Inside Pipe Research Articles

Numerical simulation on heat transfer inside and outside of vertical buried pipes based on two-model order reduction methods

In this article, two model order reduction (MOR) methods of Krylov subspace and Laguerre orthogonal polynomials were employed to the numerical simulation of heat transfer characteristics of ground heat exchangers and surrounding ground. The results show that the relative errors between the direct solution and two MOR methods are less than 0.1% under more than certain orders. Considering both the relative errors and time consumptions, for two MOR methods, it is workable to take about 1% of the original system order as the reduced system order. The larger the nodes of space and time, the more obvious the efficiency of two MOR methods.

Efficient Image Reconstruction Algorithm for ECT System Using Local Ensemble Transform Kalman Filter

One of the vital processes that should be monitored and analyzed continuously in the oil-gas and petroleum-related industries is the multi-phase flow inside pipes. Multi-phase flow means flowing two or more phases of gas, liquid, or solid inside a pipe. Electrical Capacitance Tomography (ECT) is a feasible and economical solution for monitoring dynamic applications. The ECT system offers the benefits of no radiation, non-intrusive, and non-invasive. Despite its potential, ECT systems deployment’s major limitation is the crucial need to develop rapid image reconstruction algorithms. In this paper, a Local Ensemble Transform Kalman Filter (LETKF) is developed as a non-linear system estimator for reconstructing images in the ECT system. This method manages each node of the model independently by assimilating only the observations at a predefined distance. The localized approach of the LETKF gives it high computational efficiency allowing it to be applied to large dynamic systems. A quantitative analysis using Image Error (IE) and Coefficient Correlation (CC) measures has been applied to prove the effectiveness of the proposed algorithm. Indeed, the IE has been significantly decreased (around 62%), and the CC greatly increased (around 58%). Then, the influence of the noise was discussed. The results are promising and prove the algorithm feasibility.

Functional coatings via isocyanate-cured phenolics for anti-graffiti and via benzoxazines for high-temperature and high-pressure (HTHP) applications

In this work centering on phenolic chemistry, we investigated isocyanate and benzoxazine modified phenolic powder coatings aimed to better address a couple of industrial applications. In one aspect, allied polyurethane formulations were developed using phenolic hydroxyl-isocyanate reactions and shown to outperform conventional aliphatic polyol-isocyanate coatings for graffiti resistance. Variants like phenol hydroxyl equivalent weights and molecular weights of phenolic resins were examined. In another aspect intended for oil and gas downhole drill pipe interior linings, novel fusion bonded benzoxazine/ epoxy/ phenolic formulations, with or without an acid catalyst, exhibited excellent adhesion, toughness and process-ability, in addition to greatly reducing cure requirements versus benzoxazine self-polymerization. Applicable rheology and kinetics were quantified, revealing characteristic flow and cure behaviors facilitating formulation optimization. Moreover, coating modules of isocyanate-cured benzoxazines and benzoxazine-bismaleimide were proactively established via effective catalysts.

An alternative approach for robot localization inside pipes using RF spatial fadings

Accurate robot localization represents a challenge inside pipes due to the particular conditions that characterize this type of environment. Outdoor techniques (GPS in particular) do not work at all inside metal pipes, while traditional indoor localization methods based on camera or laser sensors do not perform well mainly due to a lack of external illumination and distinctive features along pipes. Moreover, humidity and slippery surfaces make wheel odometry unreliable. In this paper, we estimate the localization of a robot along a pipe with an alternative Radio Frequency (RF) approach. We first analyze wireless propagation in metallic pipes and propose a series of setups that allow us to obtain periodic RF spatial fadings (a sort of standing wave periodic pattern), together with the influence of the antenna position and orientation over these fadings. Subsequently, we propose a discrete RF odometry-like method, by means of counting the fadings while traversing them. The transversal fading analysis (number of antennas and cross-section position) makes it possible to increase the resolution of this method. Lastly, the model of the signal is used in a continuous approach serving as an RF map. The proposed localization methods outperform our previous contributions in terms of resolution, accuracy, reliability and robustness. Experimental results demonstrate the effectiveness of the RF-based strategy without the need for a previously known map of the scenario or any substantial modification of the existing infrastructure.

CFD Analysis of Heating Pipe System from Flat Panel Display Devices

This research was conducted on numerical analysis using CFD software in forced vibration analysis of heating pipe under non uniform internal pressure. In order to have competitiveness in the enlarged OLED market, a large display fabrication technology is required. In this paper, a preliminary investigation was carried out for heating pipes using different CFD models available in FLUENT. It sets the calculation model of heat pipe OLED production process according to the characteristics of heat transfer of heat pipe, field distribution inner or outside of pipe reasonably and accurately by FULENT software. It is shown that pressure distribution on the inside of heating pipe caused by inner flow. The vibration analysis using ABAQUS program is employed to demonstrate the characteristic of vibration for each different boundary condition

A Novel Centralization Method for Pipe Image Stitching

The creation of unwrapped stitched images of pipework internal surfaces is being increasingly used to augment routine visual inspection. A significant challenge to the creation of these stitched images is the need to estimate the pose and position of the camera for each frame, which is often alleviated through the use of a mechanical centralizer to ensure the camera is held in the center of the pipe. This article proposes a novel method for image centralization and pose estimation, which is particularly beneficial to circumstances where mechanical centralization is impractical. The approach involves post-inspection centralization of the captured video, by first estimating the probe's position relative to the pipe, using an integrated laser ring projector combined with the camera sensor, and then using this position to unwrap the image, so it produces an undistorted view of the pipe interior (equivalent to unwrapping a centralized view). These unwrapped images are then stacked to produce a stitched image of the pipe interior. In this paper pose estimation was successfully demonstrated to have a 90% confidence interval of ±0.5 mm and ±0.5° in translation and rotation changes. This pose estimation is then used to create stitched images for both a visual test card image mounted inside a pipe and an aluminum pipe sample with artificial defects, in both cases demonstrating near equivalent results to those obtained using traditional mechanical centralization.

Laminar Forced Convection in Viscous Shear-Thinning Liquid Flows Inside Circular Pipes: Case for a Modified Power-Law Rheology

Abstract Laminar forced convection in viscous, non-Newtonian polymeric liquids that exhibit pseudoplastic or shear-thinning behavior is characterized. The fluid rheology is characterized by a new asymptotic power-law (APL) model, which appropriately represents extensive data for apparent viscosity variation with shear rate—from the low-shear constant-viscosity plateau to shear thinning at high shear rates. This is contrasted with the traditional Ostwald-de-Waele or power-law (PL) model that invariably over-extends the pseudoplasticity in the very low shear-rate region. The latter's limitations are demonstrated by computationally obtaining frictional loss and convective heat transfer results for fully developed laminar flows in a circular pipe maintained at uniform heat flux. The Fanning friction factor and Nusselt number, as would be anticipated from the rheology map of pseudoplastic fluids, are functions of flow rate with the APL model unlike the Newtonian-like constant value obtained with the PL model. Comparisons of the two sets of results highlight the extent of errors inherent in the PL rheology model, which range from 23% to 68% for frictional loss and 3.8% to 13.7% for heat transfer. The new APL rheology model is thus shown to be the more precise characterization of viscous shear-thinning fluids for their thermal processing applications with convective heat transfer.

Comparative numerical study on pressure drop in helically coiled and longitudinally C-shaped pipes

In the present work, the shear stress transport (SST) $$k - \omega$$ model is used to simulate internal turbulent flows in curved tubular heat exchangers and the resulting friction factors $$C_{f}$$ are calculated. A helically coiled configuration was used in the validation process of the model that showed a good agreement between numerical results of the friction factors $$C_{f}$$ and the standard experimental correlations of the literature, with a maximum relative error of 4.24%. A comparative study was performed to investigate the possibility of applying friction factor correlations, established mainly for helical coils, to longitudinally C-shaped pipes. Preliminary results confirm the inability of coil-specific correlations to predict the friction factor $$C_{f}$$ inside C-shaped pipes. It was also noted that, unlike helical coils, the C-shaped pipe friction factor appears to be affected by ratios other than the curvature ratio as highlighted in this study by introducing the effect of the amplitude ratio $$\beta$$ defined as the ratio of the amplitude to the curvature radius.

Turbulent Flows Inside Pipes Equipped With Novel Perforated V-Shaped Rectangular Winglet Turbulators: Numerical Simulations

Abstract In this study, computational simulations have been performed to investigate the turbulent characteristics and energy consumption through heat exchanger tubes equipped by new perforated V-shaped rectangular winglet (PVRW) turbulators. The effects of the holes intensity on the velocity and temperature contours are additionally investigated. The Reynolds number, hole diameter ratio, and the number of holes selected are in the range of 5000 ≤ Re ≤ 18,000, 0 ≤ DR ≤ 0.40, and 0 ≤ N ≤ 14, respectively. Renormalization group (RNG) k–ε turbulent model which is a finite volume solver is utilized for the computational fluid dynamics (CFD) simulation. It was noticed that the proposed perforated turbulators could considerably intensify the thermal performance compared to typical VRW inserts. It is found that the recirculating flow generated by the PVRW augments the fluid mixing and transfers the heat from the pipe walls to the core of the tube. The simulations illustrate that the amount of heat transfer enhances 25.2% reducing the DR from 0.4 to 0.13 at Re = 18,000 and N = 14. Also, using PVRW turbulators with N = 7 and DR = 0.26 augments the average Nusselt number around 354.3% compared to the circular pipe without inserts. The highest thermal efficiency parameter of η = 2.25 could be obtained at Re = 5000 for the heat exchangers fitted by vortex generators with N = 14 and DR = 0.26.

Fate and migration of polybrominated diphenyl ethers in a workshop for waste printed circuit board de-soldering.

Polybrominated diphenyl ethers (PBDEs) are released from the recycling process of PBDE-containing waste printed circuit board (WPCB), but studies on the mechanism of PBDE emission and migration are limited. In this study, PBDE concentrations in particulate matter (PM), dust, and fumes collected in a pilot-scale workshop for the WPCB de-soldering process were measured, and PBDE emission after gas treatment was estimated. The results showed that the mean concentrations of ∑8PBDEs in TSP and PM2.5 in the workshop were 20.3 ng/m3 (24.7 μg/g) and 16.1 ng/m3 (115 μg/g), respectively. In practice, the fumes containing gaseous and particulate PBDEs were treated by the combination of alkaline solution absorption and activated carbon adsorption. Compared to PBDE concentration in workshop floor dust (2680 ng/g), PBDE concentrations in solution scum (68,000 ng/g) and hood inside dust (20,200 ng/g) were condensed. The concentrations of ∑6PBDEs at the stack outlet (416 pg/m3) after gas treatment were lower than those in the stack pipe (1310 pg/m3) and hood inside (7440 pg/m3). The PBDEs in fumes were removed through physical adsorption of alkaline solution and activated carbon, and solution scum constituted the main mass discharges of PBDEs. The emission factor of PBDEs at the stack outlet was 47.3 ng ∑6PBDEs/kg WPCB. As a result, the WPCB de-soldering process is an important source of PBDE pollution, and gas treatment of solution absorption and activated carbon adsorption can reduce PBDE emission to some extent.

INFLUENCE OF THERMAL RESISTANCE OF AIR CONDENSER TUBES ON STEAM COOLING EFFICIENCY


 
 
 The research is carried out using a mathematical model of conditions and features of condensation processes with the influence of changes in internal and external thermal resistances of working bodies, which occur during contamination of outside and inside metal pipes of heat exchange surfaces of air condenser. capacitor. Particular attention is paid to the selection, detailing and determination of more than twenty basic parameters that characterize the operation of the direct cooling unit of the condensing unit for the summer, the conditions of heat transfer processes between the working bodies taking into account the finned outer surface of elliptical condenser tubes. The results of experiments on the mathematical model are analyzed and the influence of the incoming air velocity and ambient temperature on the output steam pressure in the condenser direct air cooling system within the change of internal and external thermal resistances in the range 0-0.001(m2·K)/W due to cooling tube contamination is determined. air condenser steam turbine installation. Conditions, character and features of influence of thermal resistance of pollution in cooling tubes on steam pressure at an exit from them are defined, the basic factors defining steam pressure at an exit, necessity of the organization of control of thermal resistance of pollution in a pipe during unit operation at variable operating conditions and expediency is substantiated. conducting test studies of operating modes while taking into account the influence of thermal resistance of external and internal pollution on the thermal efficiency of the cooling unit.
 
 
 
 Studies have shown that at a fixed value of the heat load of the exhaust steam, the pressure of the steam outlet increases with increasing ambient temperature and decreasing the speed of the incoming air.
 
 
 
 
 

Pitting Hole Evaluation by Active Infrared Thermography in Stainless Steel 304

Nowadays, infrared thermography technique is widely use in an engineering study to inspect various types of problem. In this experiment, active infrared thermography method is applied to overcome the constraint locating pitted inside pipe. The main purpose of this experiment is to examine the location of pitted occur in the stainless steel 304 and at the same time to identify the transient effect on the pipe against the duration of time radiation exposed. This experiment uses two unit of spotlight as sources of heat to emit radiation energy to the surface of the pipe. A FLIR T640 thermography camera was used to record the thermal contrast of the pipe in real time using FLIR Tools+ software installs in the laptop. This experiment was tested at normal surrounding temperature. All of the temperature data is then interpreted into contour graph by using Microsoft Excel to see the defect area based on temperature distribution. Based on the result, the most significant temperature drops within highest gradient observed at cooling phase are within 7s, 2s and 1s interval for 10s, 20s and 30s of radiation exposure respectively. The time of the pitted to appear is related to the exposure time of the radiation. The finding of this experiment shows that short duration time of radiation exposure will give the longer time interval of significant gradient to appear. Therefore, this experiment proves that infrared thermography is one of the non- destructive testing methods that can be used in inspecting the pipeline.

Hydromechanical device to clean the inside of pipes from paraffin deposits

Hydromechanical device to clean the inside of pipes from paraffin deposits

Study on Residual Stress Relief Technology Using Phase Transformation in Metal Additive Manufacturing

For the manufacture of plastic molds and die casting molds, metal optical modeling of the PBF system capable of creating a cooling pipe inside is effective, and effects of shortening of the production cycle and improvement of the accuracy are obtained. However, the metal optical modeling of the PBF system has problems of warpage and cracking, and it is difficult to manufacture a shape object in which stress concentration occurs or a large modeled.

Experimental analysis of atmospheric heat sinks as heat dissipators

Overheating, a general problem both in urban spaces and inside buildings, calls for the deployment of passive cooling techniques to reduce energy consumption, protect the environment and institute satisfactory comfort levels. A key factor in such techniques is the capitalisation on the cooling potential of natural heat sinks. The sky, one such sink, has essentially limitless cooling power. In addition, its temperature on fair nights is lower than that of other environmental sinks (ground and air). The sky’s promise in that respect prompted this exploration of the potential of nocturnal radiation cooling. A review of the state of the art revealed that in all the radiative dissipators developed and tested to date the dissipation fluid (water) transferred heat indirectly to the heat sink (the sky) by circulating water inside solar collector pipes. The highest values reported for maximum dissipation power were on the order of 100 W/m2. The present study aimed to asses night time dissipation power in a dual system in which water circulated either inside pipes or flowed down the outer surface of the collector. The two modes, one involving in-pipe circulation and the other outer surface downflow, were compared experimentally, for whereas the former has been analysed and assessed by earlier researchers, the latter has not. The empirical findings verified that downflow setups enhanced cooling, delivering up to five-fold the dissipation power obtained with the conventional arrangement.

Multimodal pipe-climbing robot with origami clutches and soft modular legs

In nature, climbing trees and pipes of varying diameters or even navigating inside of hollow pipes and tree holes is easy for some climbing animals and insects. However, today’s pipe-climbing robots, which are important for automatically conducting periodic inspections and maintenance of pipelines to save time and keep humans away from hazardous environments, are designed mainly for a specific task, limiting their adaptability to different working scenarios and further implementation in real-life. In this paper, we propose a pipe-climbing robot with a soft linear actuator for bioinspired propulsion, two origami clutches to realize multi-degrees-of-freedom (DoF) motion and two pairs of soft modular legs for multimodal climbing. Design, modeling and experimental validation of the origami clutch are introduced in detail. Preliminary experimental results show that we can achieve a stroke of up to 289.6% and a maximum 45° bending angle on the soft linear actuator by regulating the air pressure inside the soft actuator and origami clutches. Additionally, by choosing the leg-type, three climbing modes, including out-pipe versatile mode, out-pipe high-force mode and in-pipe mode can be realized for particular working scenarios. A prototype climbing robot demonstrates that in out-pipe versatile mode, the robot can climb on the exterior of pipes made of various materials including PVC, rubber and metal with diameters ranging from 105 to 117 mm. In the out-pipe high-force mode, the climber can navigate along a specific pipe carrying maximum 675 g external load at the top or 200 g hanging from the bottom, as well as keeping functional without failure under static loads as high as 1968 g. In the in-pipe mode, the robot is able to travel inside pipes. This research might bridge the design gap between in-pipe and out-pipe climbing robots while offering an alternative option for soft robots to execute multi-DoF motion.

ACOUSTIC VIBRATIONS HYDRODYNAMIC EMITTER PARAMETERS DETERMINATION

The processing of fibrous materials with aqueous solutions should preserve the natural properties of the fiber in order to obtain high-quality raw materials for the textile industry. The proposed hydrodynamic emitter is a device consisting of a rectangular housing with a square pipe inside, three conical converging nozzles connected to this pipe with slotted outlet openings. A model of a periodic lattice with a period d is considered, which consists of a finite number of elastic rods of the rectangular cross-section is considered for a theoretical study of a flat hydrodynamic acoustic emitter. It is assumed that the ends of the rods are rigidly fixed, and each rod of the lattice can only perform harmonic elastic bending vibrations. A multifactor experiment was conducted to clarify the design parameters of the converter.

Development of Flow Pattern and Pressure Drop in Gas-liquid Swirl Flow inside Horizontal Pipe

Development of Flow Pattern and Pressure Drop in Gas-liquid Swirl Flow inside Horizontal Pipe

INVESTIGATION OF MULTIPHASE CONDITION IN PIPELINE USING GAMMA COMPUTED TOMOGRAPHY

INVESTIGATION OF MULTIPHASE CONDITION IN PIPELINE USING GAMMA COMPUTED TOMOGRAPHY. Deposition of sand particles in pipeline is a problem that often occurs in the production and distribution of oil and gas. It could cause increased preasure, equipment failure, pipeline erosion, and production decline. It is very necessary to investigate inside condition of the pipeline without interrupting the operation. Gamma computed tomography (CT) is a technique that can image the internal structure of an object without interrupting or damaging the object (non-destructive testing). This paper presents a preliminary experimental study of multiphase (solid, liquid, and gaseous) condition inside a horizontal pipe using gamma CT technique. A collimated Cs-137 source with 3.7 GBq activity emited gamma photons to penetrate a 14 inches diameter horizontal pipe containing sand, water, and gasoline. The photons that penetrated object were detected using a scintillation detector at the other side of object. The scanner system performed translation and rotation scans to get 64 projection data which will then be reconstructed into an image. The reconstructed images were able to show the pipe wall and the condition of the inside of pipe which was filled with sand, water, and gasoline. The pixel value is linear to material density with R 2 = 0.9543. The result indicated the potential of gamma CT as the suitable technique to be used to investigate the multiphase conditions in pipeline .

Verification and Evaluation of Robotic Inspection of the Inside of Culvert Pipes

Public infrastructures, such as tunnels and bridges, are important for our daily life and their increased deterioration causes concern. Culvert pipes are installed underground below roads, and their damage has an impact on the function and integrity of infrastructures. However, culvert pipes in closed and confined spaces are difficult to inspect, and their conditions are generally not evaluated. In this paper, we describe the findings of field experiments involving the inspection of the inside of culvert pipes via robotic systems.