls with natural venting system is reported in this paper. A series of scale modelling experiments were carried out to study the temperature variation under water spray. A small vent on the opposite side of fire source would intensify smoke stratification and result in a higher smoke temperature. Water spray would weaken the smoke stratification due to the cooling effect on the smoke and the downward drag on the smoke layer. The temperature development of smoke was the result of competition of these two effects on the smoke layer. When the effect of water spray was stronger, the average smoke temperature tended to be lower, and the temperature difference of the ceiling to the smoke layer interface was smaller. When the effect of the opening dominated, the results were reversed. These results would be useful for providing fire safety in indoor and built environment.

Comparative Analysis of Satellite and Regulatory based Gas Flare Volumes in the Niger Delta Region

Associated gas flaring leads to severe environmental issue, and the importance of effective monitoring and accurate recording of this operation has been a subject of discussion in the petroleum industry. This research used statistical methods to compare the flare volume of both Regulatory Agency records and Satellite-based estimates to determine the accuracy and reliability of estimates. Seven prolific offshore oilfields from the Niger Delta region were considered for this research and the monthly records of flare volume for 2016, 2017, 2020 and 2021 were used to investigate the comparative relationship that exists. The result revealed that the mean flare volumes of four oilfields (Agbara, Bonga, Erha and Usan) did not differ significantly but Abo and Akpo oilfields revealed that estimates from the satellite were significantly greater than the regulatory reports, while the estimates from Agbami oilfield supported the contrast. The Pearson correlation analysis also revealed that a moderately strong positive relationship exists between the estimates for the sampled oilfields. The study further examined the discrepancies between both methods of gas flare measurements and proffered solutions on how these discrepancies could be resolved and recommended a strategy for monitoring natural gas venting.

Vibration characteristics analysis and structural improvement of natural gas venting ignition pipeline

In order to study the flow-induced vibration characteristics of the natural gas vent pipeline under the internal flow field, taking the gas transmission station pipeline as an example, the ANSYS Workbench software was used to establish models under two working conditions, uncoupling and fluid-solid coupling, for modal analysis, and analyze and compare the calculation results and propose a structural improvement plan. The results show that the maximum amplitude of the first three modes under the two working conditions is concentrated on the riser mouth, and the amplitude under the fluid-solid coupling condition is slightly larger than that of no coupling; the inner diameter of the pipe elbow is large and the pressure is small, and the outside diameter is small and the pressure is small. Large, this instability will increase the air pulsation of the flow field. In the improved scheme, adding a restriction on the top to increase the rigidity of the pipeline can significantly reduce the maximum amplitude of the gas pipeline; adding an orifice to eliminate air flow pulsation has a certain effect on reducing the maximum amplitude and natural frequency, and the combination of the two can make the pipeline more stable. The research results of this paper can provide improved ideas for vibration reduction at the natural gas venting operation site.