Surface Of Tank Research Articles

Методика определения термопрочности топливного бака орбитальной ступени с маршевым жидкостным ракетным двигателем

The present work is devoted to the development of engineering techniques for assessing the explosion of the space launch vehicle orbital stages, after turning off the main liquid propulsion engine, located in a circular orbit at altitudes of 200-1000 km. It is supposed that the unused residue of liquid propellant component in the propellant tank is vaporized by the impact on the structure of the pro¬pellant tank space factors, thus increasing the vapor pressure propellant to values exceeding the design strength of the pro¬pellant tank. Under the current outer space factors mean thermal effect on the orbital stage of the during its orbital motion (direct solar radiation, reflected from the Earth’s solar radiation, the Earth’s own radiation and aerodynamic heat flux). During the practical calculation it is solved a number of problems: the definition of the maximum (finding the orbital stage entirely in the lighted orbit) and the minimum (presence of maximum shaded portion of the orbit) limit of the thermal loading of the propellant orbital stage; the determination of the pressure of the vaporized propellant component vapor in the tank orbital stage (depending on the mass and the boundary conditions of the liquid propellant component placement residue); evaluation of strength tank design orbital stage by increasing its temperature and increased internal pressure caused by the evapora¬tion of the propellant component residue. To assess the explosion of the propellant tank orbital stage of the space launch vehicle with the main liquid propellant engine it is analysed the criteria in the form of ratios of ring voltage of a propellant tank structure to the value of the tensile strength, while the corresponding values of the lower and upper boun-daries of the thermal load. The calculations showed average values of absorbed heat flux at maximum thermal loading (the pro-pellant tank surface is exposed to the total direct solar radiation, reflected from the Earth’s solar radiation, intrinsic radiation of the Earth and aerodynamic heat flux throughout the orbit) and minimum thermal loading (the propellant tank surface orbital stage is in Earth’s shadow). The pre¬sence of residual unused liquid oxygen tank into the space launch vehicle “Zenit” in an amount up to 3 % of the initial filling of the tank does not contribute to exposure.

SU‐D‐BRC‐07: System Design for a 3D Volumetric Scintillation Detector Using SCMOS Cameras

Purpose:The purpose of this project is to build a volumetric scintillation detector for quantitative imaging of 3D dose distributions of proton beams accurately in near real‐time.Methods:The liquid scintillator (LS) detector consists of a transparent acrylic tank (20×20×20 cm3) filled with a liquid scintillator that when irradiated with protons generates scintillation light. To track rapid spatial and dose variations in spot scanning proton beams we used three scientific‐complementary metal‐oxide semiconductor (sCMOS) imagers (2560×2160 pixels). The cameras collect optical signal from three orthogonal projections. To reduce system footprint two mirrors oriented at 45° to the tank surfaces redirect scintillation light to cameras for capturing top and right views. Selection of fixed focal length objective lenses for these cameras was based on their ability to provide large depth of field (DoF) and required field of view (FoV). Multiple cross‐hairs imprinted on the tank surfaces allow for image corrections arising from camera perspective and refraction.Results:We determined that by setting sCMOS to 16‐bit dynamic range, truncating its FoV (1100×1100 pixels) to image the entire volume of the LS detector, and using 5.6 msec integration time imaging rate can be ramped up to 88 frames per second (fps). 20 mm focal length lens provides a 20 cm imaging DoF and 0.24 mm/pixel resolution. Master‐slave camera configuration enable the slaves to initiate image acquisition instantly (within 2 µsec) after receiving a trigger signal. A computer with 128 GB RAM was used for spooling images from the cameras and can sustain a maximum recording time of 2 min per camera at 75 fps.Conclusion:The three sCMOS cameras are capable of high speed imaging. They can therefore be used for quick, high‐resolution, and precise mapping of dose distributions from scanned spot proton beams in three dimensions.

Evaporation mitigation by floating modular devices

Prolonged periods of drought and consequent evaporation from open water bodies in arid parts of Australia continue to be a threat to water availability for agricultural production. Over many parts of Australia, the annual average evaporation exceeds the annual precipitation by more than 5 times. Given its significance, it is surprising that no evaporation mitigation technique has gained widespread adoption to date. High capital and maintenance costs of manufactured products are a significant barrier to implementation. The use of directly recycled clean plastic containers as floating modular devices to mitigate evaporation has been investigated for the first time. A six-month trial at an arid zone site in Australia of this potential cost effective solution has been undertaken. The experiment was performed using clean conventional drinking water bottles as floating modules on the open water surface of 240-L tanks with three varying degrees of covering (nil, 34% and 68%). A systematic reduction in evaporation is demonstrated during the whole study period that is approximately linearly proportional to the covered surface. These results provide a potential foundation for robust evaporation mitigation with the prospect of implementing a cost-optimal design.

Coupled simulation of nonlinear ship motions and a free surface tank

This paper investigates the coupled nonlinear dynamics of a vessel with a free surface tank onboard. To this end, a 6-DOF ship motions simulation code is coupled with a CFD solver addressing the behaviour of the fluid in the tank. The nonlinear ship motions code is of the blended (hybrid) type, intended for the simulation of free running vessels in waves. The nonlinear CFD solver is a GPU-based 3D Weakly-Compressible Smoothed-Particle Hydrodynamic (WCSPH) solver. Numerical results are presented for the nonlinear roll motion of a vessel with and without a free surface tank in regular beam waves with different steepnesses. Nonlinear phenomena are identified and discussed.

Hydrazine vapor inactivates Bacillus spores

NASA policy restricts the total number of bacterial spores that can remain on a spacecraft traveling to any planetary body which might harbor life or have evidence of past life. Hydrazine, N2H4, is commonly used as a propellant on spacecraft. Hydrazine as a liquid is known to inactivate bacterial spores. We have now verified that hydrazine vapor also inactivates bacterial spores. After Bacillus atrophaeus ATCC 9372 spores deposited on stainless steel coupons were exposed to saturated hydrazine vapor in closed containers, the spores were recovered from the coupons, serially diluted, pour plated and the surviving bacterial colonies were counted. The exposure times required to reduce the spore population by a factor of ten, known as the D-value, were 4.70±0.50h at 25°C and 2.85±0.13h at 35°C. These inactivation rates are short enough to ensure that the bioburden of the surfaces and volumes would be negligible after prolonged exposure to hydrazine vapor. Thus, all the propellant tubing and internal tank surfaces exposed to hydrazine vapor do not contribute to the total spore count.

Movement and control of evaporating droplets released from an open surface tank in the push–pull ventilation system

Push–pull ventilation systems are effective local ventilation methods to control airborne contaminants generated in industrial buildings, among which droplets are typical. In this paper, the numerical simulations of water droplets released from an open surface tank into the push–pull flow field are carried out and the effects of ambient relative humidity and the pull-flow velocity on the ventilation system performance are discussed based on the droplet evaporation and movement. It was found that the movement and evaporation of droplets were closely related to the push–pull flow mechanism and the droplet initial diameter. When the control effect was good due to the presence of air closure in the flow field (pull-flow velocity ranging from 1.5 m/s to 3.0 m/s), droplets were unlikely to move away from the closure and the evaporation of droplets smaller than 40 μm was obvious. Whereas when the control effect was poor (pull-flow velocity equaling 1.0 m/s), large droplets still moved around the tank surface but small droplets were subject to dispersing, and in such a case droplets smaller than 60 μm evaporated obviously. Moreover, the effect of ambient relative humidity (ranging from 0 to 80%) on controlling droplets was rather limited and no more than ±6%. In addition, the system could save airflow rate and energy consumption by reducing the pull-flow velocity which was excessive originally in ventilation design. Finally, the paper put forward a new index to evaluate the control effect from another standpoint based on whether the droplets did harm to the environment.

Energy Harvesting from Ammonia Gas Treatment Tank in Organic Fertilizer Powder Plant

This paper proposes an ammonia monitoring system that harvests energy to operate in a chicken manure fertilizer plant. The harvesting is done via thermoelectric generators (TEGs) and photovoltaic (PV) cells. The TEGs convert heat energy on the surface of an air treatment tank into electrical energy by using the Seebeck effect. Since the temperature on the surface of the tank is not high, the TEGs can supply low-power loads. The other loads in the proposed system are powered by the PV cells. Energies obtained from TEGs and PV cells are stored in a supercapacitor (SC) and two lithium batteries, respectively. According to our experiment, the maximum power consumption used by the system was 644mW, while the maximum harvested energy was 4.4W on a sunny day. Together with our developed power management mechanism, our experiment showed that the harvested energies could supply enough energy for a device to run continuously while being able to detect abnormal level of ammonia correctly.

变压器绕组振动特性研究

在理论分析影响变压器绕组振动各因素的基础上，利用ANSYS建立变压器有限元模型仿真分析，验证了不同的预紧力大小对绕组振动固有频率的影响。利用变压器振动在线监测系统，对变压器油箱表面测得的振动信号进行了研究，实验验证了变压器绕组振动主要集中在基频100 Hz处，且基频幅值与负载电流的平方满足正比例关系。 On the basis of theoretical analysis of various factors affecting the vibration of transformer windings, the finite element model simulation analysis of the transformer was built by ANSYS. The effect of different precompression on the natural frequency of winding vibration was verified. The vibration signal of the transformer tank surface was studied by the on-line monitoring system of the transformer vibration. The experimental results showed that the vibration of the transformer windings was concentrated in the fundamental frequency 100 Hz. The amplitude of the fundamental frequency was proportional to the square of load current.

ЕКСПЕРИМЕНТАЛЬНЕ ВИЗНАЧЕННЯ ВИПАРОВУВАННЯ КИСНЮ У ЦИЛІНДРИЧНОМУ БАКУ РАКЕТИ-НОСІЯ В НАТУРНИХ УМОВАХ

Study relates to rocket engine liquid oxygen fuel systems. The evaporation of oxygen was determined in ~5 long cylindrical tank. Experiments were taken under natural conditions. The tank was fuelled with boiling oxygen. The tank pressurization during flight was done with hot helium. It was input into tank as centralized jet with ~180 m/sec speed and mass average temperature ~500K. The total avg-integral aerodynamic heat flow into oxygen ~16 KWt/sq.m. The inner tank surface is waffled (mechanical milling). The gas temperature in free tank volume was measured in 25 spots using rods. The amount of free volume in tank was determined using fuel usage control system. The oxygen upper layer temperature inside the tank reaches the saturated vapour temperature by the middle of the flight when the absolute gas pressure is 1.3-1.5 bar. Oxygen evaporation insignificant speed was determined during engine working time (less than 1kg/sec). The correlation between evaporation speed and the value of aerodynamic heat flow was not determined. The likely reason is tank inner waffled surface and the presence of the power cone. The highest evaporation speed was measured in the beginning of the pressurization system functioning. The hot helium flow interacts with oxygen surface at that time. The necessity to decrease helium input speed was shown.

Humidity effect on the calibration of discharge coefficients of critical flow Venturi nozzles in a pVTt facility

The available research on the humidity effect when calibrating the discharge coefficients of critical flow Venturi nozzles has mostly treated the humid air as a mixture of vapor and dry air. In this paper, atmospheric air with normal humidity was used to calibrate the discharge coefficients of critical flow Venturi nozzles in a pVTt facility. The calibration results were found to depend on the initial pressure in the collection tank, which reduced the discharge coefficient by 1.17%. The results suggest that vapor condensation in the diffuser section of the CFVN and the inventory volume or collection tank and adsorption of water molecules on the surface of the collection tank are additional humidity effects in a pVTt facility. An empirical model was developed for the humidity effect with the critical pressure for each facility determined from the experimental results. With the humidity correction, the NIM and PTB results compare very well.

Comparative evaluation of sizing of metal hydride (MH) hydrogen storage tank filled with different alloys

ABSTRACTThis study presents a comparative analysis of sizing of metal hydride tank filled with different alloys. Alloys include solid solutions and intermetallic compounds of the generic families AB5, AB2, AB, A2B. The effects of the different alloys on the sizing of metal hydride hydrogen storage tanks are complicated and depend on many factors. In this paper, a thermoeconomic optimization analysis with a simple algebraic formula was presented for the estimation of optimum metal hydride tank surface area for heat transfer enhancement. The optimum area of the metal hydride tank filled with commercially available different alloys (LaN5, Ti0,98Zr0,02V0,43Fe0,09Cr0,05Mn1,5, TiFe, Mg2NiH4) was evaluated and compared by the developed method. The optimum net savings and the value of payback were determined for four alloys. It is found that mathematical model can be employed for the determination of optimum metal hydride tank design and increasing net savings according to alloy types. The optimum areas of the tanks filled with four alloys (LaN5, Ti0,98Zr0,02V0,43Fe0,09Cr0,05Mn1,5, TiFe, Mg2NiH4) were calculated as 0.136, 0.130, 0.133, and 0.173 m2, respectively. The optimum net savings for tanks filled with four alloys (LaN5, Ti0,98Zr0,02V0,43Fe0,09Cr0,05Mn1,5, TiFe, Mg2NiH4) are about 461.0, 409.3, 419.6, and 979.6 $ and the values of payback are about 1.98, 2.1, 2.17, and 1.37 years, respectively. Excessive area of the metal hydride tank would not be as economical as the optimum tank area. Thermal management of metal hydride tank must be designed for optimum points calculated at which maximum savings occur.

Physicochemical Characterization of Sludge Originating from Vegetable Oil–Based Cutting Fluids

Vegetable oil–based cutting fluids are a relatively recent development in large-scale metal machining. A metal machining factory in Wales that switched from mineral oil-based to vegetable oil-based cutting fluids has experienced the occurrence of a problematic floating sludge within the settling and holding tanks at the on-site effluent treatment plant. Physicochemical analyses have found that the sludge is composed of on average 33% water, 20% oleic acid, and 18% palmitic acid, originating from the vegetable oil–based cutting fluids used at the factory. A solvent separation step was devised and used successfully to separate water inherent within the sludge so as to study the division of the inorganic elements within the water and organic phases of the sludge. It was found that only a minor constituent of the sludge can be accounted for by Ca-bonded fatty acids. Formation of the sludge is suspected to be due to the biologically induced hydrolysis and oxidation of the oils from esters to the free fatty acids and subsequent creaming, forming a layer of stable floating sludge on the surface of the effluent storage tanks.

Reduction of vibration noise for amorphous metal alloy core distribution transformer

To understand the vibration noise behaviors of amorphous metal alloy core distribution transformer (AMACDT), a 10 kVA prototype was tested under no-load and short-circuit conditions, respectively. The vibration characteristics were described when rated voltage was applied to the secondary side, and the primary side was connected with different load resistances. The largest amplitude positions on the upper bracket and tank surfaces were recorded by vibration sensors arranged on the surface. A data-acquisition platform was set up for signal measurement. The vibration amplitude related to frequency was discussed, and experimental results indicated that the position with the largest amplitude accrued in the middle of the upper bracket and tank surface, at phases a and c, respectively. The experimental results suggest that magnetostrictive and electrodynamic forces play a major role in exciting the vibration noise. At the same time, some rib-reinforcements were welded on the upper bracket and tank surfaces to lessen the vibration energy, which reduced the noise.

The Comparative Study of PD Detecting in Power Transformer Model According to Acoustic Emission and IEC270 Standard Method

This paper presents a comparative study of partial discharge (PD) detection technique of power transformer model. The acoustic emission (AE) method was applied to detect the signal from PD-origin in a model of the power transformer tank according to IEEE standard C57.127. The Time Difference of Arrival (TDOA) technique was additionally applied. In the experiment, a simulated PD-origin was set up inside the transformer tank. Four acoustic sensors were installed on the tank surface, which were used to detect and provide the signal to a signal amplifier and data recorder. Multifunction Compact NI-DAQ 9223 was used together with 1 slot Chassis model 9191 in order to transfer the data to computer by using LAN or wireless system. The AE signal of PD-origin was then collected and analyzed with the Lab View program to identify the location of PD-origin. All physical dimensions of power transformer such as width, length and height and position of each acoustic sensor (in centimeters) were loaded into the main program. Then, the pattern of PD-origin was simulated at different positions in oil-filled transformer tank model. Finally, the localization result was displayed in a graphic user-interface screen. The acquired signal from this method was subsequently compared with the conventional PD detection method using IEC60270 standard in order to observe the PD. The experimental results were satisfactory and could be applied practically.

Simulation Study on HST Distribution for ONAN Oil-Filled Transformer

Advanced monitoring system and preventive maintenance introduced on serviced transformer successfully reducing the equipment malfunction and breakdown rate. However, faults that occur and developed inside the transformer can be very unpredictable. One of the measures can be taken is to analyse the hottest spot temperature (HST) of the transformer, because high temperature will affect transformer insulation system performance and its life-span. HST distribution study on the transformer surface body can give better understanding on how HST will behave at inner and outer transformer surface tank, so that it can be correlated to the actual temperature inside the transformer. Therefore, this paper presents a simulation study on 100 KVA ONAN oil-filled type of distribution transformer with three types of HST intensity. Result shows that temperature distribution projectile is tending to go upwards in the insulation oil and inward into the winding. Moreover, location of HST can be identified by comparing the temperature distribution plot with and without HST.

The effect of environmental conditions on the operation of a hydrogen refuelling station

In this study, the effect of environmental conditions on plant operation was investigated for hydrogen refuelling stations with an external storage facility. Hydrogen storage pressure with respect to tank surface temperatures have been measured and used to create empirical equations for each tank showing the effect of surface temperature on the tank pressure. A physical model of the hydrogen storage tanks has been created in DesignBuilder (EnergyPlus) to simulate the surface temperature of tanks throughout the course of a year with respect to location, site orientation, tank size and surface colour, shading and operating pressure. Finally, the effect that environmental conditions may have on a plant operation is assessed through the prediction of pressure dependent events, namely the frequency of alarms and pressure relief occurrences and hours of plant downtime over the course of a year. The modelling results indicate that location, tank size, surface colour and sunshade can have substantial impacts on the plant operation, whereas the influence of site orientation is less significant. Frequency of pressure dependant events increase as the tank size decreases due to more significant heat gain observed with higher surface-to-volume ratios. Simulation results also prove that the provision of a sunshade or white paint colour could avoid/minimise the interference of ambient conditions in plant operation in cold and mild climates. However, they are not sufficient enough to mitigate against solar gain effect in warmer climates. Although reducing the maximum operating pressure would also help reduce the number of solar gain pressure events, it would also result in increased cushion level and hence reduced plant performance. The optimum design and operating strategy should be chosen for each individual station considering the daily and annual temperature profiles of the location.

Dissolved inorganic nitrogen and phosphorus dynamics in seawater following an artificial Saharan dust deposition event

The dynamics of dissolved inorganic nitrogen and phosphorus in seawater after a dust event were followed to better understand the impact of dust deposition in low nutrient waters of the Mediterranean Sea. Three independent abiotic experiments were performed over three seasons (winter, spring, end of summer) characterized by contrasted biogeochemical conditions. Experiments consisted of seeding evapocondensed Saharan dust at the surface of a polyethylene tank filled with filtered surface seawater. Phosphate (PO43-), nitrate (NO3-), size and number of particles and transparent exopolymeric particles production (TEP) were measured over the course of one week following seeding. Dust deposition was followed by a transient increase in [PO43-] during the first three hours with a maximum input of 33, 9 and 39 nM respectively in May, October and February. The removal of almost all the PO43- initially released suggests a scavenging process of PO43- back onto ferric oxide-rich particles leading to concentrations at the end of the experiment close to the initial values (7 nM in May and October, and 6 nM in February). NO3- released from dust was high especially in May and October (maximum input of 23 and 11 µM respectively) and was attributed to nitrogen dissolution from the large amount of small particles (< 1µm) rich in nitrogen in the evapocondensed dust. [NO3-] remained high until the end of the experiment (16 µM in May and 11 µM in October), indicating that NO3- from dust is likely to be bioavailable for a longer period compared to PO43- from dust. The release of PO43- and NO3- was intrinsically linked to particle dynamics, governed by the quality/quantity of dissolved organic matter.

Comments: New Fracturing Rules

Editor's column For US operators, new regulations from the federal government regarding hydraulic fracturing practices could not have come at a worse time. Already battling the economic fallout from sharply lower oil prices, the rules seem especially ill-timed for smaller operators that fear the requirements could have a long-lasting impact on how they do business. The new regulations proposed by the US Department of the Interior are designed especially to address public concerns about the safety of drinking water. The rules Require companies to disclose the chemicals they use in hydraulic fracturing operations. The chemical additives are to be listed on the FracFocus website, which many states already use for disclosure requirements. Set standards for the integrity of oil and gas wells, including using strong cement barriers between the wellbore and water zones. Elsewhere in this issue, hydraulic fracturing expert George King of Apache discusses well construction in a Beyond the Headlines column. Force companies that are operating on federal lands to store waste water in surface tanks instead of lined pits. Require pre- and post-drilling inspections and additional reporting requirements. The Interior Department estimates that the regulations will add approximately USD 45 million annually to operations costs on federal lands. But for oil and gas companies, the big concern is the precedent it could set for operations outside of federal lands, opening the door to additional regulation. The Independent Petroleum Association of America (IPAA) and the Western Energy Alliance, both trade associations representing oil and gas producers, have sued the federal government over the rules, claiming that they interfere with individual state’s rights to govern their land. Some states have also responded negatively, including Wyoming and North Dakota, indicating they may join the lawsuit. The interior secretary has said she hopes the rules will serve as guidelines for states desiring to regulate oil and gas activity. The lawsuit states the federal government standards were “a reaction to unsubstantiated concerns” and claims that “there is no factual, scientific, or engineering evidence necessary to sustain” the rules. “At a time when the oil and natural gas industry faces incredible cost uncertainties, these so-called baseline standards will threaten America’s economic upturn while further deterring energy development on federal lands,” said IPAA President and Chief Executive Officer Barry Russell. To the trade associations, the regulations represent a more aggressive stance on hydraulic fracturing from the federal government, which up to now has largely left that oversight to the states. Some local governments have banned outright or put limits on hydraulic fracturing. The Interior Department maintains that it tried to strike a balance among the concerns of the industry, those of environmentalists, many of whom would like to see further restrictions or an outright ban on fracturing, and the public. The new standards can be found on the Interior Department’s website at www.doi.gov. JPT

超声波对开水器内CaCO 3 结垢行为及其形态的影响

Contrast experiments on scaling effect using ultrasonic scaling method on the commercial water boilers are performed and the formed water scale is analyzed by SEM(scanning electron microscopy). Results show that ultrasonic can accelerate the formation of the scale microcrystal nucleus. The ultrasonic scaling method can promote the scale of the heating tube with high temperature on commercial water boilers, while it decreases the scale on the low temperature plate, such as water tank surface. Since the scale is mainly taken place on the heating tube, this method is not suitable for commercial boiler.

Leg weld fatigue cracks in anhydrous ammonia nurse tanks

In an accident in southwest Iowa, USA in 2012, an anhydrous ammonia nurse tank vented its entire cargo of 5500L (1500gallons) of liquid ammonia to the atmosphere. Follow-up study of the failed tank revealed a through-crack along a weld used to connect the tank to its running gear. Side-angle ultrasound examinations were performed on 532 used anhydrous ammonia nurse tanks to measure the locations, sizes, and orientations of flaw indications. The tanks examined had manufacture dates ranging from 1952 to 2011. A total of 83 indications were found in or near the leg welds of 50 of these 532 tanks. Several factors suggest that these indications are fatigue cracks, not the stress corrosion cracks more commonly detected in nurse tanks. These findings suggest that roughly 9% of the 200,000 nurse tanks in the U.S. nurse tank fleet may contain leg-weld fatigue cracks. Nurse tanks are the only large, pressurized packages for hazardous cargo that do not contain manways; thus, their interior walls cannot be inspected for flaws with magnetic particle or fluorescent dye penetrant methods. Since the tank interior is inaccessible, side-angle ultrasound is the only detection method capable of detecting cracks in nurse tanks initiating at both interior and exterior tank surfaces. For this reason, the authors recommend that side-angle ultrasound be considered for use in periodic nurse tank inspections.