Pipe Configuration Research Articles

Проблема изготовления труб по проектной информации

The article considers the problem of increasing the efficiency of shipbuilding production on the basis 
 of pipe manufacturing technologies by design information. The reasons that prevent the manufacture of pipes by design information and possible ways to eliminate them are analyzed. Great attention to the manufacture of pipelines is explained by the significant amount of pipeline work, which makes 10-12% of the total labor intensity of building 
 a ship, and on some projects - up to 14-17%. At the same time, the share of pipes manufactured in advance does not exceed 40%. The solution of the problem is considered in a historical retrospective taking into account modern realities, because the development and improvement of the technology of pipe production is one of the main important directions in the development of shipbuilding not only in Russia, but also in the world. Significant changes in the technology are associated with the widespread use of computing devices to improve the computer-aided design, technological preparation of production and the manufacture of pipelines according to design information. There has been carried out comparative analysis of pipe production efficiency using pipe bending machines, bent segments and straight sections. To form the pipe configuration, it is proposed to retain the traditional technology of pipe bending using pipe bending machines. Directions for further research in this area are identified and solutions are proposed, the implementation of which will help reduce construction time, reduce labor intensity and increase the productivity of pipeline work when fulfilling shipbuilding orders. Ensuring the reliability of design information is aimed at increasing the proportion of pipes manufactured in advance, regardless of the functional purpose of pipelines.

A critical review on renewable battery thermal management system using heat pipes.

The critical review presented here exclusively covers the studies on battery thermal management systems (BTMSs), which utilize heat pipes of different structural designs and operating parameters as a cooling medium. The review paper is divided into five major parts, and each part addresses the role of heat pipes in BTMS categorically. Experimental studies, numerical analyses, combined experimental and numerical investigations, optimum utilization of a phase-change material (PCM) with a heat pipe (HP), oscillating heat pipe (OHP), and micro heat pipes combined with PCM for Li-ion BTMS using heat pipes are presented. The usage of HP's and PCM can keep the temperature of the battery system in the desirable limit for a longer duration compared to other traditional and passive methods. More emphasis is made on how one can achieve a suitable cooling system design and structure, which may tend to enhance the energy density of the batteries, improve thermal performance at maximum and minimum temperature range. Arrangement of battery cells in a pack or module, type of cooling fluid used, heat pipe configuration, type of PCM used, working fluid in a heat pipe, and surrounding environmental conditions are reviewed. According to the study, the battery's effectiveness is significantly influenced by temperature. The usage of flat HPs and heat sink proves to be the best cooling method for keeping the battery working temperature below 50°C and reduces the heat sink thermal resistance by 30%. With an intake temperature of 25°C and a discharge rate of 1 L per minute, an HP that uses water as a coolant is also effective at regulating battery cell temperature and maintaining it below the permissible 55°C range. Using beeswax as a PCM in HPs reduces the temperature of BTMS by up to 26.62°C, while the usage of RT44 in HPs reduces the temperature of BTMS by 33.42°C. The use of fins along with copper spreaders drastically decreases the temperature capability of HPTMS by 11°C. MHPA shows excellent performance in controlling the battery temperature within 40°C. The effective thermal management can be done by incorporating heat pipe alone or by coupling with liquid cooling or metal plate. However, extensive and extended research is required to improve thermal management to safely and effectively use the battery for day-to-day applications.

Turbulent heat transfer in pipes with increased roughness through shavings of helical ribs

Large-eddy simulations of mircrostructured pipes are carried out in this study. The pipes are helically ribbed with several starts from which shavings are cut out along the rib. A Reynolds number of 16,000 and a Prandtl number of 9 are applied. Cyclic boundary conditions are used to simulate an infinitely long pipe and a LES turbulence model is applied. The results show that both the number of starts and the distance of the shavings along the rib, have an impact on turbulence and heat transfer. An optimum was found for the number of starts regarding heat transfer. The heat transfer area increases for a higher number of starts, but the flow-related heat transfer decreases. Thus, an optimal arrangement of starts was identified for this pipe configuration. The variation of the arrangement showed that the pressure loss can be reduced by an inline configuration, whereby the heat transfer is only slightly decreased. It can be shown that the simulations can contribute to optimising complex structures in the future and thus accelerate the development process of new geometries. It can be shown that the development of new heat exchanger pipes is also possible with complex structures, this can be demonstrated here for the first time for structures that can actually be fabricated.

A data-based reduced-order model for dynamic simulation and control of district-heating networks

This study concerns the development of a data-based compact model for the prediction of the fluid temperature evolution in district heating (DH) pipeline networks. This so-called “reduced-order model” (ROM) is obtained from reduction of the conservation law for energy for each pipe segment to a semi-analytical input–output relation between the pipe outlet temperature and the pipe inlet and ground temperatures that can be identified from training data. The ROM basically is valid for generic pipe configurations involving 3D unsteady heat transfer and 3D steady flow as long as heat-transfer mechanisms are linearly dependent on the temperature field. Moreover, the training data can be generated by physics-based computational “full-order” models (FOMs) yet also by (calibration) experiments or field measurements. Performance tests using computational training data for a single-pipe configuration demonstrate that the ROM (i) can be successfully identified and (ii) can accurately describe the response of the outlet temperature to arbitrary input profiles for inlet and ground temperatures. Application of the ROM to two case studies, i.e. fast simulation of a small DH network and design of a controller for user-defined temperature regulation of a DH system, demonstrate its predictive ability and efficiency also for realistic systems. Dedicated cost analyses further reveal that the ROM may significantly reduce the computational costs compared to FOMs by (up to) orders of magnitude for higher-dimensional pipe configurations. These findings advance the proposed ROM as a robust and efficient simulation tool for practical DH systems with a far greater predictive ability than existing compact models.

Thermo-hydro-mechanical behavior of energy barrettes: Field experiments and numerical simulations

Over the past two decades, the thermo-hydro-mechanical behavior of earth-contact structures such as piles, walls, slabs, and tunnels, which simultaneously provide structural support and energy supply, has been studied through various field experiments and numerical simulations. These endeavors have built an understanding of the behavior of so-called energy piles, energy walls, energy slabs, and energy tunnels. This paper explores the thermo-hydro-mechanical behavior of a novel class of earth-contact structures that has the specificity of providing structural support and renewable energy to tall buildings: energy barrettes. This study particularly presents the first field experiments and 3-D time-dependent numerical simulations of energy barrettes. The work investigates the thermo-hydro-mechanical behavior of energy barrettes for a comprehensive set of variables: geometric variables (i.e., pipe configuration, barrette aspect ratio, and barrette section ratio), site variables (i.e., barrette–soil stiffness ratio and ground effective thermal conductivity), and operational variables (i.e., flow rate of the fluid circulating in the pipes). The obtained results expand the current knowledge base to analyze the behavior of energy barrettes in multiple situations that are likely to be encountered in practice and highlight markedly non-uniform temperature, displacement, and stress fields within and around such foundations.

Effect of Heat Pipe’s Configuration in Managing the Temperature of EV Battery

Because of their high energy density and long cycle life, lithium-ion batteries are commonly employed in electric cars. As battery performance and life are highly dependent on temperature, it is critical to maintain the optimum temperature range. A battery thermal management system (BTMS) is critical for controlling the thermal behaviour of the battery. Air cooling, liquid cooling, direct refrigerant cooling, phase change material (PCM) cooling, and heat pipe cooling are all BTMS strategies. Heat pipes come in a variety of sizes and configurations that can be employed in the BTMS and many studies have proven the feasibility of using heat pipe as the electric vehicles’ BTMS. However, there are many aspects of the design and configuration of the heat pipe that could affect the overall thermal performance of the heat pipe BTMS such as its length, diameter, evaporator and condenser lengths, tilt angle, types of heat pipes and working fluids. In this work, a numerical study was conducted to investigate the effect of heat pipe’s diameter, number of heat pipes and the types of heat pipes on the thermal performance of the heat pipe BTMS. The diameter of the heat pipe varies between 6 – 12 mm, the number of heat pipes varies from 2 – 10 and the type of heat pipe considered in this work is straight heat pipe. The thermal performance of the heat pipe is measured by the maximum battery temperature and the thermal resistance at different battery heat generation rate in the range of 10 - 30W. The simulation model was validated against experimental data and results indicate excellent agreement between simulation and experimental data. Simulation results shows that the greater the diameter, the lower is the battery temperature. By increasing the heat pipe’s diameter, the battery temperature can be reduced by at least 10% or 3.4°C. Temperature reduction of at least 12.7% was observed when the number of heat pipes used in the BTMS increases.

Performance of a Heat-Pipe Cooled Concentrated Photovoltaic/Thermoelectric Hybrid System

Compared to traditional one-sun solar cells, multijunction concentrator cells operating under concentrated solar radiation are advantageous because of their high output and low cooling costs. Such a concentrator PV requires a cooling technique to maintain its performance and efficiency. The performance of a multi-junction concentrator photovoltaic cell of efficiency around 33%, operating under concentrated solar radiation (160–250 sun), has been tested. Heat pipes were used in this study as a fast and efficient way of rejecting heat accumulated in the cells. In this work, the evaporator side of the heat pipe was set in thermal contact with the back side of the solar cell such that the excess heat was transferred efficiently to the other side (condenser side). To positively utilize such excessive heat, two thermoelectric generators were thermally attached to either side of the condenser of the heat pipe, and each was attached to a fin-shaped heat sink. Four different cooling configurations were tested and compared. The net power obtained by this concentrator solar cell employing two types of TEG with different lengths as a cooling alongside two thermoelectric generators for heat-to-electricity conversion was 20% and 17%, corresponding to the long and short heat pipe configurations, respectively, compared to traditional a heat sink only configured at an optical concentration of 230 suns.

CFD investigation of pressure drop reduction in hydrotransport of multisized zinc tailings slurry through horizontal pipes

Zinc is an important metal useful in hydrogen production. Mining of zinc also involves zinc tailings disposal using pipeline transportation which is an energy- and water-intensive process. In this study, the multisized slurry of zinc tailings is modeled using CFD to investigate the flow field characteristics in a straight horizontal pipe fitted with swirl-inducing sections. The primary objective was to study the pressure drop by adding swirl-inducing pipe of different numbers of lobes to the conventional pipe. Nine configurations of multi-lobed swirl-inducing pipes were studied for transport characteristics of solids at three flow rates and three overall solids concentrations. Eulerian-Eulerian modeling with the RNG k-ε turbulence model is employed for simulations. The numerical model is validated for pressure drop against available experimental results, and excellent agreement is achieved. The study shows that 10-lobed swirl-inducing section fitted to the conventional pipe reduces the pressure drop by nearly 35%, offering the potential for further exploration.

In-field performance of continuous flight auger (CFA) energy piles with different configurations

In order to face the national energy crisis in Brazil, the use of geothermal energy piles (GEP) integrated with heat pumps is an attractive and cost-effective solution for the building cooling demand. On the other hand, there are very few field studies on the thermal performance of GEP systems in Brazilian soils and climate conditions, and for this reason, the implementation of this technology is still a challenge. Motivated by this need, continuous flight auger (CFA) energy piles were constructed to support a building in São Paulo city, and an experimental study, described in this paper, was carried out to provide useful data for the design of these GEPs. This work examined two key aspects of the design of GEP systems: (1) the influence of the heat exchange pipe configuration, and (2) the thermal response of GEPs and their effect on nearby piles installed in multi-layered ground. For this study, thermal response tests (TRTs) were conducted on four GEPs constructed with different pipe configurations, installed in a saturated sandy deposit intercalated by soft organic clay layers. The results obtained showed that: (i) the influence of pipe configuration on the GEP heat transfer is more significant during the first hours of pile heating process, and decreases with time due to the thermal interference between the pipe loops; (ii) the GEP temperature profile is impacted by the presence of soil layers of highly different thermal conductivities and groundwater flow velocities; and (iii) the temperature variation of nearby piles was also affected by the thermal characteristics of the soil layers, and therefore it should be considered for the structural design of GEPs.

Experimental and numerical investigation of solid-solid phase change material assisted heat sink with integrated heat pipe for electronic cooling

Advancements in phase change materials (PCM) technology offer adaptable solutions for challenging high heat dissipation problems in electronic devices. In this work, the influence of Neopentyl Glycol (NPG) as PCM having solid-solid phase transition on the functioning of heat pipe assisted heat sink is studied. Experimental and numerical investigation was performed on the transient thermal performance of heat pipe integrated PCM-assisted heat sink application with forced air cooling. The heat pipe's evaporator section is in contact with PCM- assisted heat sink, while condenser section is exposed to the ambient. Investigations were carried out at power levels of 9–13 W, corresponding to an equivalent heat flux range of 2.5–3.5 kW/m2 and with PCM filling of 33, 66 and 99 % of the heat sink volume where without integration of PCM and heat pipe in heat sink as the reference configuration. PCM-assisted heat sink and heat pipe configurations outperformed other configurations based on charging period for all experimental parameters with a maximum enhancement ratio of 3.29. Heat sink assembly comprising 99 % PCM with heat pipe gives the most significant results on comparison with all other configurations, whereas the assembly without heat pipe showed the best results for 66 %.

KINERJA GAS PENUKAR PANAS ALIRAN BALIK SHELL AND TUBE UNTUK PENGERING PERTANIAN

Abstract—One of the important post-harvest processes of rice is drying. Drying is divided into two, namely natural drying (using sunlight) and artificial drying (using tools). In this study drying utilizes heat from a biomass furnace and a configuration of heat exchanger pipes. Where the utilization of heat and the configuration of heat exchanger pipes in the design can increase thermal efficiency because the exhaust hot air mixed with smoke can still be used for drying. The configuration of the heat exchanger pipe greatly influences the expected moisture content level. The purpose of this study was carried out to determine the performance of the shell and tube counter flow heat exchanger for agricultural dryer gases with a heat source from biomass and to find the effect of the configuration of the heat exchanger pipe arrangement on the working process of the drying machine. This research is an experimental test of the performance of heat exchange pipes with a heat source from a biomass furnace. The exchange pipe performance parameters that must be known are temperature and time. The method used in this study refers to experimental and descriptive methods, namely research conducted in a systematic, factual and accurate manner. The results of this study are that the heated air flow rate affects LMTD, heated air outlet temperature, heat transfer coefficient, and efficiency, with variations in the heated air flow rate of 0.11 kg/s, 0.16 kg/s, 0.20kg/s, 0.24kg/s. Highest efficiency of 94% at a heated air flow rate of 0.24 kg/s. and the smallest efficiency of 74% is found in the value of the heated air flow rate of 0.11 kg/s.
 Keywords : dewatering, biomass, pipe configuration, heat exchanger pipe

Numerical study on the thermal-induced mechanical behavior in deep energy diaphragm wall (EDW): The long-term soil elastoplastic effects

The energy diaphragm wall (EDW) attracted increasing attention due to its high energy exchange rate and low space occupation. The current research on EDW primarily focused on its heat exchange capacity and performance. The elastoplastic effects on thermal-induced mechanical behavior caused by soil were neglected, which might underestimate the wall deflections in deep EDW due to the asymmetrical surrounding pile height pressure on both sides. This paper investigated the thermal performance and the induced mechanical behavior in deep energy diaphragm wall (EDW) based on the finite element analysis method (FEA) by the COMSOL Multiphysics software. Firstly, the thermal performance of varied pipe configurations (e.g., single U-shaped; W-shaped; double-U shaped; horizontal arrangement) was studied. Then it was followed by a study of a single heating–cooling cycle with a single U-shaped pipe, where the elastoplastic impact of the soil in the deep EDW was observed. Moreover, a parametric analysis with a long operation period (30 years) perspective was proposed regarding the heat load modes, the pipe buried locations, the air temperature of the adjacent underground space, and the excavation level. Results revealed that the heat transfer process caused an obvious impact on thermal-induced mechanical behavior. Higher levels of heat injection (Case 3) and extraction (Case 2) both led to a relatively large wall deflection after 30 years. The horizontal displacements at the top of the wall under Case 3 and Case 2 were up to 30.5 mm and 25.9 mm, respectively, while 22.9 mm under balanced case (Case 1) and 21.1 mm under the no heat load case (Case 0). When the pipe was close to the side of the excavation, the plastic deformation was about 1.25 times greater than that on the soil side, where the thermal contraction effects were emphasized. Besides, the air temperature in the underground space caused a small impact on the plastic strain in the soil domain. Because of the enhancement in the heat transfer process from the air to the wall while the air temperature increased, resulting in the average wall temperature raised. In addition, the influence caused by the excavation levels was quite evident. The deeper the excavation level, the easier the plastic strain to occur. This paper proposed a new perspective for understanding thermal-induced mechanical behavior in deep EDW, especially the long-term soil elastoplastic effects, which exerted a complex impact on the deformation variation of the diaphragm wall.

Study Investigates Multiphase Flow in Circular and Triangular Pipes

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 208101, “Multiphase Flow in Circular and Triangular Pipes: Examining Flow Characteristics, Sand Erosion, and Heat Transfer Through Computational Fluid Dynamics and Experimental Work,” by Ronald E. Vieira, Thiana A. Sedrez, and Siamack A. Shirazi, SPE, The University of Tulsa, et al. The paper has not been peer reviewed. _ The authors present a survey of air/water and air/water/sand flow through circular and triangular pipes. The main objective of this investigation is to study the potential effects of triangular pipe geometry on flow patterns, slug frequency, sand erosion in elbows, and heat transfer in multiphase flow. Introduction The complete paper summarizes several important benefits of triangular pipes as compared with circular pipes in multiphase flow. First, a survey of horizontal multiphase air/water flow through circular and triangular pipes is presented. Second, the erosion patterns in triangular elbow geometry are examined experimentally and predicted computationally using existing erosion models. The results are compared with circular elbows for steel materials. Initially, an experimental investigation was performed using flow visualization with a paint-removal study to determine the location where particles impinge and lead to erosion. Erosion-measurement experiments are also conducted in a flow loop containing liquid and 300-µm sand particles. The experimental studies were followed by computational fluid dynamics (CFD) erosion modeling for liquid/sand and liquid/gas/sand flows in circular and triangular elbows. Third, an attempt is made to analyze the effect of circular and triangular pipe configurations on heat transfer at constant wall temperature and under the influence of different Reynolds number values. The analysis was performed numerically using CFD for turbulent and laminar flow with water at two different viscosities. Experimental Setups The main objective of the first set of experiments was to study the potential effects of triangular pipe geometry on flow patterns and slug frequency in gas/liquid flows. The experimental facility and methodology are detailed in the complete paper. The setup consisted mainly of a pump, tank, separator, and test-loop section (pipes). The water flow rate (containing particles) was measured by timing the liquid volume loss from the tank. Measurements were repeated three times, and the averaged measured time was used. The gas-flow rate was measured using a digital vortex flowmeter. Experiments were performed horizontally and near atmospheric pressure conditions. The circular test section consisted of a 2-in.-inner diameter, 28-ft-long clear acrylic pipe. The triangular test section was formed from three 7-ft-long, 2.7-in.-wide sheets of cast acrylic. The effect of corners of the triangular pipe on the liquid distribution compared with round tubes was investigated using two different orientations of triangular pipe, apex upward and downward. Detailed videos and slug-frequency measurements were collected for horizontal air/water flow through the round and the triangular clear pipes to identify flow patterns. The slug frequency was measured by analyzing the videos.

Enhanced turbulent convective heat transfer in helical twisted Multilobe tubes

Enhancing heat transfer performance has been the main interest in the thermal engineering field. Various enhancement methods have been proposed, including twisted and Multilobe tubes. Nevertheless, no study investigating the enhancement by combining both strategies has been reported. This study is thus conducted to numerically evaluate the turbulent convective heat transfer performance of Newtonian fluid flow in a helical twisted Multilobe tube. The model is validated against experimentally measured data of similar configurations. The effects of Multilobe geometries and Reynolds number were evaluated. The results revealed that combination of twisting and Multilobe profile enhance the secondary flow and, in turn, increases the convective heat transfer performance for straight geometries by up to 6.76%, while the addition of twisting of the tubes has a marginal effect on the heat transfer performance in helical models. Furthermore, the variation of the number of lobes does not lead to significant changes in the heat transfer performance (less than 2% difference). Overall, bilobe cross-section shows superior performance in terms of overall performance when it is combined with a helical tube (1.08) or twisting (1.002) only, while pentalobe cross-section has better performance index in sophisticated flow with both helical tube and twisting of tube (1.037). Additionally, correlations are developed to predict the friction factor and Nusselt number in straight and helical tube. To find optimum configurations, Neural Network (NN) models are developed based on the CFD result. By using multi objectives optimization, it was found that the circular straight pipe configurations with and without a twist are the ones closest to the optimum solutions. Meanwhile, helical pipe without a twist is the closest to the optimum solutions. These observations are aligned with the insights obtained from the CFD analysis.

Level swell analysis of stagnant water pool in filtered containment venting systems

A filtered containment venting system (FCVS) prevents over pressurization of containment vessel and releasing of radioactive materials during the severe accidents in nuclear power plants. During the venting process, it has been reported that the two-phase mixture level in a wet FCVS tends to swell and fluctuate. The behaviors depend on inlet/boundary conditions and physical properties of the injected gas, which vary as the accident progresses. Proper controlling and monitoring of the FCVS pool water level is crucial because it affects filtration performance including scrubbing process and thermal-hydraulic stability. In order to investigate this phenomenon, the current study proposes a set of nitrogen and steam injection experiments using a vertical pipe with a diameter of 105 mm to evaluate the effects of flow conditions and physical properties of gases. Drift flux analysis was carried out to predict the two-phase mixture water level and its fluctuations. The experimental two-phase mixture level was consistent with the values predicted by the drift flux model for nitrogen and steam injection, and the model's capability was confirmed for the system pressure ranging from atmospheric to 0.20 MPa and initial water level ranging from 0.6 to 2.6 m for both small and large diameter pipe configurations. The fluctuation amplitudes in the current experiment were smaller than those observed in experiments conducted on small-diameter pipes. The mean two-phase mixture water level increased upon pressurization of the scrubbing pool. However, it was found that the effect of pressurization on the two-phase mixture level fluctuation amplitude was negligibly small.

Comparing Corrosion Control Treatments for Drinking Water Using a Robust Bayesian Generalized Additive Model

Pipe loop studies are used to evaluate corrosion control treatment, and updated regulatory guidance will ensure that they remain important for drinking water quality management. But the data they generate are difficult to analyze: nonlinear time trends, nondetects, extreme values, and autocorrelation are common attributes that make popular methods, such as the t- or rank-sum tests, poor descriptive models. Here, we propose a framework for describing pipe loop data that accommodates all of these challenging attributes: a robust Bayesian generalized additive model with continuous-time autoregressive errors. Our approach facilitates corrosion control treatment comparisons without the need for imputing nondetects or special handling of outliers. It is well suited to describing nonlinear trends without overfitting, and it accounts for the reduced information content in autocorrelated time series. We demonstrate it using a 4-year pipe loop study, with multiple pipe configurations and orthophosphate dosing protocols, finding that an initially high dose of orthophosphate (2 mg P L–1) that is subsequently lowered (0.75 mg P L–1) can yield lower lead release than an intermediate dose (1 mg P L–1) in the long term. Water utilities face difficult trade-offs in applying orthophosphate for corrosion control, and better models of pipe loop data can help inform the decision-making process.

Stationary Gas Dynamics and Heat Transfer of Turbulent Flows in Straight Pipes at Different Turbulence Intensity

The gas-dynamic and heat-exchange behaviours of air flows in gas-dynamic systems have a significant impact on the efficiency and environmental performance of most technical equipment (heat engines, power plants, heat exchangers, etc.). Therefore, it is a relevant task to obtain reliable experimental data and physical laws on the influence of cross-sectional shape and initial turbulence intensity on gas dynamics and the level of heat transfer. In this study, data were experimentally obtained on the instantaneous values of the local velocity and local heat transfer coefficients of stationary air flows in straight pipes with circular, square, and triangular cross-sections at different initial values of the turbulence intensity. The measurements were carried out with a constant temperature hot-wire anemometer, thermocouples, and pressure sensors. Based on the research results, data on the turbulence intensity and averaged local heat transfer along the length of pipes with different cross-sections were summarised. It has been established that turbulence intensity in a square pipe is up to 40% higher than in a round channel; in a triangular channel, on the contrary, it is up to 28% lower. After the air flow’s initial turbulence, the relaxation of the flow in square and triangular pipes occurs faster than in a round channel. It is found that the initial intensity of turbulence leads to an increase in the averaged local heat transfer, which is typical of all investigated pipe configurations and initial conditions.

Heat gain in an internally dimpled tube heat exchanger - a numerical investigation

Many researchers have looked at heat transfer improvement methods utilizing circular dimpled pipes, surfaces, and other methods in the past. The size and position of dimples, for example, have a major influence on the pipe's flow and thermal properties. Five internally dimpled pipe configurations were analyzed in this computational research. The flow was simulated using ANSYS Fluent 16, with water as the working fluid and steel pipes with internal dimples. The effect of dimple number and diameter on flow and thermal parameters was studied with the five different internal dimple configurations and compared them with plain tube heat exchanger thermal performance under similar conditions. Internal dimples (inside protrusions in tube heat exchanger) resulted in a larger pressure drop in the path of flow from entry to exit. It was discovered that dimples increased the pipe heat exchanger's heat transfer coefficient when compared to the plain tube heat exchanger. A higher pressure loss than plain pipe heat exchangers (HE) was found although the thermal performance was more than that for a plain pipe. The Reynolds number of flows was changed as a result of the pressure drop. When the Reynolds number was lower, the friction factor was found to be higher, resulting in increased heat exchange in the experiment. The results of the numerical analysis for the tube HE with dimples indicate that dimples help mixing of flow in the tube HE and a growth of thermal boundary layer which enhance heat between the hot fluid and cold fluid through the tube HE wall.

Joint geomorphological and geophysical (electrical resistivity) investigation for the configuration of soil pipe

Soil piping is a complex mechanism of subsurface soil erosion, which results underground conduits (cave/tunnel) of varying dimensions. Soil piping associates with severe consequences, such as land subsidence and land slide. Therefore, the investigation of soil pipe is crucial. However, the study of soil pipe is challenging unless characteristic surficial evidences of the pipe are available. Based on the surficial evidences, soil pipe can be configured with geophysical techniques which in-turn aid in designing precursory measures. Therefore, in the present study, we carried out a combined geomorphological and geophysical investigation to configure the soil pipe at Kinanoor village, Kasaragod, Kerala, India. Based on the vital geomorphological information, we carried out resistivity survey and configured an underground soil pipe of diameter ∼6.5 to 7 m that is seated ∼3 m beneath the surface. This hollow pipe is underlain by the only accessible road of that locality which makes the road vulnerable for transportation. Therefore, a bridge like structure is recommended to construct at the pipe location to stabilize the risk factor. Since the study area is situated on a fringe-slope, the geomorphological investigation points out that the disturbance in natural course of the drainage system and the accumulation of water in the up-slope area due to the man-made activities might act as potential causes for the piping in the area. Therefore, it is suggested not to disturb the natural course of the drainage which may lead to subsidence of the area in future.

Optimized structural parameters and heat extraction capacity of a mixing device for constant pressure CO2 mineralization using alkaline waste.

Alkaline waste such as calcium carbide slag is an ideal material for mineralizing CO2 and promoting atmospheric carbon reduction. In this study, the structural parameters of a mixing device and a thermal extraction method for the high-efficiency mineralization of CO2 using alkaline waste were optimized. First, the influence of structural parameters was studied by means of numerical simulation, and it was found that when the length-diameter ratio, blade angle, spacing, and diameter of the mixing device were 3, 15, 6 cm, and 14 cm respectively, 2.14 t CO2 can be mineralized within 1 h. The amount of heat extracted from mineralization of 1 t CO2 reached 189.60 MJ. In addition, the winding configuration of the heat pipe, which is beneficial for extracting more reaction heat, was optimal, and a model of the relationship between the heat pipe outlet water temperature and flow velocity at the outlet of the heat pipe was established. This study provides theoretical guidance for the field application of alkaline waste for high-efficiency mineralization of CO2, which can accelerate the realization of peak CO2 emissions and carbon neutrality.