Branch Pipe Research Articles

Reasons analysis of the large deviation in the NOx emission data of the coal-fired power plant

The problem of the large deviation in the CEMS (Continuous Emission Monitoring System) data of NOx emission from the coal-fired power plant is analyzed. The deviation existed between the data measured at the chimney and the outlet of the denitration system. On-site inspection and testing are carried out. The results show that the uneven distribution of NOx concentration at the denitration outlet caused by the uneven ammonia injection, is the main reason for the difference in the NOx concentration monitoring value between the chimney inlet and the outlet of the denitration system. Several suggestions are given to reduce the deviation between the CEMS monitoring data and the actual average data. In the subsequent operation of the denitration device, AIG ammonia injection optimization and adjustment tests should be carried out regularly. The ammonia injection branch pipes and nozzles should be checked, especially at the shutdown time.

Estimation of pipeline systems flexible connecting pipe strength properties based on numerical study of strain-stress state

Vibration-isolating structures on rubber-cord casings are used in pipeline systems which are of great importance for the transportation of hydrocarbons. Implementation of a compensating pipe eliminates the load transfer from the pressure of the working medium to the structural elements of the pipeline. A three-dimensional model based on a numerical study and reinforced with beam elements is used to estimate the strength properties of a rubber-cord branch. The calculation of the stress-strain state of the rubber-cord casing and the flange connection of the branch pipe has been carried out. The results are to be considered when designing and operating pipe structures based on reinforced casings.

Investigation of weld cracking of a BOG booster pipeline in an LNG receiving station

The weld cracking failure of a boil of gas (BOG) booster pipeline in a liquefied natural gas (LNG) receiving station was investigated through macroscopic observation, physical and chemical inspection, optical microscope, scanning electron microscopy (SEM) and energy dispersive spectrometry techniques (EDS). The finite simulation analysis (FEA) method was used to examine the effect of compressor vibrations on the welding. The results showed that the crack originated from the outer surface of the butt weld between the main and supporting branch pipes. Due to the poor machining dimensional accuracy of the welding fit, three pass welding with a large amount of metal filling was processed to connect the weld. The microstructure analysis results of the weld indicated that several solidification cracks were generated between the welding passes. Moreover, many inclusions and harmful super-sized second phases were generated in the weld, with several microcracks occurred around these inclusions and second phases. The finite element analysis (FEA) calculation results showed that the vibration of the compressor did not directly lead to weld cracking, however, under the influence of the vibration, the multi-source solidification cracks and microcracks originated from the surface of the butt weld, and propagated through the whole weld, which were lead to the cracking failure. Several suggestions to prevent such a failure were proposed to avoid the occurrence of similar accidents.

Temperature and pressure oscillations induced by steam direct contact condensation in a T-junction with porous inner-structures

Steam direct contact condensation (SDCC) has been investigated experimentally with the steam mass flow rate in the range of 2 ~ 60 kg/h, the subcooled water flow rate in the field of 0.5 ~ 2 m3/h and the subcooled water temperature at 30 °C.in an empty T-junction and the T-junction with two porous inner-structures (made up by stainless steel ball with two different diameters). The effects of different porous inner-structures on temperature and pressure oscillations were investigated with different saturated steam mass flow rate and subcooled water flow rate. The results show that the porous inner-structures significantly reduces the temperature fluctuation near the branch pipe. Then, the positive peak value of pressure oscillation increases firstly and then decreases with the increase of porous inner-structures porosity. the intensity (RMS) of pressure oscillations were suppressed by filling the porous inner-structures. Besides, filling the porous inner-structures increases the viscous resistance and inertia resistance of the flow and enhances the intensity of turbulence. So the first dominant frequency increased significantly as the porosity of porous inner-structures decreased. Especially when the porosity ε = 0.318, the increase of the first dominant frequency is particularly evident and the maximum even reached 463 Hz.

Layered application of mineral fertilizers with the coulter ripper of a combined unit

The applied methods of fertilizing cotton in Uzbekistan have a number of significant disadvantages. They do not provide available nutrients to the plant’s root system. With the distribution of fertilizers in the zone of root development in layers in the required ratio, the coefficient of their use and the yield of cotton increases. (Purpose of the study) To substantiate the design parameters of a subsoiler’s distribution pipeline for three-tier fertilization. (Materials and methods) The design of a developed pipeline distributor for three-tiered fertilization is presented. The subsoiler is equipped with a fertilizer distribution pipe, which consists of a cylindrical and inclined funnel-shaped part, a high-flow channel and a lower fertilizer distributor. In the conductive channel, two branch pipes with reflective plates are installed, which cut the moving fertilizers and direct them to the appropriate soil horizon. (Results and discussion) We investigated the movement of mineral fertilizer granules along the fertilizer channel, on the basis of which the length of the pipes of the upper and middle tiers was determined.Experiments were carried out to study the influence of the length of the protruding part of the baffle plates of the branch pipe and the angle of inclination of the pipeline-distributor funnel on the distribution of fertilizers and on the unevenness of the flow of fertilizers into the upper, middle and lower tiers. The parameters of the loading funnel of the vertical pipeline, branch pipes and movable plates of the upper and middle tiers, in addition to the fertilizer diffuser of the lower tier, were substantiated.We theoretically and experimentallysubstantiated the parameters of the nozzles of the upper and lower tiers. With optimal lengths of the branch pipe and baffle plates, a given fertilizer placement depth is provided in three tiers with the required amount of fertilizer. The influence of the parameters of the distribution pipeline on the uniformity of fertilizer distribution in the upper, middle and lower tiers was established. The rational parameters of the lower fertilizer spreader were substantiated, which ensures uniform distribution of fertilizers over the working width of the working body.

Thermal Fatigue Assessment for Penetration Flow into a Branch Pipe of Mixing Tee

Thermal Fatigue Assessment for Penetration Flow into a Branch Pipe of Mixing Tee

A Review of Main Factors Leading to Air Pressure Fluctuations in Branch Drainage Pipes inside Buildings

This paper is to discuss the main factors leading to the air pressure fluctuations in appliance branch pipes and measures to control them. It has been established that the main factors characteristics of a good sanitary pipework system are that it must prevent the transmission of foul air into the building, minimize blockages, provide efficient conveyance of discharge from sanitary appliances and minimize the risk of flooding to any part of a building. However, due to the nature and properties of sanitary appliance discharge, the flow being a three-phase flow which is simplified to two-phase for design computations and discharge being probabilistic, air variations in the horizontal appliance pipe result in phenomenon in which the sanitary network fails to perform as designed and installed to prevent or minimize aforementioned circumstances. It has been established that the main factors to be discussed leading to air pressure fluctuations in the appliance branch pipe are water traps, bend structures, pipe diameter, pipe slope and length, angle and connection mode and ventilation conditions. These factors’ associated control measures have also been presented. However, factors pertaining to concentration of appliance discharge have not been discussed. The result of this discussion will enable designers and installers of sanitary pipework to incorporate measures to control air pressure fluctuations in appliance branch pipes inside buildings.

Influence of Bifurcation Pipe Position on Hydraulic Turbulence for Pumped Storage Power Station

There must be hydraulic turbulence transient in the pumped storage power station with one pipe corresponding to several units. This paper established a simulation model by using the method of characteristics for a pumped storage power station to analyse how the change of upstream and downstream bifurcation pipe position and different arrangements of downstream surge tank affect the hydraulic turbulence. The results indicate that unit output’s amplitude of power mode is smaller than that of frequency mode. And the upstream and downstream bifurcated pipes far away from the units can reduce the hydraulic turbulence of normal operating unit while the upstream without bifurcation pipe is better than the downstream without bifurcation pipe to control the output swing. Sharing the downstream surge tank can effectively reduce the maximum relative over output of the unit, while the surge tank placed in the downstream branch pipe will worsen turbulence process.

Thermal Fatigue Assessment for Penetration Flow into a Branch Pipe of Mixing Tee

Thermal Fatigue Assessment for Penetration Flow into a Branch Pipe of Mixing Tee

ВЛИЯНИЕ ТУРБУЛЕНТНЫХ ПУЛЬСАЦИЙ НА ПРОЦЕСС ФРАКЦИОННОГО РАЗДЕЛЕНИЯ МЕЛКОДИСПЕРСНЫХ ПОРОШКОВ НИТРИДОВ МЕТАЛЛОВ

This paper presents a numerical study of a two-phase swirling turbulent flow in a separation element of a vortex chamber. The paper considers a process of fractional separation in the separation chamber with three particular features in its design. The main feature is the separation mobile element located at the outlet of the separation area. Changes in the position of this element can affect the boundary size and the sharpness of the separation. The second feature of the considered separation chamber is the presence of a rotating element along the vertical axis. This element helps to align the field of the circumferential velocity component. The third feature of this chamber is the presence of a branch pipe for the auxiliary gas flow supply intended to push the particles away from the chamber wall and to blow the separated particles in order to prevent them from agglomeration. In this work, the trajectories of the motion of fine nitride particles are calculated taking into account the turbulent diffusion effect. A possibility to control the boundary size of the particles, when moving the separation element located at the outlet of the vortex chamber, is demonstrated. Numerical study results show that the turbulent pulsations cause significant changes in the separation process and affect the boundary size and the sharpness of the separation.

Vertical U-shaped heat exchangers for construction engineering: New promises and future challenges

The ground source heat pump system is a promising technology for building heating and cooling by using underground energy, however, many technical problems, e. g. low energy utilization rate and inefficiency operation, have greatly hindered its wide applications. This paper studies the key technologies of vertical U-shaped heat exchangers in construction engineering to solve the bottleneck problem and optimizes the system. Three commonly used backfill methods are analyzed, and a double U-shaped branch pipe is recommended to improve construction efficiency. The paper sheds a bright light on green energy utilization with high-efficiency, energy-saving, and environmental protection.

Влияние осадка остаточных топлив на напряженно-деформированное состояние вертикального стального резервуара

The article studies the formation of the total sediment by the incompatibility of residual fuels and oil products, analyzes and calculates the stress-strain state of the tank taking into account oil products and sediment. The studies examined the influence of temperature fields on the sedimentation of a mixture of residual fuels caused by the incompatibility of these components. Temperatures of a stored product, namely residual fuel RMK-700, and ambient temperatures are taken into account when modelling in ANSYS product. Effects that oil product has separately and oil product with bottom sediments have on a stress-stain state are compared. Laboratory tests were performed to accurately measure density depending on various temperatures. By means of finite element method a stress-stain state of a vertical steel tank RVS-20000 is examined, the calculations showed that the maximum stresses are located in zones of the weld seam and in the places of installation of the receiving-distributing branch pipe and manhole. In these areas bottom sediment and temperature difference influence the stress-stain state greatly, with the stresses becoming even higher as the wall gets thinner.

TECHNOLOGICAL APPROACHES FOR SANITARY PROCESSING OF FOOTWEAR AND CLOTHES OF LIVESTOCK WORKERS

Effective control of the quality and safety of livestock products is possible only with the implementation of a scientifically grounded complex of veterinary and sanitary and general economic measures. The goal of our work was to develop effective ways to sanitize clothing and footwear of workers in the livestock industry. The studies were carried out following the current methodological approaches that are used in agriculture and veterinary medicine. Based on the results of the research carried out, two methods and one device have been developed to ensure a high level of veterinary and sanitary measures in animal husbandry. It has been proven that for the sanitization of clothing of workers in the animal husbandry industry, it is effective to use a disinfectant, which includes the sodium salt of dichloroisocyanuric acid (0.09–0.36%), adipic acid (0.01–0.04%), sodium bicarbonate (0.01–0.04%), sodium carbonate (0.003–0.01%), water (99.887–99.55%) when exposed for 30 minutes. For disinfection of workers' footwear, it is advisable to use disinfectants filled with a disinfectant that contains dichlorantin (0.021–0.21%), 5,5-dimethylhydantoin (0.0164–0.164%), a dispersant (0.012–0.12%), anionic surfactants (0.005–0.05%), corrosion inhibitor (0.01–0.1%), filler (0.0356–0.356%) and water (99.9–99.0%). An innovative device for cleaning and disinfection is proposed - a shoe disinfector, which consists of a waterproof box with a bottom wider than the top, filled with a disinfectant solution, a branch pipe for removing waste solution, a brush shaft, which is fixed in the upper part of the waterproof box, an electric motor with a rotational speed 2 rev/s., Which serves as a drive shaft brush, control panel with a start button and a stop button. The proposed developments complement the existing regulations on veterinary and sanitary measures at livestock farms and complexes.

УСТАНОВКА ДЛЯ ФИЗИЧЕСКОГО МОДЕЛИРОВАНИЯ ПРОМЫВКИ ЗАСОЛЕННЫХ ПОЧВ

Gradients of salts concentrations of the soil solution, rinsing water pressures, filtration coefficients determine the flow intensity of the salt solutions in the aeration zone. There are known a lot of software for calculating the motion of salt solutions in the porous medium. To assess the accuracy of calculations of the salts movement in the soil, the data of gradient measurements are used. The implementation of the known methods of physical modeling on the soil monoliths mounted according to Astapov, lysimetric installations, in experimental leaching of saline soils in the field requires significant material investments, labor and time. Minimum material and labor costs are required for the assembly and use of the proposed design of the installation for physical modeling of saline soil washing. A working prototype of the installation has been developed. It includes piezometers, a case, units of piezometers connection, sampling of soil moisture combined with soil electrodes, equalizing drain, rotating part of the case. Piezometers, drains and connecting hoses, soil moisture sampling unit. The installation case is assembled of separate branch pipes equipped with necks and sealing rings. Filtration investigations and gradient measurements of the salts movement are carried out on the installation. The tests of the installation prototype were fulfilled in the field on the sand pit reclamation map located in the floodplain of the Gzhelka and Moskva rivers of the Ramensk region of the Moscow area. The profile filtration coefficients measured at the installation – 2.33 ± 0.031 m / day and in the field conditions – 2.36 ± 0.041 m / day do not differ significantly.

Experimental and CFD Investigation into Using Inverted U-Tube for Gas Entrainment

An experimental and numerical study is presented in the current work for gas entrainment using an inverted vertical U-tube. Water flows vertically up in an inverted U-tube which creates a low-pressure region in the tube upper portion. This low-pressure region can be used to extract gases by connecting it to a branch pipe. The extracted gases considered in this work are a mixture of air and water vapor. The water vapor from the side branch pipe is mixed with the flowing water under the siphon effect. This results in a progressive water vapor condensation as the mixture proceeds towards the exit due to an increase in vapor partial pressure. The air is drawn by inertia to be released out at the tube lower exit of the inverted U-pipe. The current study deals with these complicated flow behaviors due to the mixing undergoing condensation. A test rig is designed for experimentally studying the behavior of water flow in an inverted U-tube where the air is mixed with the flowing water at the top region of this tube. The CFD computations are accomplished for a side gas mixture with volume fractions up to 0.7 with water vapor mass fractions in this mixture to be 0.1–0.5. The tested water mass flow rates in the main tube are 2, 4, 6, 8 kg/s to account for all possible flow mass ratios. The CFD computations are validated with water and air two phase flow with the measurements of both the experiments of the current research and the literature. The present results reveal that slightly raising the water mass flow rate at a constant side mixture mass ratio produces a reduced generated pressure in the upper tube part. This is attributed to extra water vapor condensation taking place rapidly by increasing the water flow rate in the tube upper part. Furthermore, the turbulence quantities begin to break down at a side mixture volume fraction of 0.55 with water and air mass flow rates of 2 kg/s and 0.002 kg/s, respectively. On the other side, raising the air mass flow rate at the higher values of water vapor and water mass flow rates breaks the generated vacuum pressure and turbulence due to entrainment. Moreover, this proposed framework can produce a lower static pressure, reaching 55.1 kPa, which makes it attractive for gas extraction. This new technique presents innovative usage with less consumable energy for extracting gases in engineering equipment.

Experimental investigation on gas‐liquid flow distribution in downward parallel pipes of a 660 MW ultrasupercritical CFB boiler

SummaryThe arrangement of downward flowing evaporation heating surface in the furnace can effectively reduce the height of the furnace in the ultrasupercritical circulating fluidized bed boiler. According to the structural parameters of 660 MW ultrasupercritical circulating fluidized bed boiler, the scaled experimental system was established on the basis of the similarity criterion. The distribution of the gas–liquid two‐phase flow in the parallel branch pipes of the downward and the upward water‐cooled wing‐wall was studied under the rated loads of 25%, 50%, and 70% THA. The void fraction distribution, flow distribution of each phase, and dryness distribution in each branch pipe of the downcomers and the risers of the water‐cooled wing‐wall were measured via the quick‐closing valve method and the split‐phase measurement method. In the downward water‐cooled wing‐wall, both the nonuniform coefficient of void fraction and dryness in each branch pipe decreased with the increase in dryness in the inlet header. Under the same average dryness, the nonuniform coefficient of the void fraction increased with the increase in load. In the upward water‐cooled wing‐wall, under the same load, the uniformity of flow distribution was improved as the dryness increases. Under the same dryness condition, as the boiler load increases, the deviation coefficient of each phase distribution between the parallel pipes increased and the unevenness increased. In the study of flow and heat transfer characteristics of two‐phase flow, the void fraction α is a very important intermediate calculation parameter. The correlation formula of the cross‐sectional void fraction in the downward water‐cooled wing‐wall was fitted, and the calculation result was better compared with drift‐flux model, with an error of −6% to 6%.

Analisa Head Loss Akibat Percabangan Pada Sambungan Reducing T Dengan Variasi Diameter Penampang

Head loss is a phenomenon of flow losses in the piping system. Head loss is very detrimental in fluid flow, because it can reduce the efficiency of fluid flow. This study aims to determine how much the value of head losses (hT) is that occurs in the reducing T pipe connection with diameter variations on the pipe branch 0.0254m (1 inch), 0.019m (3/4 inch), 0.0127m (1/2 inch). This research was carried out experimentally by measuring the branching flow of the flowing fluid by recording the time and volume of water that had entered the measuring tank, then reading the preasure on the manometer. The results showed that the increase in flow rate (Q) was directly proportional to the head loss (hT). Flow greatly affects the size of the Reynolds number of the three connections, the lowest total head loss occurred in the 1-inch reducing T pipe connection with a value between 0.1715 m- 0.2814 m and the highest total head loss occurred in the reducing T inch pipe connection with a value between 0.4110 m- 0.5867 m.Keyword: Reynold Numbe, debit, head Loss

Acoustic connection between thermoacoustic engine and impulse turbine

In this study, we studied how to connect a thermoacoustic engine (TAE) and an impulse turbine to construct a thermoacoustic generator for converting thermal energy into electric power. The thermoacoustic generator was separated into two sub-systems: (1) system A, which consisted of a looped-tube TAE and a branch tube, and (2) system B, which consisted of an impulse turbine loop and a branch tube. The sub-systems were evaluated individually using an acoustic driver to determine the driving conditions such as branch length, driving frequency, and temperature for the connected system. In system A, which included the TAE, the change in specific acoustic impedance was small with respect to the velocity amplitude. However, in system B, which included the impulse turbine, the change in specific acoustic impedance with respect to the velocity amplitude was nonlinear. The sub-systems were connected by branch pipes, whose lengths were determined from the individual sub-system evaluation results, and the device was confirmed to self-oscillate at the driving temperature. When the device was operated at the driving conditions, the frequency, velocity amplitude, and specific acoustic impedance with self-oscillation were the same as those of the individual sub-systems. This also confirms the validity of evaluating the TAE and impulse turbine separately.

Анализ причин разрушения деталей трассового изготовления

About 4 % of the connecting pieces used in the construction of oil pipelines in the 1950s–1970s were manufactured in the field. Despite the fact that in recent years the number of such parts has significantly reduced, failures associated with their lack of reliability occupy a noticeable share in the total number of failures in the system of oil trunk pipelines. The purpose of this work is to analyze the typical causes of failure of connecting parts using the example of a tee bend with a reinforcing plate. The authors carried out structural and fractographic studies of the defective structure. On the basis of information about the operating conditions and the actual characteristics of the bend metal, as well as data on the centers of destruction and the nature of crack propagation, computer modeling of the stress-strain state of the part was carried out. Based on the results of metallurgical studies and computer modeling, it was established that the cause of the formation of a through crack in the weld at the junction of the main oil pipeline and the reserve branch was excess stresses in the area of welding of the reinforcing plate to the branch, exceeding the tensile strength of the material of the tee branch pipe.

Electromagnetic-conductance measurement method for the flow rate and void fraction of gas-liquid two-phase flows

Gas-liquid two-phase flow systems are widely existed in many engineering systems and industrial processes, and measurement techniques for two-phase flows are crucial in a diverse range of engineering applications. Most of the existing measurement techniques usually brought extra resistance to the flow in the branch pipes and, to some extent, influenced the original distribution of the gas-liquid two-phase flows in the parallel T-junction system. In order to study the distribution characteristics of two-phase flow in vertically parallel T-junctions, the electromagnetic-conductance measurement method was developed to measure the void fraction and liquid flow rate of the gas-liquid two-phase flow in the branch pipes. Electromagnetic-conductance measurement technique has the advantages of high response rate, satisfactory accuracy and low disturbance on the flow field of gas-liquid two-phase flows. In order to calibrate the conductance measurement method, experiments were carried out with the liquid velocity range of 0.2–2 ​m·s-1, the gas velocity range of 0–50 ​m·s-1 and the volume void fraction range of 0–0.99. Through the calibration experiments, the relationship between the resistance value of each conductivity sensor and the volume void fraction of two-phase fluid was decided to be established as a logistic function. By the error analysis of the calibration results, 75.9% of experimental results of the void fraction in the gas-liquid two-phase flow fell within the ±20% error bands. The electromagnetic-conductance measurement method proposed in this paper could provide a reference for accurate and non-interference measurement of two-phase flow in parallel T-junctions.