Optimization of heat transfer in a grooved pipe model by Stochastic Algorithms and DOE based RSM

In the literature, it is proved that grooved pipe models are thermally more efficient than the smooth pipe model. Different than the previous studies in which the groove dimensions are constant along the pipe, we study the effect of groove radius and the gap between adjacent grooves on the local heat transfer coefficients using computational fluid dynamics software. The grooved section consists of three sub-sections to see the effects of groove dimension in stream-wise flow direction. We vary the radius of circular grooves parametrically in each section to optimize the local groove radius throughout the pipe. We couple the fluid flow (1200<Re<24000) with energy equations, and the grooved sections are set as heated wall at constant temperature of 350 K. The optimal mesh has been selected by performing mesh independence study and finer mesh has been used in heated wall section. The radii of grooves are varied from 2 to 6 mm with an increment of 0.2 mm considering the manufacturability of the pipe, to do so we use the design of experiments (DOE). All DOE tools in ANSYS software are examined and compared with full factorial results. After DOE process, local heat transfer coefficient values of all groove parts are examined by response surface methodology (RSM).

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Numerical Analysis of Unsteady Conjugate Heat Transfer and Thermal Stress for a PWR Pressurizer Surge Line Pipe Subjected to Thermal Stratification

Thermal Hydraulic Problems, Sloshing Phenomena, and Extreme Loads on Structures ◽

10.1115/pvp2002-1137 ◽

2002 ◽

Cited By ~ 1

Author(s):

Jong Chull Jo ◽

Young Hwan Choi ◽

Seok Ki Choi

Keyword(s):

Heat Transfer ◽

Thermal Stress ◽

Numerical Analysis ◽

Thermal Stratification ◽

Conjugate Heat Transfer ◽

Heat Transfer Analysis ◽

Stress Distributions ◽

Line Pipe ◽

Pipe Model ◽

Surge Line

This paper addresses three-dimensional numerical analyses of the unsteady conjugate heat transfer and thermal stress for a PWR pressurizer surge line pipe with a finite wall thickness, subjected to internally thermal stratification. A primary emphasis of the present study is placed on the investigation of the effects of surge flow direction on the determinations of the transient temperature and thermal stress distributions in the pipe wall. In the present numerical analysis, the thermally stratified flows (in-surge flow and out-surge flow) in the pipe line are simulated using the standard κ-ε turbulent model and a simple and convenient numerical method of treating the unsteady conjugate heat transfer on a non-orthogonal coordinate system is developed. The unsteady conjugate heat transfer analysis method is implemented in a finite volume thermal-hydraulic computer code based on a non-staggered grid arrangement, SIMPLEC algorithm and higher-order bounded convection scheme. The finite element method is employed for the thermal stress analysis to calculate non-dimensional stress distributions at the piping wall as a function of time. Some numerical calculations are performed for a PWR pressurizer surge line pipe model with shortened length, subjected to internally thermal stratification caused either by insurge or outsurge flow with a specified velocity, and the results are discussed in detail.

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The Anti-Gravity Phenomena in EHD Heat Pipe Model

Heat Transfer, Volume 4 ◽

10.1115/imece2002-33553 ◽

2002 ◽

Cited By ~ 2

Author(s):

Jiaxiang Yang ◽

Jiancai Wang ◽

Chuntian Chen ◽

Changsheng Yu

Keyword(s):

Heat Transfer ◽

Heat Pipe ◽

Copper Wire ◽

Heat Pipes ◽

Working Fluid ◽

Dc Voltage ◽

Pipe Model ◽

Condensation Section ◽

Insulating Liquid ◽

Saturation Vapor

A heat pipe model of electrohydrodynamical (EHD) enhancement heat transfer has been designed and made. The insulating liquid was selected as working fluid and the copper wire whose diameter was 1mm was used as the high voltage electrode. The temperature in the inlet and outlet of both the vaporization section and the condensation section, the saturation vapor pressure inside this model were measured respectively under different applied dc voltage and different tilt angle, that is, the vaporization section was placed higher than the condensation section. The experiment results indicate that the circumfluence between the condensation section and the vaporization section was improved with the increase of the applied dc voltage. Such EHD enhancement heat transfer technology can be practically employed in the heat transfer engineering, and has some reference values for the investigation of heat pipes used in the case of anti-gravity.

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Analysis of pipeline transportation systems for carbon dioxide sequestration

Archives of Thermodynamics ◽

10.2478/aoter-2014-0008 ◽

2014 ◽

Vol 35 (1) ◽

pp. 117-140 ◽

Cited By ~ 12

Author(s):

Andrzej Witkowski ◽

Mirosław Majkut ◽

Sebastian Rulik

Keyword(s):

Heat Transfer ◽

Carbon Dioxide ◽

Ambient Temperature ◽

Thermal Insulation ◽

Ground Level ◽

Transportation Systems ◽

Atmospheric Conditions ◽

Insulation Layer ◽

Pipe Model ◽

The Cost

Abstract A commercially available ASPEN PLUS simulation using a pipe model was employed to determine the maximum safe pipeline distances to subsequent booster stations as a function of carbon dioxide (CO2) inlet pressure, ambient temperature and ground level heat flux parameters under three conditions: isothermal, adiabatic and with account of heat transfer. In the paper, the CO2 working area was assumed to be either in the liquid or in the supercritical state and results for these two states were compared. The following power station data were used: a 900 MW pulverized coal-fired power plant with 90% of CO2 recovered (156.43 kg/s) and the monothanolamine absorption method for separating CO2 from flue gases. The results show that a subcooled liquid transport maximizes energy efficiency and minimizes the cost of CO2 transport over long distances under isothermal, adiabatic and heat transfer conditions. After CO2 is compressed and boosted to above 9 MPa, its temperature is usually higher than ambient temperature. The thermal insulation layer slows down the CO2 temperature decrease process, increasing the pressure drop in the pipeline. Therefore in Poland, considering the atmospheric conditions, the thermal insulation layer should not be laid on the external surface of the pipeline.

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Numerical Analysis of Unsteady Conjugate Heat Transfer and Thermal Stress for a Curved Piping System Subjected to Thermal Stratification

Journal of Pressure Vessel Technology ◽

10.1115/1.1613947 ◽

2003 ◽

Vol 125 (4) ◽

pp. 467-474 ◽

Cited By ~ 11

Author(s):

Jong Chull Jo ◽

Young Hwan Choi ◽

Seok Ki Choi

Keyword(s):

Heat Transfer ◽

Thermal Stress ◽

Numerical Analysis ◽

Thermal Stratification ◽

Conjugate Heat Transfer ◽

Heat Transfer Analysis ◽

Stress Distributions ◽

Line Pipe ◽

Pipe Model ◽

Surge Line

This paper addresses three-dimensional numerical analyses of the unsteady conjugate heat transfer and thermal stress for a PWR pressurizer surge line pipe with a finite wall thickness, subjected to internally thermal stratification. A primary emphasis of the present study is placed on the investigation of the effects of surge flow direction on the determinations of the transient temperature and thermal stress distributions in the pipe wall. In the present numerical analysis, the thermally stratified flows (in-surge flow and out-surge flow) in the pipe line are simulated using the standard κ−ε turbulent model and a simple and convenient numerical method of treating the unsteady conjugate heat transfer on a non-orthogonal coordinate system is developed. The unsteady conjugate heat transfer analysis method is implemented in a finite volume thermal-hydraulic computer code based on a non-staggered grid arrangement, SIMPLEC algorithm and higher-order bounded convection scheme. The finite element method is employed for the thermal stress analysis to calculate non-dimensional stress distributions at the piping wall as a function of time. Some numerical calculations are performed for a PWR pressurizer surge line pipe model with shortened length, subjected to internally thermal stratification caused either by insurge or outsurge flow with a specified velocity, and the results are discussed in detail.

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