Heat Pipelines Research Articles

Study of the Influence of Electromagnetic Fields on the Corrosion of District Heating Pipelines

One of the primary indicators influencing the dependability of the district heating system system is the corrosion of the pipeline surface. This article presents the findings of measurements and tests conducted on the example of the heat supply system in our country. The effects of electromagnetic fields on the surface corrosion of heat pipelines located in the area intersecting with high voltage lines and along overhead power lines are discussed. In the contemporary era, ecological concerns, including those pertaining to electromagnetic ecology, have emerged as a significant area of focus within the domains of science, technology, and socioeconomics. The study of the impact of energy pollution factors has led to the development of electromagnetic safety norms and standards. However, at the current stage, there is a lack of unified norms and standards for electromagnetic ecological assessment. Results of measurements indicate that the electric field strength is 0.38-32.33 V/m, while the magnetic field strength is 0.07-11.56 A/m. The voltage of the electric field is directly proportional to the voltage of the conductor. At the measurement point near the overhead power line (at a height of 1 m above the heat transmission line), the maximum voltage was 32.33 V/m. However, since the voltage of the magnetic field is directly proportional to the current running through the electric conductor, the current flowing through the conductor on the output of the extension generator had the highest value, resulting in the maximum magnetic field voltage of 11.56 A/m, which indicates that the measurement is accurate.

Study of the Influence of Electromagnetic Fields on the Corrosion of District Heating Pipelines

One of the primary indicators influencing the dependability of the district heating system system is the corrosion of the pipeline surface. This article presents the findings of measurements and tests conducted on the example of the heat supply system in our country. The effects of electromagnetic fields on the surface corrosion of heat pipelines located in the area intersecting with high voltage lines and along overhead power lines are discussed. In the contemporary era, ecological concerns, including those about electromagnetic ecology, have emerged as a significant area of focus within science, technology, and socioeconomics. The study of the impact of energy pollution factors has led to the development of electromagnetic safety norms and standards. However, there is a lack of unified norms and standards for electromagnetic ecological assessment at the current stage. The measurements indicate that the electric field strength is 0.38-32.33 V/m, while the magnetic field strength is 0.07-11.56 A/m. The voltage of the electric field is directly proportional to the voltage of the conductor. At the measurement point near the overhead power line (at a height of 1 m above the heat transmission line), the maximum voltage was 32.33 V/m. However, since the voltage of the magnetic field is directly proportional to the current running through the electric conductor, the current flowing through the conductor on the output of the extension generator had the highest value, resulting in the maximum magnetic field voltage of 11.56 A/m, which indicates that the measurement is accurate.

Numerical Simulation Study on Reverse Source Tracing for Heating Pipeline Network Leaks Based on Adjoint Equations

In order to identify the leak source in complex heating pipeline networks, a timely and effective simulation of the leakage process was conducted. The open-source computational fluid dynamics software OpenFOAM 5.0 was combined with the PISO algorithm to simulate the pressure during the leakage in water supply networks, transforming the reverse source tracing problem into the solution of an adjoint equation. The validation of the transient adjoint equation for single-phase flow was completed through simulation, and the pressure wave change graph at the moment of the network leakage was solved, which was consistent with the experimental results. Using the open-source finite element analysis software OpenFOAM 5.0, the positioning accuracy of pipeline leak points can be controlled within the range from 92% to 96%. Based on the pressure wave change graph, the position of the leak source in the complex network was determined using the reverse source tracing method combined with the second correlation theory. The results show that the calculation speed of the PISO algorithm combined with the adjoint equation is significantly better than that of the individual SIMPLE and PISO algorithms, thereby proving the superiority of the adjoint method.

Corrosion-mechanical state of the heat pipeline after long-term operation

Corrosion-mechanical state of the heat pipeline after long-term operation

Особливості і розвиток технологій виявлення витоків трубопроводів тепло- та водопостачання в умовах зношеності та мілітарних впливів

The article is dedicated to analyzing the current state of underground heat and water supply pipelines in Ukraine, particularly under conditions of significant wear and tear and military impacts. The challenges associated with the operational detection of hidden leaks are exami¬ned, as well as the capabilities of known methods for identifying damaged sections and leak locations. The development of acoustic and correlation leak detectors is discussed as a promi¬sing direction for improving pipeline diagnostics in war conditions and amid network dete¬rioration. Several innovations are proposed, including a new parametric correlation method, spatial-frequency selection of useful leak signals, and other advancements to enhance the diag¬nostics of critical infrastructure. These measures aim to improve the effectiveness of leak de¬tection, ensure the continuity of essential services, and strengthen the resilience of the energy system in the face of current challenges.

Numerical study on drag reduction and heat collection efficiency of oil based on solar concentrating system

Traditional onshore crude oil storage and transportation consumes a lot of energy. In this paper, a concentrating type of high-temperature crude oil transportation pipeline heating system is proposed, which uses concentrators to collect and focus sunlight on the pipeline. The high-temperature oil flows through the heat exchanger at the end of the pipeline, where it exchanges heat with water to store and recover heat for utilization in the heat collector. The temperature rise is significant and the uniformity improves as oil extends through the pipeline under various multiples of solar radiation achieved with concentrators. The inlet rate of oil is a negative factor affecting the outlet temperature. Compared to non-concentrated light, the friction coefficient and viscosity of oil are reduced, resulting in a more effective drag reduction effect. To validate the accuracy of simulation results and compare them with theoretical calculations, ensuring that the margin of error is within 8.5%. The type of concentrators, laying distance of the concentrators below the pipeline, concentration ratio (CR), and the inlet rate can be adjusted based on climatic conditions and required oil temperature. This paper is of great significance for reducing energy consumption in long-distance oil transportation and realizing the energy transition.

DEVELOPMENT PROCESS OF A FREQUENCY CONVERTER FOR INDUCTION HEATING OF OIL PIPELINE

The article provides a detailed overview of the history, development and applications of frequency converters, with particular emphasis on their use in the oil and gas industry. It traces the evolution of frequency converters from their inception in the late 19th and early 20th centuries to their modern applications, which use microprocessors and digital signal processing to precisely control the output frequency. In the oil and gas industry, frequency converters are critical to efficient and accurate induction heating of pipelines. They convert a fixed frequency and voltage power supply into a variable frequency and variable voltage output, controlling the speed of the induction motors used in the heating process. The article also covers the design and modeling of frequency converters, discussing the process of characterizing them, creating mathematical models, and using modeling software tools such as MatLab. It presents equations for inductive energy, capacitor energy, resonance conditions and power factor, which are necessary in the mathematical modeling of frequency converters. The article concludes by highlighting the impact of frequency converters on the efficiency and economics of induction heating systems. It emphasizes the need for careful design and modeling to ensure optimal performance and safety.

A novel mathematical model for modeling viscosity and temperature relationship for dead oils

Viscosity is crucial in subsurface and surface transport, used in engineering domains like heat transfer and pipeline design. However, measurements are limited, necessitating predictive viscosity relationships. Existing models lack precision or pertain to limited fluids, and accurately forecasting dead oil viscosity remains challenging due to errors. The study presents a mathematical algorithm to accurately estimate viscosity values in hydrocarbon fluids. It uses a robust non-linear regression technique to establish a reliable relationship between fluid viscosity and temperature within a specific temperature range. The algorithm is applied to extra-heavy to light crude oil samples from Iranian oilfields, revealing viscosity values ranging from 0.29 cp to 5328.74 cp within a dataset of 243 viscosity data points. After modeling each of these five fluids, the highest values obtained for the maximum absolute error and relative error are related to the fluid with an API gravity of 12.92. The maximum absolute error and relative error for this fluid sample are 1.25 cp and 6.04%, respectively. The algorithm offers acceptable precision in outcome models, even with limited training data, demonstrating its effectiveness in training models with less than 30% of available data. Moreover, these models end up with a near-unity coefficient of determination in testing data, reaffirming their proficiency at reflecting empirical data with remarkable accuracy.

Evaluation of Electrochemical Properties and Life Prediction of Sensor Wire in Leak Detection Systems of Underground Heating Pipelines

In this study, we investigated the electrochemical properties and lifespan of the NiCr (NiCr 8020) sensor wire of a resistance leaking detection (LD) system to detect pipe corrosion and leakage in an actual district heating (DH) system. The temperature and applied stress of the sensor wire during the actual operation of the resistance LD system of the DH system were derived through simulations and calculations. The anodic dissolution of the sensor wire was accelerated with the increased temperature and the applied current. The corrosion type changed from localized corrosion, such as pitting, to uniform corrosion. The applied stress caused ductile fracture of the thinned sensor wire by anodic dissolution. In conclusion, we confirmed that in the resistance LD system of a DH system, where current and stress are applied at high temperatures, the sensor wire becomes thin due to the anodic dissolution and subsequent ductile fracture. In addition, the lifespan of the sensor wire was derived according to the resistance level measured in the resistance LD system of the DH system. Our findings contribute to preventing failure and improving the reliability of the resistance LD systems of DH systems.

Simulation Analysis of Loss of Coolant Accidents Based on CNIFA Program

Abstract The loss of coolant accident in the primary pipeline of a reactor is a typical accident in the safety analysis of nuclear power plants, and it is one of the accidents with a high probability of occurrence. Due to the extremely complex structure of the lower space of the containment vessel, it increases the complexity of fluid flow during a loss of coolant accident. This article is based on the internal water flooding analysis simulation software CNIFA of a nuclear power plant to simulate the water flooding of a rupture in the main pipeline heat pipe section of a power plant, and to conduct a comprehensive water flooding scenario simulation for this working condition. The quantitative information collected during the simulation process, including dynamically displayed water volume, water level, and their changes over time, facilitate emergency response personnel to choose the correct response plan in advance, it can also provide more accurate basis for various specialties in design analysis.

A non-invasive pipeline heat flux measurement method and application based on CFBG

A non-invasive pipeline heat flux measurement method and application based on CFBG

Analysis of operation regulation on delay time in long-distance heating pipe systems for practical engineering

Analysis of operation regulation on delay time in long-distance heating pipe systems for practical engineering

Flow assurance of waxy crude oil through thermal methods using nichrome wire and ultrasonic waves effects – Experimental investigation

Flow assurance of waxy crude oil through thermal methods using nichrome wire and ultrasonic waves effects – Experimental investigation

Hybrid-timescale optimal dispatch strategy for electricity and heat integrated energy system considering integrated demand response

Hybrid-timescale optimal dispatch strategy for electricity and heat integrated energy system considering integrated demand response

Soil Marginal Effect and LSTM Model in Chinese Solar Greenhouse.

The food crisis has increased demand for agricultural resources due to various factors such as extreme weather, energy crises, and conflicts. A solar greenhouse enables counter-seasonal winter cultivation due to its thermal insulation, thus alleviating the food crisis. The root temperature is of critical importance, although the mechanism of soil thermal environment change remains uncertain. This paper presents a comprehensive study of the soil thermal environment of a solar greenhouse in Jinzhong City, Shanxi Province, employing a variety of analytical techniques, including theoretical, experimental, and numerical simulation, and deep learning modelling. The results of this study demonstrate the following: During the overwintering period, the thermal environment of the solar greenhouse floor was divided into a low-temperature zone, a constant-temperature zone, and a high-temperature zone; the distance between the low-temperature boundary and the southern foot was 2.6 m. The lowest temperature in the low-temperature zone was 11.06 °C and the highest was 19.05 °C. The floor in the low-temperature zone had to be heated; the lowest value of the constant-temperature zone was 18.29 °C, without heating. The minimum distance between the area of high temperature and the southern foot of the solar greenhouse was 8 m and the lowest temperature reading was 19.29 °C. The indoor soil temperature tended to stabilise at a depth of 45 cm, and the lowest temperature reading at a horizontal distance of 1400 mm from the south foot was 19.5 °C. The Fluent and LSTM models fitted well and the models can be used to help control soil temperature during overwintering in extreme climates. The research can provide theoretical and data support for the crop areas and the heating of pipelines in the solar greenhouse.

Fabrication of ultra-precise flexible electrothermal film by direct-write printing porous graphene-Ag structure

Fabrication of ultra-precise flexible electrothermal film by direct-write printing porous graphene-Ag structure

Simulation of Coupled Hydraulic–Thermal Characteristics for Energy-Saving Control of Steam Heating Pipeline

Simulation of Coupled Hydraulic–Thermal Characteristics for Energy-Saving Control of Steam Heating Pipeline

Energy and reserve procurement in integrated electricity and heating system: A high-dimensional covariance matrix approach based on stochastic differential equations

Energy and reserve procurement in integrated electricity and heating system: A high-dimensional covariance matrix approach based on stochastic differential equations

DETECTION OF DISTRICT HEATING PIPELINE USING UAVMOUNTED THERMAL CAMERA AND GPR SCANNING

<p>In this paper the benefits of integration of UAV-mounted (Unmanned Aerial Vehicle) thermal camera and GPR (Ground Penetrating Radar) are analysed. As an example we analized a district heating pipeline in a part of university campus in Novi Sad. Thermal camera mounted on UAV enables fast mapping of routes. These data are then used to detect critical zones where leaking or some other problem occurs and to validate utility cadastral data. Detailed inspection of zones is done using GPR scanning. This provides data such as geometry, precise location of damage, etc. In the last section of the paper advantages of non-invasive detection of district heat line combining active and passive sensors with UAV are explained.</p>

Optimized design of large-diameter directly buried heating pipe

Abstract The elbow of a large-diameter directly buried hot water heating pipeline is the weak part of the whole pipe system. The foam cushion is often used to reduce the stress on the elbow. However, the foam cushion raises the temperature on the outer protective pipe’s surface, which may trigger thermal stress damage to the pipes. In this paper, the insulating pipe at the elbow section is designed with a variable diameter. The numerical simulation of the thermal stress for the outer protective pipe and the working pipe was conducted. The maximum stress for the outer protective pipe is about 3 MPa, and the average stress for the working pipe is 83 MPa, much smaller than the yield stress. Combined with the simulation results, the design ensures the reliability of the elbow and provides a reference for the design of large-diameter and high-temperature heat transfer pipelines.