Discharge Pipe Research Articles

Energy Losses Assessment of Smallholder Farmers’ Surface Water Irrigation Pumps in South and Southeast Asia Using Entropy Generation Principle

One of the most serious problems among smallholder farmers in South and Southeast Asia associated with the use of a surface water irrigation pump is low engine performance. The main cause of this low performance is the decrease in the flow field energy conversion mechanism caused by irreversible processes. The energy conversion theory suggests that pump efficiency is maximum when the loss is minimum. Whatever the origin of the losses, the deterioration in engine performance is due to a deterioration in the reversibility of the pump system. In this study, the pump is classified as the propeller impeller (PI), the improved axial or typical impeller (TI), and the conical hollow-shaped impeller (CI). Entropy production is applied to the pump on design improvement and loss sources location and mechanisms. The entropy production consists of viscous dissipation and turbulent dissipation. In this study, the pump design improvement of various designs based on entropy production has been studied in detail to predict energy loss in areas such as the inlet section, impeller, or discharge pipe. With the entropy generation, the optimum efficiency of different pump designs CI, PI, and TI were determined. The results showed that in all designs, more than 63% of the total entropy generation came from turbulent distribution. The flow in the pumps was analyzed in detail in comparison with entropy generation. It was found that the entropy generation rate increased in the secondary flow direction and was consistent with free-stream velocity. The PI design at the inlet pipe should be modified for reducing flow separation and entropy generation. All design impellers showed high energy losses, especially near the hub and tip along the leading edge and trailing edge. Therefore, it is possible to determine which features of the flow and entropy generation are relevant to the pump improvement.

Thermohydraulic Analysis of Ocean Thermal Energy Conversion

Thermohydraulic analysis is a mandatory analysis for power plants, including in this case marine thermal power plants (OTEC = ocens thermal energy conversion). The application to OTEC shows that temperature and pressure are things that must be considered, the higher the surface temperature, the greater the output power. Calculation of heat flow is a variable that is determined before a plant is built. This study aims to make a mathematical analysis of heat flow or thermohydraulic. The study uses the study of the heritage of Mendalan so that modeling and determination of design variables are formed, including heat flow in the pipe, diameter, hot and cold water discharge and boiler variables

Techno‐economic optimization of a hybrid system composed of pumped hydro storage, photovoltaic module, and diesel generator in a multi‐objective framework

AbstractHybridization of photovoltaic (PV) module (as a non‐dispatchable resource), diesel generator (as a dispatchable source), and pumped hydro storage (PHS) (as an energy storage) can provide a promising hybrid energy system (HES). The main outlook of the present study is to develop an efficient multi‐objective framework for optimal design of an off‐grid PV/diesel/PHS HES in which a wide range of parameters related to PHS system is optimized. In the optimization framework, nine decision variables (number of PV modules, number of diesel generators, reservoir installation height, reservoir depth, reservoir diameter, pump's rated power, turbine's rated power, charge pipe diameter, and discharge pipe diameter) are optimized with respect to two objective functions: total net present cost (TNPC) and loss of power supply probability (LPSP). To determine how TNPC is affected by the change of the input variables, a sensitivity analysis is conducted by varying capital cost of PV, PHS, and diesel generator. To obtain a well‐distributed and widely spread Pareto front, a multi‐objective chaotic crow search algorithm (MO‐CCSA) is introduced. Simulation results show that at LPSP = 0% and 5%, levelized cost of energy is around 0.59 and 0.55 $/kWh, respectively. Moreover, variation of the PV capital cost has a significant impact on the TNPC value.

Main problems in the operation of metal gas discharge pipes

This paper considers the main problems of operation of metal gas discharge pipes on the example of research and survey work on the examination of building structures of the exhaust tower with three gas discharge trunks 180 m high, flue gas purification unit of the sintering shop of LLP "NDFZ" in Zhambyl region. Analysis of the actual technical condition, considered in this article exhaust tower with three gas discharge shafts, according to the results of the survey, its volume-planning and structural solutions, showed its generally unrepairable, due to the mass of characteristic critical and unacceptable damage to the load-bearing elements of the frame, physical fatigue of materials, significant corrosion wear of metal structures, which will require a significant amount of proposed repair and maintenance work to eliminate them. The conducted complex of researches has shown that the service life of chimneys built before the 1960s and after has practically expired. Repair or reconstruction of chimneys using previously mastered technologies and materials does not solve the issues of reliability improvement. Rational solutions to these problems are periodic technical expertise by highly specialized organizations and implementation on its basis of methods of overhaul of both gas-exhausting trunks and building structures and interface units, wide implementation of which will solve the problem of extending the life of chimneys.

Simple criterion for evaluating stability of hydraulic oscillation based on water-hammer reflection coefficients

Hydraulic oscillation is a fluctuating phenomenon of pressure and discharge in pipes, which can threaten the safety of hydropower, pumping and water conveyance systems. To analyse the associated problems, new methods with simple form and clear physics are needed. This paper presents a water-hammer reflection coefficient-based criterion for stability evaluation of free-vibration of hydraulic systems. The stability (or attenuation) condition for a single pipe system is that the modulus of the product of the reflection coefficients at the inlet and outlet should be smaller than 1. For a complex pipe system, the condition necessary for stability is that every single pipe system is stable. To apply this new criterion to stabilizing the reservoir-single pipe-constant power turbine system by adding a head loss valve in the pipe, a formula for the critical head loss is proposed and verified. This new method is theoretically consistent with conventional methods, but more convenient in application.

Physical model of non-adiabatic blowdown of cryo-compressed hydrogen storage tanks

This paper describes a model of hydrogen blowdown dynamics for storage tanks needed for hydrogen safety engineering to accurately represent incident scenarios. Heat transfer through a tank and pipe walls affects the temperature and pressure transients inside the storage vessel and at the nozzle exit, and thus the characteristics of the resulting hydrogen jet in the case of loss of containment. Current non-adiabatic blowdown models are validated against experiments performed with hydrogen storage tanks at only ambient temperature. The effect of heat transfer for cryo-compressed hydrogen is more significant due to a larger difference of temperature between the stored hydrogen and the surrounding atmosphere, especially in case of equipment insulation failure during an incident. Our previous work demonstrated that the heat transfer through a discharge pipe wall can significantly affect the mass flow rate of cryogenic hydrogen releases. Thoroughly validated models of non-adiabatic blowdown dynamics for cryo-compressed hydrogen are missing at the moment. This work develops further the non-adiabatic blowdown model at ambient temperature using the under-expanded jet theory developed at Ulster University, to expand it to cryo-compressed hydrogen storage tanks. The non-ideal behaviour of cryo-compressed hydrogen due to low temperatures is taken into account through the high-accuracy Helmholtz energy formulations. The developed model includes effect of heat transfer at both the tank and the discharge pipe walls. The model is thoroughly validated against sixteen tests on blowdown of hydrogen storage tanks with initial pressure 0.6–20 MPa ab and temperature 80–310 K, through release nozzle of diameter in the range 0.5–4.0 mm, performed within the PRESLHY project. The model well reproduces the experimental pressure and temperature recordings in the storage tank during the entire blowdown duration for the whole set of sixteen tests. In conjunction with the volumetric source model, explained in detail, the physical model allows to perform CFD simulations accurately reproducing the temperature distribution in time and space for the cryogenic hydrogen jet experiment.

Обоснование списочного парка насосов и трубопроводных ставов рудничной водоотливной установки

The complex of drainage system of an underground mining enterprise ensures the safety and continuity of mining operations. Deterioration of the level of reliability of the functioning of the mine drainage system can lead to the following serious consequences. The main link of the mine drainage system is a drainage system equipped with pumping units based on the centrifugal pumps. One of the main criteria for the safe operation of a mine drainage system is its equipment with a sufficient number of pumping units. An assessment of the efficiency of the classical methodology for calculating the listed park of pumping units is given, including consideration of the amendment made to it regarding the given water inflow regime. The main drainage installation of the Udachny underground mine, equipped with sectional pumps, was chosen as the object of research. It is established that the list park of pumping units calculated according to the known methods does not allow to ensure a high level of reliability of the operation of the drainage plant. The same picture is typical for the park of discharge pipe sections of the drainage plant. When calculating the list park of pumping units of a drainage system, it is more expedient to consider not the passport performance of the pump, but its average value between major repairs. The number of pumps under repair depends on the average duration of repair work and the average time between failures of the pump. A method is proposed for calculating the optimal number of pumping units and pipe sections of a drainage system from the point of view of ensuring its reliable level of functioning. The results of the performed research will be useful to the specialists responsible for the design of drainage systems for underground mines and coal mines in the Russian Federation.

Heat transfer system design of sodium test facility STELLA-2

The STELLA program is arranged to support the development of PGSFR and as a part of this program STELLA-2 facility is under operation covering various significant transient experiments. The STELLA-2 facility is a large-scale sodium test facility capable of simulating the major transients of SFR, such as LOF, LOHS, TOP, Pump discharge pipe break, etc. The STELLA-2 facility is a down-scaled system of PGSFR including all the major components of the reactor. To minimize the distortion of scaling effect, the design process is very important, and engineering judgement is needed to realize the actual system. In this paper, the design process of the main heat transfer system of STELLA-2 is described and the similarity analysis results are also included. The experiment data in near future will be compared with the PGSFR safety analysis results. For further study, the distortion due to the down scaling needs to be addressed in more details with appropriate methodology.

Pilot scale continuous-flow solar water disinfection system by heating and ultraviolet radiation inactivating Acanthamoeba cysts and Bacillus spores

The consumption of biologically unsafe water and the resulting consequences persist especially in developing countries marked by resource-poor environments. Solar disinfection (SODIS) systems are the next step to upgrade SODIS for public drinking water supply on a community scale. In the present study, a continuous-flow system of solar water disinfection based on heating and ultraviolet (UV) radiation was developed and tested against Acanthamoeba castellanii cysts (1.38 ×103 cysts/L) and spores of Bacillus altitudinis 1.4 (1.8 ×104 CFU/mL). The system consists of a linear Fresnel solar collector (divided into infrared (IR) and UV radiation collector parts) coupled to a parabolic trough concentrator containing heat absorbers and quartz reactors fixed at its aperture and focus. Rotating wheels fixed at the base of the collector allow solar tracking in two axes. An apparatus composed of a secondary and heating tanks, as well as a retention and discharge pipe, allows the raw water to be heated until it overflows (at 92 ± 3ºC), flowing afterwards through the quartz reactors and being irradiated by UV (for 25 – 45 s). The system inactivated A. castellanii cysts (> 3 log/L) and B. altitudinis1.4 spores (2 log/mL), mainly due to the effect of heat. The daily productivity was 1200 L (flow rate of 3 ± 0.2 L/min, for 8 h). The system has the potential to be applied in the supply of safe drinking water on a community scale, with the cost of water being €0.0008 or €0.0004 per liter, using the version of the system with or without the UV part, respectively.

Failure analysis of slurry TBM discharge pipe in complex strata combined with wear and vibration characteristics

The slurry TBM circulation system plays a crucial role in supplying the slurry to the excavation face and conveying the cut rock particles to the ground. Rock particles in excavated materials will cause damage and failure of slurry discharge pipelines, which seriously restricts the efficiency of slurry TBM tunneling. In this paper, the two major behaviors of wear and vibration that induce slurry discharge pipelines failure are systematically investigated based on a water delivery tunnel located in Beijing. The wear morphology of typical pipes is studied combining the measured wear data and CFD-DEM coupling simulation. The time–frequency characteristics of slurry discharge pipe in different strata are measured and analyzed. Furthermore, the variation of time–frequency characteristics with the decrease of pipe wall thickness is investigated, a multi-parameters early warning methods based on vibration characteristics is proposed for detecting pipe wear. The results show that The CFD-DEM coupling method and Archard wear model can accurately determine the location of the maximum wear point of various pipes conducive to local thickening of pipes. The elbow pipe joints are prone to fatigue damage and have a high risk of slurry leakage during transport of large-sized particles. When the pipeline is severely worn, the interaction between the rock particles and the worn wall causes local elastic deformation, resulting in a high frequency response of 50–150 Hz and a rapid increase in the kurtosis K.

Fractional entropy-based modeling of suspended concentration distribution of type I and type II and sediment discharge in pipe and open-channel turbulent flows

Fractional entropy-based modeling of suspended concentration distribution of type I and type II and sediment discharge in pipe and open-channel turbulent flows

Strength evaluation of support frame of the low level liquid effluent pipes of nuclear plant

Disposal of low level radioactive liquid effluents of nuclear plant into the sea is carried out through carbon steel pipes inside a guard pipe. The treated effluents are discharged inside the sea beyond breaker zone through two disposal pipes. The disposal pipe discharges the treated effluent to two numbers of 1 m diameter pipe which goes down till sea bed. This guard pipe should be supported on top of the jetty against wind, wave, and dead loads. This study is intended to cover the design adequacy and material selection of the liquid discharge piping support configuration. Material and coating requirements of the support frame is chosen after careful evaluation of the prevailing saline environment and economic consideration. Elastomeric bearing provides necessary support & firm adherence of the support arrangement to the erected pile cap. Elastomeric bearing are easy to install and offer low maintenance. The support frame is checked for dead load, pipe load, live load, wind load, wave ¤t loads, and seismic loads. Wave and current loads were calculated based on Morison semi empirical equation. Linear elastic structural analysis of the support frame was carried out. This article provides insight to the materials used in supporting this pipelines and the basis behind the material selection. After material selection, strength evaluation of the structure is elaborately carried out for all the loads. Indian standards and API recommended practice were adopted for the strength assessment of the structure. Support arrangement is formed using trusses at different levels, spandrel girders and hangers connecting the spandrel girders. All the stresses for structural arrangement for liquid discharge pipe support are checked and found within acceptable limits.

Experimental and Numerical Research on Fluid Dynamic Interaction Effects of Reciprocating Pump–Pipeline System

AbstractThe performance of a reciprocating pump–pipeline system is often limited by the fluid dynamic interaction between pump, pipeline, and valves. In this paper, the fluid dynamic characteristics of a reciprocating pump–pipeline system are investigated via experiments and numerical analysis. A simple experimental platform consisting of a reciprocating pump, suction and discharge pipes, and flow control valve are offered and the experimental tests under multiworking conditions are carried out to explore the fluid dynamic interaction of the reciprocating pump–pipeline system. Combined with theoretical analysis and computational fluid dynamics (CFD) simulations, a dynamic model of the pump–pipeline system is presented with considering the fluid dynamic interaction effect of pump valves, plunger stroke, and flow control valve. All of the predicted results coincide well with the experimental data, and the inherent mechanism and the feature of the fluid dynamic interaction are revealed by experiments and numerical analysis. It is shown that the fluid dynamic characteristics of pipeline significantly influence the lag phenomenon and the motion behaviors of pump valves. The discharge flowrate rises nonlinearly with the increase of plunger stroke and the leakage rate is associated with the resistance of flow control valve. The pressure pulsation in discharge pipe is directly related to and markedly impacted by the control valve opening and the plunger stroke. However, the influence of the reservoir liquid-level on the system dynamic behavior is relatively slight. This work would give information for the optimum design and operation maintenance of reciprocating pump–pipeline system.

Flow stabilization and pulsation in external channels in fuel engines

A turbocharger installed in the gas exchange system of a reciprocating internal combustion engine has a significant impact on the gas-dynamic and thermophysical characteristics of the exhaust process. When installing a turbocharger in a discharge system, there is the possibility of mitigating local pulsations of flow rate and pressure in the discharge pipe. The use of such an exhaust system increases the output capacity of the piston fuel engines outlet pipeline by approximately 20%, which also has a positive effect on the performance of individual systems and units such as the turbocompressor and exhaust manifold and reduces the temperature stress of the engine exhaust system and turbocompressor turbine elements.

Development of a vortex wind device

The relevance of the research is related to the development of a new type of renewable energy source ‒ a vortex wind device with a vertical axis of rotation without wind guidance mechanisms. The main purpose of the study is to develop a vortex wind turbine using mathematical modeling of vortex motion and laboratory experiments on the model. The object of the study is a vortex wind device consisting of a concentrator with curved channels, inside which there is a wind wheel, and a vertical pipe mounted on the concentrator. The calculations are based on the method of modeling large vortices with the solution of averaged Navier-Stokes equations. As a result of the research, the velocity distribution in the concentrator, inside the structure and the discharge pipe were obtained. The computational experiment shows that the narrowing channels of the concentrator create a stable vortex motion inside the structure and the vertical pipe. The methods used for calculating turbulent flows allow to study aerodynamic processes in wind turbines with a vortex effect. The absence of a rotary mechanism reduces the risks of breakdowns of rotational elements due to their absence. The concentrator perceives the wind flow from any side and creates a vortex motion inside itself due to curved channels. The outlet openings of the curved channels are directed to the blades of the wind wheel, which increases the maximum transfer of wind flow energy to the blades of the wind wheel. The vortex motion inside the concentrator creates a steady rotation of the wind wheel. An additional important point is the removal of the exhaust air flow from the vortex wind device. Existing wind farms have wind guidance mechanisms, which complicates the design, a stable rotation mode of the wind wheel is not created. All these problems of operating stations can be solved with the help of a vortex wind device

Interactions among science, environmental policy and public perception in a Mississippi River Delta assimilation wetland

In November 2006, the City of Hammond, Louisiana, began discharging secondarily treated, disinfected municipal effluent through a distribution pipeline to a 14,000 ha emergent wetland complex referred to as the East Joyce Wetlands. The primary goals were to improve local water quality by taking effluent that would normally be discharged to local waterways and directing it to wetlands that were hydrologically isolated and degraded by saltwater intrusion. During the 2007 growing season there was robust growth of marsh vegetation with a near doubling of productivity compared to controls, however, during winter 2007 there was a massive decline in vegetation and transition to open water in the 121 ha of wetlands in the direct path of effluent discharge. Herbivory by nutria was found to be the cause of the decline, but not before several other causes were hypothesized and largely accepted by the public, specifically that the cause of the vegetation decline was due to excess nutrients that increased rates of soil decomposition and limited root growth of plants. Studies show these hypotheses were flawed due to scale and methodology issues. Intensive nutria removal began in the spring of 2008 and continued through the winter of 2008–2009, with approximately 2000 nutria killed, and vegetation recovery began during the spring of 2009, which was most pronounced and consistent nearest the discharge pipe. Vegetative cover increased dramatically from the near complete loss after nutria grazing to near 80% by 2015, and wetland recovery has continued to the present.

Development of flow-vibroacoustic coupled numerical methods for prediction of noise radiation due to flow-born vibration of compressor discharge piping system

The compressor and fan in air conditioner outdoor unit are the core component which deter-mines noise performance as well as cooling or heating performance. Among these, the com-pressor has larger contribution to the noise of outdoor units. For high efficiency air condition-er, the size and operating speed of compressor are smaller and faster. The high-speed com-pressor causes loud noise which is complaints for the customer. Traditionally, it is well-known that the vibration of compressor and connected duct is main noise source. However, as the compressor speed increases, the refrigerant flow in the compressor discharge duct also emerged as a major noise source. To reduce the compressor noise operating at high speed, it is necessary to analyze vibrational and acoustic characteristics of compressor discharge duct. This duct noise has the two-types source: structure born noise and flow induced noise. The structure born noise is generated by the duct vibration caused by compressor movement. For the flow induced noise, the static pressure field of refrigerant flow in the duct is vibrational source. In this paper, the compressor discharge duct noise considering two mechanisms was investigated. The refrigerant flow is solved using CFD and duct vibration and noise radiation are computed by FE-BE method.

Experimental and theoretical study on work conversion and heat transfer of R290 linear compressor

To analyze the work conversion and heat transfer performance of the linear compressor, this study established a steady-state thermodynamic analysis model of a low-back-pressure linear compressor based on a variable capacity performance test. The influence of the heat transfer of the compressor components inside the shell on the cooling performance was analyzed. By improving the insulation of the inner discharge pipe, the cooling COP increases from 3.81 to 4.24. Through the experimental analysis of the linear compressor with cooling capacity adjustment, the quantitative results of the work conversion and heat transfer are obtained. The most proportion of the reheating capacity is transferred to the suction gas. Meanwhile, the heat transferred from the discharge pipe accounts for the most proportion of the total reheating capacity, which is about 62.8% – 86.2%. The larger the cooling capacity is, the smaller the proportion is. It presents a polynomial relationship of the fourth power by curve fitting between the direct suction ratio and the cooling capacity ratio. The thermodynamic parameters of the suction mixing region show that the direct suction ratio just ranges from 42% to 65%, resulting in about 14.0 °C ∼21.9 °C temperature increase from the suction heat transfer. To improve the compressor efficiency, it is effective to reduce the mix region by optimizing the suction passage inside of the compressor shell as well as reduce the heat transfer from the discharge pipe.

RESPONSE OF A FIRST-ORDER SERIES SYSTEM TO THE TRANSFER FUNCTION, THE LIQUID LEVEL OF TWO INTERACTING TANKS

This article presents the experimental and theoretical results of the discharge and filling of water between two torispherical tanks connected in series at different heights, the model that was used was developed with equations reported in the literature for geometries of torispherical tanks and it was necessary to develop two more equations in the laboratory to calculate the discharge and fill volumetric flows for the tanks used. The unloading and filling model was obtained with transitory mass balances resulting in two simultaneous linear differential equations where the unloading and filling heights are related as a function of the operation time. The model was solved numerically, and the experimental results were compared against those of the proposed model, finally the transfer function for this system of interacting tanks was found. KEYWORDS: Transient mass balances in two atmospheric interacting tanks at different heights and equal torispherical geometries. The discharge and fill model of two interacting tanks as a function of time. The volumes of partially filled torispherical tanks. The transfer function of a pulse in the discharge pipe that affects the volumetric flow within the discharge tank.

Study of the inertial separator of the clover thresher with a pneumatic loader

The clover thresher with a pneumatic loader, having an inertial louvered counterflow separator, is characterized by a simple design and operation, reliability and durability, convenient arrangement with other elements of the pneumosystem and relatively low hydraulic resistance. The wedge-shaped sedimentation chamber (separator) with a horizontally displaced discharge opening towards the inlet window is equipped with a louvered partition installed at the junction of the inlet and outlet windows. To determine the basic design parameters of the inertial louvered counterflow separator of the clover thresher, the authors experimentally studied the hull of meadow clover with a humidity of 12 to 14% of the following composition: 57.4% of beans with seeds; 16.6% of free seeds; 25.0% of light impurities; 1.0% of heavy impurities. As a result, the main design parameters of the separator have been determined: the length of the louver grille is 210 mm, the pitch, length, angle of installation of the louver plates are 40mm, 50 mm, 30°, respectively, the height of the inlet and outlet windows of the separator is 120 and 280 mm, the height of the outlet windows of the louver and counterflow cleaners is 190 and 80 mm, the depth of the discharge pipe of the sedimentary chamber is 570 mm. The efficiency of the pneumatic loader when feeding 300 kg/h: the amount of released heavy impurities - 100%, light impurities -33.6%, loss of full-fledged seeds to waste - 0.8% hydraulic resistance - 196 Pa. The research results give grounds to recommend this design for application.