Heat pipes, as passive elements show a high level of reliability when taking heat away and they can take away heat flows having a significantly higher density than systems with forced convection. A heat pipe is a hermetically closed duct, filled with working fluid. Transport of heat in heat pipes is procured by the change of state of the working fluid from liquid state to steam and vice versa and depends on the hydrodynamic and heat processes in the pipe. This study have been focused on observing the impact these processes have on the heat process, the transport of heat within the heat pipe with the help of thermovision. The experiment is oriented at scanning the changes in the surface temperatures of the basic structural types of capillary heat pipes in vertical position.

This paper presents the results of research regarding measurements of the values of pressure drops during horizontal flow of gas-liquid and gas-liquid-liquid mixture through 180o pipe bends. The conducted insightful analysis and assessment during multi-phase flow in pipe bends has enabled to develop a new method for determination of their values. This new method for determining pressure drops ensures higher precision of calculation in comparison to other methods presented in literature and can be applied for calculation of these parameters during multi-phase flows in pipe bends with various geometries.

For most precious metal mines, cemented tailings backfill slurry (CTBS) with different cement-sand

ratio and solid concentration are transported into the gobs to keep the stability of the stope and mitigate

environmental pollution by mine tailing. However, transporting several kinds of CTBS through the same

pipeline will increase the risk of pipe plugging. Therefore, the joint impacts of cement-sand ratio and

solid concentration on the rheological characteristics of CTBS need a more in-depth study. Based on the

experiments of physical and mechanical parameters of fresh slurry, the loss of pumping pressure while

transporting CTBS with different cement-sand ratio, flux and solid mass concentration were measured

using pumping looping pipe experiments to investigate the joint impacts of cement-sand ratio and solid

concentration on the rheological characteristics of CTBS. Meanwhile, the effect of different stopped pumping

time on blockage accident was revealed and discussed by the restarting pumping experiments. Furthermore,

Fluent software was applied to calculate the pressure loss and velocity distribution in the pipeline to further

analysis experimental results. The overall trends of the simulation results were good agreement with the

experiment results. Then, the numerical model of the pipeline in the Sanshandao gold mine was conducted

to simulate the characteristics of CTBS pipeline transportation. The results show that the pumping pressure

of the delivery pump can meet the transportation requirements when there is no blockage accident. This

can provide a theoretical method for the parameters optimizing in the pipeline transportation system.

In this Paper, a parametric study on pipes buried in soil was performed illustrating the results of blast loading. Effects of various parameters such as the physical properties of water, oil, gas, air, soil, pipes, and TNT have been investigated. The arbitrary Lagrangian-Eulerian (ALE) method was employed using LS-DYNA software. The maximum pressure in a buried pipe explosive was observed at an angle of about 0° to 45° and the minimum pressure occurred at an angle of about 45° to 90°. Therefore, all figures in this study illustrate that fluid pressure levels in buried pipes can help in their stabilization. In generally, by increasing the 1.23 times of liquid density under the explosion, the pressure levels in the soil decreased by 1.3 percent. The gas pressure has been increasing more than oil and water pipes 39.73 and 40.52 percent, respectively.

The production of thermal energy from solar energy by flat collectors finds nowadays many applications due to their innumerable economic and environmental interests. Currently, conservation of energy resources has become a global priority. On the other hand, given the dizzying demand for energy, has led specialists to find new techniques, such as renewable energies (solar, wind and geothermal). The present work is a contribution, by numerical simulation, to the study of heat transfer in flat solar collectors. On the basis of some experimental data, several simulation calculations have been carried out in order to determine the influencing parameters allowing better performance of the sensors and ensuring a good homogeneity of the temperature distributions. Based on the observation that, due to the low thermophysical properties of the air used as heat transfer fluid, solar air collectors rather give poor yields. It has been found very useful to have ‘baffling’ obstacles of various shapes and forms in the solar collector duct. This increases the thermal transfer of a coolant, which clearly improves the thermal efficiency of the solar air collector. This article consists mainly of studying the effects on heat transfer of turbulent forced convection by baffles of zigzag shapes, placed in a rectangular channel, using the finite volume method. The pressure-velocity coupling has been processed by the SIMPLEC algorithm. The results are presented in terms of the average Nusselt number and temperature field for different positions.

In the paper presented are studies on the investigation of the capillary forces effect induced in the porous structure of a loop heat pipe using water and ethanol ad test fluids. The potential application of such effect is for example in the evaporator of the domestic micro-CHP unit, where the reduction of pumping power could be obtained. Preliminary analysis of the results indicates water as having the best potential for developing the capillary effect.

This paper presents a new welding quality evaluation approach depending on the analysis

by the fuzzy logic and controlling the process capability of the friction stir welding of

pipes (FSWoP). This technique has been applied in an experimental work developed by

alternating the FSW of pipes process major parameters: rotation speed, pipe wall thickness

and travel speed. variable samples were friction stir welded of pipes using from 485 to 1800

rpm, 4–10 mm/min and 2–4 mm for the rotation speed, the travel speed, and the pipe wall

thickness respectively. DMAIC methodology (Defining, Measuring, Analyzing, Improving,

Control) has been used as an approach to analyze the FSW of pipes, it depends on the

attachment potency and technical commonplace demand of the FSW of pipes process.

The analysis controlled the Al 6061 friction stir welded joints’ tensile strength. To obtain

the best tensile strength, the study determined the optimum values for the parameters from

the corresponding range.

This paper presents a design of a tracked in-pipe inspection mobile robot with an adaptive drive positioning system. The robot is intended to operate in circular and rectangular pipes and ducts, oriented horizontally and vertically. The paper covers a design process of a virtual prototype, focusing on track adaptation to work environment. A mathematical description of a kinematic model of the robot is presented. Operation of the prototype in pipes with a cross-section greater than 210 mm is described. Laboratory tests that validate the design and enable determination of energy consumption of the robot are presented.

The performance of ten wickless heat pipes without adiabatic sections is investigated experimentally at low heat inputs 120 to 2000 W/m2 for use in solar water heaters. Three heat pipe diameter groups were tested, namely 16, 22, and 28.5 mm. Each group had evaporator lengths of 1150, 1300, and 1550 mm, respectively, with an extra evaporator length of 1800 mm added to the second group. The condenser section length of all heat pipes was 200 mm. Ethanol, methanol, and acetone were utilized as working fluids, at inventory of 25%, 50%, 70%, and 90% by evaporator volume respectively. The 22 mm diameter pipes were tested at inclination angles 30◦, 45◦, and 60◦. Other diameter groups were tested at 45◦ only. Experiments revealed increased surface temperatures and heat transfer coefficients with increased pipe diameter and evaporator length, and that increased working fluid inventory caused pronounced reduction in evaporator surface temperature accompanied by improved heat transfer coefficient to reach maximum values at 50% inventory for the selected fluids. Violent noisy shocks were observed with 70% and 90% inventories with the tested heat pipes and the selected working fluids with heat flux inputs from 320–1900 W/m2. These shocks significantly affected the heat pipes heat transfer capability and operation stability. Experiments revealed a 45◦ and 50% optimum inclination angle of fill charge ratio respectively, and that wickless heat pipes can be satisfactorily used in solar applications. The effect of evaporator length and heat pipe diameter on the performance was included in data correlations.

The aim of this paper is twofold: to estimate the unsteady pressure-flow variations in gas transmission pipelines using the ensemblebased data assimilation approach and to analyse the strength of steel tubes reinforced with composite sleeves containing localized part-wall thickness loss caused by corrosion while taking into consideration a safe operating pressure of the pipeline. For a steel thin-walled cylinder containing a partwall metal loss, a flexible wrap of fibreglass as well as carbon glass with epoxy resin are determined. The strength of the repaired pipeline with two kinds of materials for sleeves is investigated taking into consideration the internal pressure at the defect location. For the case study, a section of the Yamal transit pipeline on the Polish territory is selected. The results enable pipeline operators to evaluate the strength of corroded steel pipelines and develop optimal repair activities, which are of vital importance for the maintenance and operation of underground steel networks.

A new expression is proposed to calculate the earth-energy of an earth-air-pipe heat exchanger during winter heating for three kinds of soil in France. An analytical model is obtained by using numerical computation developed in Scilab – a free open source software. The authors showed the comparison between their simple analytical model and experimental results. They showed the influence of different parameters to specify the size of the heat exchanger.

The airflow through a two-dimensional horizontal rectangular cross-section channel in the presence of two baffles has been numerically examined and analyzed in the steady turbulent regime. The baffles were of the zig-zag type or plane one. The calculations are based on the finite volume approach and the average Navier–Stokes equations along with the energy equation, have been solved using the SIMPLE algorithm. The nonuniform structured quadrilateral-type element mesh is used in this study. The fluid flow patterns represented for Reynolds numbers based on the hydraulic diameter of the channel ranging from 5000 to 20 000. Effects of various Reynolds number values on flow fields, dimensionless axial velocity profiles, as well as local and average friction coefficients in the test channel is presented. The obtained results show that the flow structure is characterized by strong deformations and large recirculation regions. In general, the fluid velocity and skin friction loss rise with the increase in the flow rate and hence the Reynolds number.

The airflow in the mouth of an open and closed flue organ pipe of corresponding geometrical proportions is studied. The phase locked particle image velocimetry with subsequent analysis by the biorthogonal decomposition is employed in order to compare the flow mechanisms and related features. The most significant differences lie in the mean velocity distribution and rapidity of the jet lateral motion. Remarks on the pressure estimation from PIV data and its importance for the aeroacoustic source terms are made and a specific example is discussed.

Wave motion in pipe bends is much more complicated than that in straight pipes, thereby changing considerably the propagation characteristics of guided waves in pipes with bends. Therefore, a better understanding of how guided waves propagate in pipe bends is essential for inspecting pipelines with bends. The interaction between a pipe bend and the most used non-dispersive torsional mode at low frequency in a small-bore pipe is studied in this paper. Experiments are conducted on a magnetostrictive system, and it is observed that T(0,1) bend reflections and mode conversions from T(0,1) to F(1,1) and F(2,1) occur in the pipe bend. The magnitude of the T(0,1) bend reflections increases with increasing propagation distance and excitation frequency. The amplitude of the mode-converted signals also increases with increasing propagation distance, but it decreases with increasing excitation frequency. Because of their longer bent path, the test signals for a pipe bend with a bending angle of 180X are much more complicated than those for one with a bending angle of 90X. Therefore, it is even more difficult to scan a bent pipe with a large bending angle. The present findings provide some insights into how guided waves behave in pipe bends, and they generalize the application of guided-wave inspection in pipelines.