Dynamic modelling of heat transfer in thermal-acoustic fatigue tests

2017 ◽  
Vol 71 ◽  
pp. 675-684 ◽  
Author(s):  
Wenjun Yu ◽  
Xiaofei Wang ◽  
Xun Huang
Keyword(s):  
Heat Transfer ◽  
Dynamic Modelling ◽  
Fatigue Tests ◽  
Acoustic Fatigue

Limitations of Corrosion Resistant Alloy in High CO2 Gas Production Systems: A Case Study

2021 ◽  
Author(s):  
Jorge Rodriguez ◽  
Susana Gómez ◽  
Ngoc Tran Dinh ◽  
Giovanni Ortuño ◽  
Narendra Borole
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
High Pressure ◽  
Stainless Steel ◽  
Carbon Steel ◽  
Material Selection ◽  
Dynamic Modelling ◽  
General Corrosion ◽  
High Co2

Abstract The paper presents the application of a holistic approach to corrosion prediction that overcomes classical pitfalls in corrosion testing and modelling at high pressure, high temperature and high CO2 conditions. Thermodynamic modelling of field and lab conditions allows for more accurate predictions by a novel CO2/H2S general corrosion model validated by laboratory tests. In the proposed workflow, autoclave tests at high pressure and temperature are designed after modeling corrosion in a rigorous thermodynamic framework including fluid-dynamic modelling; the modeled steps include preparation, gas loading and heating of fluid samples at high CO2 concentration, and high flow velocities. An autoclave setup is proposed and validated to simultaneously test different conditions. Corrosion rates are extrapolated to compute service life of the materials and guide material selection. The results from the model and tests extend the application of selected stainless steel grade beyond the threshold conditions calculated by simplistic models and guidelines. Consideration of fugacities and true aqueous compositions allows for accurate thermodynamic representation of field conditions. Computation by rigorous fluid dynamics of shear stress, multiphase flow and heat transfer effects inside completion geometry lead to a proper interpretation of corrosion mechanisms and models to apply. In the case study used to showcase the workflow, conventional stainless steel is validated for most of the tubing. It is observed that some sections of the system in static condition are not exposed to liquid water, allowing for safe use of carbon steel, while as for other critical parts, more noble materials are deemed necessary. Harsh environments pose a challenge to the application of conventional steel materials. The workflow applied to the case study allows accurate representation and application of materials in its application limit region, allowing for safe use of carbon steel or less noble stainless steels in those areas of the completion where corrosion is limited by multiphase fluid-dynamics, heat transfer or the both. The approximation is validated for real case study under high CO2 content, and is considered also valid in the transportation of higher amounts of CO2, for example, in CCUS activities.

Fatigue Testing of Polymeric Hollow Fibre Heat Transfer Surfaces by Pulsating Pressure Loads

2016 ◽  
Vol 821 ◽  
pp. 3-9 ◽  
Author(s):  
Tereza Brožová ◽  
Tomáš Luks ◽  
Ilya Astrouski ◽  
Miroslav Raudenský
Keyword(s):  
Heat Transfer ◽  
Fatigue Testing ◽  
Fatigue Loading ◽  
Hollow Fibre ◽  
Fatigue Tests ◽  
Outer Diameter ◽  
Hollow Fibres ◽  
Different Temperatures ◽  
Hot Bath ◽  
Number Of Cycles

This article deals with fatigue tests of polymeric hollow fibre heat transfer surfaces. The hollow fibres have an outer diameter between 0.5-0.8 mm and wall thickness 10 % of the outer diameter. These plastic heat transfer surfaces have some limitations but also many benefits. One of the limitations is the durability of plastic under fatigue loading. The heat transfer surfaces were subjected to pulsating pressure loads under different conditions (level of pressure, ambient temperature, number of cycles). Firstly, only an internal hydraulic pulsating load was applied and the behaviour of the hollow fibres was observed, focusing especially on the presence of leaks, ruptures, etc.Then, other conditions of operations were added. The heat transfer surfaces were immersed in a hot bath and loaded by internal pulsating pressure and high temperature simultaneously. Testing under different temperatures is important because the temperature significantly affects the material properties. The presence of leaks, ruptures and other possible damage was monitored as with previous tests.

Step-transient method for measurement of the heat transfer coefficient at surfaces exposed to simulated building outdoor environments using the sol-air thermometer

2018 ◽  
Vol 42 (3) ◽  
pp. 373-387
Author(s):  
KE Anders Ohlsson ◽  
Ronny Östin ◽  
Thomas Olofsson
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Dynamic Modelling ◽  
Transient Method ◽  
Insulation Layer ◽  
Exterior Surface ◽  
Steady State Method ◽  
Outdoor Environments ◽  
The Heat Transfer Coefficient

The environmental boundary conditions of the building exterior surface could be expressed in terms of the sol-air temperature To and the heat transfer coefficient ho. This has previously been derived by applying Thevenin’s theorem to the linear thermal network model of the convective and radiative environment. Here, the sol-air thermometer, previously used only for measurement of To, was applied for accurate measurement of ho. The step-transient method was used, where the temperature of the sol-air thermometer was initially raised to above To and then monitored during its transient return to thermal equilibrium. This method was validated by (1) comparison of ho results against values obtained with a steady-state method and (2) comparison of predicted heat flux against the electrical heater power, supplied for validation purpose. Accurate results were obtained, with 7.3% measurement uncertainty. The present sol-air thermometer time constant τ was around 1 h. Based on predictions from dynamic modelling, the τ could be reduced 10-fold, with only small effects on the accuracy from heat loss through the insulation layer.

scholarly journals Implementation of a cooling system to develop experimental fatigue tests below zero grades Celsius

2020 ◽  
Vol 25 (4) ◽  
pp. 519-525
Author(s):  
Carlos Gerardo Cárdenas Arias ◽  
Camilo Leonardo Sandoval Rodríguez ◽  
Arly Darío Rincón Quintero ◽  
Pablo David Díaz Melo
Keyword(s):  
Heat Transfer ◽  
Fatigue Test ◽  
Fatigue Failure ◽  
Low Temperatures ◽  
Initial Temperature ◽  
Cooling System ◽  
Fatigue Tests ◽  
Sample Material ◽  
Industrial Level ◽  
Materials Behavior

Temperature is one of the matter properties with the greatest influence on the materials behavior existing in nature and those man designed. This physical magnitude allows to demonstrate and define behaviors and materials characteristics in the industry in general. Its influence is present in all the places where the materials fulfill functions, however, in some applications its influence is very little, which allows to disregard its effects. In the steels case (one of the most used materials at the industrial level today), the temperature variation produces dilation or contraction, depending on the temperature magnitude and its variation that affects them. Temperature increases generate an expansion phenomenon in the materials, which under load will reach a point where they present thermal fatigue failure. The opposite is that of temperature drops, where the phenomenon that occurs is contraction, often leading to the loss of adjustments and interference that compromise the equipment functionality and integrity. The fatigue failure mentioned is presented as a result of the stresses and deformations present in both cases. It is desired to condition a rotational flex fatigue test equipment with a cooling system to bring the sample material to temperatures below zero degrees Celsius, in order to check how low temperatures, affect the resistance of steel to fatigue. For this, a cooling system was designed and the fatigue equipment was adapted to reduce heat transfer. After carrying out this implementation and determining that the sizes of the devices were suitable for the proposed purposes, the initial temperature tests were carried out and, once this part was achieved, three repetitions of a rotary fatigue test were performed that demonstrated that the equipment can operate normally.

Thermal Fatigue Properties of the Fin in the Boilers

2007 ◽  
Vol 353-358 ◽  
pp. 315-318 ◽  
Author(s):  
Yukihiro Tokunaga ◽  
Nu Yan ◽  
Daisuke Yonekura ◽  
Riichi Murakami
Keyword(s):  
Heat Transfer ◽  
Fatigue Test ◽  
Thermal Fatigue ◽  
Fatigue Cracks ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Test Machine ◽  
Element Analysis ◽  
Heat Transfer Efficiency ◽  
Heating And Cooling

In order to improve the heat transfer efficiency, the fins are commonly used in the industrial boiler in Japan. In actual application, the thermal fatigue due to the cyclic change of temperature usually occurs in the fins. The thermal fatigue tests were carried out by using the thermal fatigue apparatus designed. The designed testing apparatus can apply thermal load to the fin by giving heating and cooling alternatively. The fatigue cracks can be observed in the vicinity of the toe in the thermal fatigue test. The heat transfer coefficient and the thermal stress were calculated by using Finite Element Analysis (FEA) method. The fatigue experiments of the fins were also conducted using electro-hydraulic servo fatigue test machine in the laboratory. The results of thermal fatigue experiments were discussed by comparing with those of the mechanical fatigue experiments.

scholarly journals Development of an Efficient Modelling Approach for Fin-Type Heat-Exchangers in Self-Recuperative Burners

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6873
Author(s):  
Nicolas Dinsing ◽  
Nico Schmitz ◽  
Christian Schubert ◽  
Herbert Pfeifer
Keyword(s):  
Heat Transfer ◽  
Cfd Simulation ◽  
Dynamic Modelling ◽  
Mesh Size ◽  
Simulation Models ◽  
Radiant Tube ◽  
Common Solution ◽  
Efficient Combustion ◽  
Detailed Simulation ◽  
Modelling Approach

Self-recuperative burners are a common solution for efficient combustion systems in industrial furnaces. Due to the geometric complexity of the recuperators, a detailed CFD simulation is computationally expensive and not feasible for simulation models of burner-integrated systems such as radiant tubes. Especially in the FSI studies of radiant tubes, the temperature of the radiant tube surrounding the burner is decisive for the final results. The exclusion of the recuperator from the simulation models introduces significant uncertainties in the simulations results. The presented paper describes an innovative, efficient approach to model a fin-type recuperator in which the recuperator is geometrically reduced. The resulting acceleration of the numerical simulation makes a fully dynamic modelling of the recuperator in a radiant tube simulation possible. Specifically designed source terms are used to model pressure loss and heat transfer inside the recuperator to match results obtained with a detailed simulation model. The results show deviations in total heat transfer of less than 1.3% with a 98.5% reduction of numerical mesh size. The computational savings enable comprehensive modelling of air preheat for radiant tube simulations and accurately replicate flow and temperature profiles in the recuperator.

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