Simple Pipe Research Articles

Study on Energy Converter from Waste Heat of Automobile Engine

Utilization of alternative fuels and utilization of waste heat has also become a major research area. This study reports on an investigation on a development of an energy converter of heat engine that converts energy from a waste heat flow process into acoustic power. The energy power converter operates with a temperature gradient imposed on a Celcor ceramic stack which then induces pressure oscillations. The system consists of a simple stainless steel pipe tube with a range of diameter open at one end. A waste heat gas is used to model a potential heat source from automobile engine. A two heat exchanger is required while copper plates are used as the ambient heat exchanger and hot heat exchanger. Effects on pressure oscillations have been observed with a calculated heat rate of 50 W at the stack. The system which operates at atmospheric pressure with air as the working fluid indicates a potential in utilizing the heat produced from waste heat automobile engine into making a new energy resource.

AN OVERVIEW OF STRESS ANALYSIS OF HIGH-ENERGY PIPELINE SYSTEMS USED IN THERMAL POWER PLANTS

A typical high-energy piping systems consists of the main steam, reheat (hot and cold) and boiler feed pump (BFP). The initial design of the system is based on elastic analysis to ensure that the stresses and deflections fall within established code limits. The important reason for analyzing the piping is that many power plants were built before (40 to 50 years) computer analysis techniques were available. The main aim of piping stress analysis is to check the design, which will allow simple and economical piping supports and provide flexibility to the piping system for thermal expansion. The piping stress analysis is carried out using CAEPIPE software. By using this software we can evaluate stresses, stress ratios, flange condition, support loads, element forces and displacements at each node. In this paper, only the maximum and minimum displacement results are tabulated.

The Stability of a Pipe Stand Racked in a Derrick, Part 1—Foundation

Summary The paper presents an exact analytical solution using higher-order functions for the deflection and buckling of a simple pipe stand in a derrick, modeled as an inclined slender column, with self-weight and pinned at both ends. The results are consistent with industry practice where an intermediate finger board is used to support 93-ft stands of both 2⅜- and 2⅞-in. steel pipe but is not required for 3½-in. pipe. These observations suggest a suitable safety factor for application in other cases. The results are an important limiting case for the general pipe-stand model presented in Part 2. Buckling lengths are presented for a range of pipe sizes and types. Sensitivities, such as the presence of tool joints, differences in material, wear, and the effect of pipe stick-up above the top racking board, are also introduced. Although there is good agreement between the theory and operational practice for triples, further investigation is needed for quads. Construction columns are normally designed to support significant loads, and in most cases, self-weight plays only a minor role. This is not the case for a simple pipe stand in a derrick, for which stability is solely dependent on self-weight. More-formal analysis of these conditions is warranted because of the trend of increased mechanization and the need to preserve safety and improve operational efficiency. To the author's knowledge, there is no existing industry guidance for the flexing and stability of pipe stands in a derrick.

Maximum air entrainment into a mixing pipe through optimum design

Numerical simulation of air entrainment into a mixing pipe has been performed by solving the equations of conservation of mass, momentum and energy along with a two-equation-based k–ϵ model. It was found that there exists an optimum shape of the mixing pipe (both for non-isothermal and isothermal flow condition) for maximum air entrainment into the pipe. It was also found from the numerical experiments that there exists an optimum length of the mixing pipe, both in forward and reverse direction, with respect to the position of the exit of the nozzle that can entrain maximum air into the pipe. There also exists optimum diameter of the mixing pipe and optimum distance of the nozzle from the entrance of the mixing pipe (irrespective of the different Reynolds number based on nozzle) that entrains maximum air into the pipe. For same Reynolds number, the cylindrical mixing pipe has interestingly a much shorter entrance length compared to a simple pipe. An optimum nozzle diameter could be decided by considering the mixing pipe entrainment rate and the back pressure developed by the nozzle.

Cooling of a photovoltaic module with temperature controlled solar collector

The efficiency of photovoltaic modules decreases with heating, so there has been an increase with regard to the solution of the problem. Photovoltaic module converts the incoming solar radiation into heat and electric energy. Due to this heating feature of photovoltaic modules, it is likely to produce heat energy from PV modules as well. Such systems are called as both a photovoltaic and thermal systems in the literature. A lot of experimental studies were done by special processing on the PV module. Since the studies require special processing on the module, they remain as laboratory work only. In this study, different PV/T systems were experimentally analyzed for the cooling photovoltaic modules. A simple pipe was placed on PV module as a spiral heat exchanger in order to provide active cooling. Also, the system can easily be applied to large-scale systems. As a result of experimental research, the module efficiencies with cooling were calculated as 13%, and the module efficiencies without cooling were about 10%. As the set temperature increased, module temperature can be increased or decreased. The module temperature was changed according to solar radiation and set temperature. As the solar radiation increased the module temperature decreased in this experimental system. The solar radiation has nothing to do with set temperature for this system.

Developing a monitoring system for long-distance pipeline leakage incorporating fusion of conflicting evidences

Quite often, during long-distance pipe leakage, critical decisions have to be made quickly and with as much certainty as possible using conflicting and uncertain sources of information. Key to providing quality decision options is an appropriate method of combining, or fusing, these heterogeneous evidence sources. Since the development of belief function theory introduced by Shafer in the 1970s many combination rules have been proposed in the literature because in highly conflicting situations the emblematic Dempster's rule generates counter-intuitive and unacceptable results in practical applications. In this work, the Dezert-Smarandache theory (DSmT) will be explored, in particular the PCR5 and PCR6 rules of proportional conflict redistribution, and a simple long-distance pipe leakage monitoring method is developed to help in the development of a method for more complicated situations.

Comparison of effects on technical variances of computational fluid dynamics (CFD) software based on finite element and finite volume methods

Abstract Recently, many studies for flow characteristics have used commercial computational fluid dynamics (CFD) software to simulate flow phenomena in various fields. The aim of this study is to contribute to the discussion on the efficiency of finite element (FE) and finite volume (FV) methods, which have mainly used as CFD solvers for situations with the same number of mesh elements and geometries. We compared the accuracy of the results and the flow patterns among three different commercial codes – Ansys CFX, Fluent and ADINA, which are used in many fields. We calculated three-dimensional incompressible laminar flow problems with simple pipe and bifurcation models. Our results showed that FEM CFD codes (ADINA) were more influenced by the mesh type and quality compared to FVM CFD codes (Ansys CFX, Fluent). The computation time was found to be significantly shorter for the FVM compared to the FEM codes.

Optimization Design for Diameter in Irrigation Pipeline Network in Land Consolidation

In the process of land consolidation, most designers of low-pressure water delivery systems for irrigation purposes use very simple empirical pipe selection methods based on arbitrary concepts, without taking into account economic factors. These methods do not lead to an optimal solution.In this article an optimum design method to calculate economic pipe diameters was presented. Based on the existing optimization model, the design was aimed to maximally reduce the annual pipeline network cost, and calculate the optimum economic pipe diameters of the network. By calculating the pipe diameter of irrigation pipeline network in Panan coal mining subsidence area in Jiawang district, Xuzhou City, the land consolidation investment of irrigation pipeline network was 1148199 Yuan, while the investment was 1478808 Yuan calculated by planning method, with 22 % saved compared to the original plan. Comparison with traditional methods the new method has a good performance.

Computer aided estimation of fugitive emission rates and occupational air concentration in process design

European Union directives such as the Integrated Pollution Prevention and Control (IPPC) require inclusion of safety, environmental and health analyses in process design as part of strategies towards achieving sustainable process development. In petrochemical and organic chemical industries, which mostly handle volatile compounds, the most significant contributor to atmospheric releases is fugitive emissions that are mainly contributed by piping fittings and components. Fugitive emissions are not only of economic and environmental concern, but also a major source of background inhalative exposure to workers that may lead to various diseases including cancer. More people die every year from occupational diseases as compared to the number killed in industrial accidents. Therefore the estimation of occupational air concentration due to fugitive emission needs to be done early when developing a new process. Several methods for fugitive emissions estimation have been introduced which mostly involve manual calculations. Computer-based tools for such purpose however, are still lacking. Besides, the current methods mainly focus on the emission rates only but not on the process air concentrations. Computer aided methods for fugitive emissions assessment are highly in need, since now most of the design work is done by using computer aided process engineering (CAPE) tools. Therefore in this paper computer aided methods for quantifying fugitive emission rates and occupational air concentration are presented. Three methods are proposed for early design stages based on data available from simple process flow diagrams (PFDs), detailed PFDs or piping and instrumentation diagrams (P&IDs). The method becomes more comprehensive as it progresses from simple PFDs to P&IDs, since more process data are available later, which include plot plan, coordinates of the emission sources and local wind speed. Users however, can choose which method to use depending on the process information available in hand. The methods are demonstrated in a case study of product distillation system of toluene hydrodealkylation.

Wire Electrical Discharge Milling using a Wire Guide with Reciprocating Rotation

EDM is a useful method for machining hard materials. Particularly, ED-milling using a simple bar or pipe electrode is an attractive method to machine 3D cavities. However, it is difficult to suppress the electrode wear completely. On the other hand, in cases of WEDM and WEDG it is usually not necessary to consider the electrode wear. We can even use such materials like brass wire that wear easily. We developed a new method combining the advantages of ED-milling and WEDM/WEDG. It is named WED-milling (wire electrical discharge milling). In this method a wire guide with a hemisphere tip is used. The wire slides along the groove prepared on the surface of the tip. The wire guide is reciprocated in rotary state and moved along the designed path for generating the 3D shape. By this method, 3D machining similar to the mechanical milling with a ball end mill is realized. This method is free from the problems such as tool wear or the built-up edge in mechanical milling. In this paper, several machining properties of WED-milling are introduced.

Discussion of “Case Studies of Leak Detection and Location in Water Pipe Systems by Inverse Transient Analysis” by Dídia Covas and Helena Ramos

In a lecture about fundamental issues in numerical hydraulicsgiven within the theme “Frontiers in Hydraulics: ComputationalHydraulics” of the Iowa Hydraulics Colloquium, Liggett (1996)indicated the solution of transient flow in networks as a problemthat had not been studied as intensively as many other hydraulicsproblems. Moreover, Liggett voted for inverse analysis as thenext big push in numerical hydraulics. In the discussers’ opinion,this paper not only gives a valuable contribution in the field oftransient test-based techniques (TTBT) for simple pipe systemdiagnosis but also points out some crucial aspects that couldbe investigated more extensively. Precisely, to improve the per-formance of TTBT for the detection of possible anomalies(e.g., leaks, partial blockages, partially closed in-line valves,and illegal branches), the following questions arise: (1) why notcouple the ITA approach with a preliminary analysis of transientpressure data? and (2) why not generate controlled and sharppressure waves by means of proper devices instead of by maneu-vering valves?With regard to the first question, some benefits could beachieved by first locating the anomalies by analyzing the timehistory of the pressure (i.e., pressure signal,

파이프형 원심펌프의 성능특성에 관한 실험적 연구

The positive displacement pump and the regenerative pump are widely used in the range of low specific speed, [rpm, m3/min, m]. The positive displacement pump is not suitable for miniaturization and operation in high rotational speed. The regenerative pump has a problem with large leakage flow and low efficiency. While the centrifugal pump has advantages of high efficiency, miniaturization and high rotational speed, efficiency drops sharply with decrease in specific speed. Therefore the purpose of this study is to design a new type of centrifugal pump that has advantages of centrifugal pumps in operation in low specific speed. The name of this new type of pump was called `Pipe type centrifugal pump`, since the flow path through the impeller is simple circular pipe. Due to the simple shape of impeller, the manufacturing process is simple and cost is low. There is strong jet flow at the outlet of the impeller. This jet induces flow path loss, meridional dynamic pressure loss and mixing loss. Large disk friction makes the efficiency be limitted in the range of low specific speed. Even though the loss and the low efficiency, `Pipe type centrifugal pump` represents stable performance, affordable pressure ratio and efficiency better than that of other low specific speed pumps.

Vibration analysis of three-dimensional pipes conveying fluid with consideration of steady combined force by transfer matrix method

The application of transfer matrix method (TMM) to the vibration analysis of three-dimensional (3D) pipelines conveying fluid is performed in this paper. Based on the equations of motion, in which the steady combined force is essentially included, a 3D straight pipe element and a curved pipe element conveying fluid are formulated by introducing dynamic stiffness matrix in order to apply the TMM. The natural frequencies of simple pipe systems with straight or circular shape are calculated to demonstrate the validity of the proposed treatment. Using TMM, the natural frequencies, frequency response functions and instability of 3D-shaped pipeline systems are analyzed, representing some fresh results. It is shown that, in the application of TMM to the vibration analysis of curved or 3D pipelines conveying fluid, the steady combined force has to be included, otherwise the obtained results may be not reliable.

The didjeridu: Relating acoustical properties to players' reports of performance qualities

Relating objective acoustical measurements of an instrument, without a player, to the qualities reported by players is often a difficult goal in music acoustics. The didjeridu offers advantages in such a study because it is inherently ‘blind’—neither player nor researcher knows what is inside—and because there are wide variations in objective parameters. Here, seven experienced players reported several qualities and overall quality of 38 traditionally made didjeridus whose acoustic impedance spectra and overall geometry were measured. The rankings for ‘overtones’, ‘vocals’, ‘resonance’, ‘loudness’ and overall quality were all negatively correlated with the characteristic impedance of the instrument, defined as the geometric mean of the first impedance maximum and minimum. ‘Speed’ was correlated positively with the frequency of the lowest frequency impedance peak, near which the instrument plays. Assessments of geometrically simple PVC pipes yielded similar results. The overall ranking was highest for instruments with a low magnitude impedance, particularly in the 1-2 kHz range. This is the range in which players produce a strong formant in the radiated sound by varying vocal tract resonances with comparable ranges of impedance. This study and the researchers were inspired by the pioneering research in music acoustics by Neville Fletcher.

Fugitive emissions in chemical processes: The assessment and prevention based on inherent and add-on approaches

Fugitive emissions are among the major concerns of industrial process releases. The emissions cause problem to various aspects including the environment, health, and economic. Early evaluation of process hazards is beneficial because process can be made inherently benign at lower cost. This paper discusses two important aspects of fugitive emissions assessment during process design – the quantification and the prevention strategies.For the quantification part, three methods are presented for fugitive emissions estimation during the process design. They are tailored to data available in simple process flow diagram (PFD), detailed PFD, and piping & instrumentation diagram (PID). Such methods are needed as early emissions estimation allows production routes and process designs with lower emissions to be selected. The fugitive emissions estimation and methods to abatement are demonstrated on a benzene process case study. Valves are found to be the major emission source with 50% of fugitive emissions of process area in a base case of petrochemical process, in which no fugitive emission reductions are yet made. Pumps without mechanical seals come second with 30% and flanges with 8% of emissions. Inherently safer design keywords can be applied to prevent fugitive emissions in the process plants. Substitution is the most applicable keyword in fugitive emission reduction of existing plants.The emission rate calculations together with estimation of health risk give a sound background for the decision making on elimination of emissions at source through equipment and piping changes. The case study presented reveals that by substituting emission prone components by inherently low-leaking ones, the plant emissions can be reduced over 90% in practice. This is created mainly by replacing rising stem valves with ball valves, installing double mechanical pump seals or hermetic pumps and making changes in sampling and relief systems. Ideally by also changing flanges to welded connections, which is not viable for various reasons, the emissions could be reduced nearly to zero.

Water distribution network analysis under fuzzy demands

Looped pipe networks are analysed assuming that all the input variables have precise crisp values. If the hydraulic heads are to be determined, the water demands at the nodes, the diameters and the roughness coefficient of the pipes are considered known and crisp. The paper proposes a fuzzy set approach for addressing the uncertainty of the water demands at the nodes using the Newton–Raphson method for the analysis. In contrast with other studies which adopt the fuzzy approach for analysing the behaviour of the looped hydraulic networks, the proposed methodology exploits the monotony of the continuity equation at the nodes; therefore, the multicriteria optimisation procedure for handling fuzziness is not required. The application of the proposed methodology results in a range of hydraulic heads at the nodes of the network. This information is important for the designer and can be used to identify vulnerable areas of the network which may suffer from design pressure deviations. The proposed methodology is illustrated through a simple looped pipe network analysis exercise.

A simple approach to assessing copper pitting corrosion tendencies and developing control strategies

Localized corrosion of copper premise plumbing in drinking water distribution systems can lead to pinhole leaks, which are a growing problem for many homeowners. Despite the fact that water quality is an important factor associated with localized copper corrosion, good approaches for predicting the tendency of water to support localized corrosion and for assessing water treatment options to address problems are not available. The objective of this research was to determine the effectiveness of a simple pipe loop system, installed in a drinking water distribution system, in predicting localized copper corrosion and to assess treatment alternatives in drinking water. Visual examination of the internal surface of copper pipes positioned in the loop revealed signs of localized corrosion (isolated 3 mm diameter mounds of corrosion by-products) after only 72 days. Examination of pipe sections removed from the loops after 101 days clearly showed that localized corrosion was taking place. Cross-section analysis of the pipe showed pits as deep as 0.150 mm that were covered by a thin membrane and a mound of blue-green corrosion products. An ortho- and poly-phosphate blended chemical fed to a second pipe loop, prevented pitting attack, and produced different corrosion by-products. The study showed that simple, inexpensive copper pipe loops can be useful in predicting pitting tendencies of drinking water and in assessing the effectiveness of treatment alternatives.

Experimenting with a “Pipe” Whistle

A simple pipe whistle can be made using pieces of PVC pipe. The whistle can be used to measure the resonant frequencies of open or closed pipes. A slightly modified version of the device can be used to also investigate the interesting dependence of the sound frequencies produced on the orifice-to-edge distance. The pipe whistle described here allows students in a physics of music or introductory physics course to study an example of an “edge tone” device that produces discrete sound frequencies. From their textbooks, students likely know about standing waves produced by pipes or strings, as well as the resonant frequencies for open and closed pipes. To go a bit further, they can also learn how the frequency of the sound wave depends on the orifice-to-edge distance of the wind instrument.

Maximum Air Suction Into a Louvered Funnel Through Optimum Design

The rate of air suction into a louvered cylindrical funnel with lateral openings has been computed numerically by solving the equations of conservation of mass, momentum, and energy along with the two k-z turbulence closure equations. It was found that the air suction rate into a louvered funnel can be maximum for an optimum nozzle protrusion length into the funnel irrespective of the nozzle fluid temperature. There also exists an optimum funnel diameter (irrespective of the nozzle fluid temperature) and funnel height for which the air suction rate can be the maximum. Keeping the volume of the funnel constant, the shape of the funnel was changed to a frustum. It was found that an inverted frustum with a value of r1/r2 = 0.8 could suck the maximum amount of air compared to a cylindrical funnel of the same volume. The cylindrical sucking funnel has interestingly a much shorter entrance length compared to a simple pipe flow case with the same entrance Reynolds number. The entrance length for the sucking funnel is also a function of the nozzle fluid temperature, and a simple relation for the entrance length as a function of Ren and Tn/T∞ could also be developed for a sucking funnel. Numerical experiments were done for an inclined funnel to compute the mass suction into it. It was found that for Gr/Re2 ≤ 0.4 (where Gr is the Grashof number and Re is the Reynolds number) given by the funnel inclination had no effect on the rate of mass suction while for 0.4 < Gr/Re2 < 1 the funnel inclination had marginal influence. As the value of Gr/Re2 increased beyond 1 the influence of the funnel inclination on rate of mass suction was found to be significant.

Terahertz refractive index sensors using dielectric pipe waveguides.

A dielectric pipe waveguide is successfully demonstrated as a terahertz refractive index sensor for powder and liquid-vapor sensing. Without additional engineered structures, a simple pipe waveguide can act as a terahertz resonator based on anti-resonant reflecting guidance, forming multiple resonant transmission-dips. Loading various powders in the ring-cladding or inserting different vapors into the hollow core of the pipe waveguide leads to a significant shift of resonant frequency, and the spectral shift is related to the refractive-index change. The proven detection limit of molecular density could be reduced to 1.6nano-mole/mm3 and the highest sensitivity is demonstrated at around 22.2GHz/refractive-index-unit (RIU), which is comparable to the best THz molecular sensor [Appl. Phys. Lett. 95, 171113 (2009)].