Measurements of local heat flux to membrane water walls of combustion chambers

Taler, Jan; Taler, Dawid; Ludowski, Paweł

doi:10.1016/j.fuel.2013.06.033

Cited by 43 publications

(21 citation statements)

References 14 publications

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“…Steam and water enthalpies were determined using International Steam Tables [15]. The heat flux measurements using different methods are presented in [16][17][18].…”

Section: Determination Of Fuel Mass Flow Ratementioning

confidence: 99%

Computer monitoring and optimization of the steam boiler performance

Sobota

2017

E3S Web Conf.

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Abstract. The paper presents a method for determination of thermo-flow parameters for steam boilers. This method allows to perform the calculations of the boiler furnace chamber and heat flow rates absorbed by superheater stages. These parameters are important for monitoring the performance of the power unit. Knowledge of these parameters allows determining the degree of the furnace chamber slagging. The calculation can be performed in online mode and use to monitoring of steam boiler. The presented method allows to the operation of steam boiler with high efficiency.

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“…Steam and water enthalpies were determined using International Steam Tables [15]. The heat flux measurements using different methods are presented in [16][17][18].…”

Section: Determination Of Fuel Mass Flow Ratementioning

confidence: 99%

Computer monitoring and optimization of the steam boiler performance

Sobota

2017

E3S Web Conf.

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“…Various methods are used for solving inverse heat conduction problem (IHCP) to estimate surface heat flux or heat transfer coefficient. A proper understanding of combustion and heat transfer in furnaces and heat exchange on the water-steam side in tubes needs an accurate measurement of heat flux which is taken over by membrane furnace walls [1,[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Identification of boundary conditions has also great practical meaning in boiler superheaters [2].…”

Section: Measurements Of Heat Flux Absorbed By Water Walls In Combustmentioning

confidence: 99%

“…Identification of boundary conditions has also great practical meaning in boiler superheaters [2]. There are three wide categories of heat flux measurements of the boiler water-walls: (1) portable heat flux devices inserted in inspection ports [11][12][13][14][15], (2) Gardon-type heat flux meters welded to the sections of the boiler tubes [11][12][13][14], (3) tubular-type instruments located between two neighboring boiler tubes [1,2,7,8,[16][17][18][19][20][21]. Tubular-type and Gardon meters placed on the furnace tube wall in intense slagging areas can be important boiler diagnostic device for monitoring of slag deposition [2,[22][23][24].…”

Section: Measurements Of Heat Flux Absorbed By Water Walls In Combustmentioning

confidence: 99%

“…Therefore, the measurement of the heat flux absorbed by water-walls with satisfactory accuracy is a challenging task. Considerable work has been done in recent years in this field [1,2,[9][10][11][12][13][14][15][16][17][18][19][20][21]24]. Previous studies to precisely measure the local heat flux to membrane water walls in steam boilers failed due to unknown water-side heat transfer coefficients.…”

Section: Measurements Of Heat Flux Absorbed By Water Walls In Combustmentioning

confidence: 99%

“…The Levenberg-Marquardt method that was used for solving nonlinear least squares problem was also included in the Python program. This chapter is based mainly on two papers published earlier [1,2].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Solving Inverse Heat Transfer Problems When Using CFD Modeling

Ludowski¹,

Taler²,

Taler³

2016

Numerical Simulation - From Brain Imaging to Turbulent Flows

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The chapter presents solving steady-state inverse heat transfer problems using Computational Fluid Dynamics (CFD) software. Two examples illustrate the application of the proposed method. As the first inverse problem determining the absorbed heat flux to water walls in furnaces of steam boilers is presented in detail. Three different measurement devices (flux tubes) were designed to identify steady-state boundary conditions in water wall tubes of combustion chambers. The first meter is made of a short eccentric tube in which four thermocouples on the fire side below the inner and outer tube surfaces are installed. The fifth thermocouple is situated at the rear of the tube on the housing side of the water wall tube. The second meter has two longitudinal fins that are welded to the bare eccentric tube. In the third option of the instrument, the fins are attached to the water wall tubes but not to the flux tubes as in the second version of the flux tubes. The first instrument is used to measure the heat flux to water walls made from bare tubes, while another two heat flux tubes are designated for measuring the heat flux to membrane walls. Unlike the existing devices, the flux tube is not attached to neighboring water-wall tubes. The absorbed heat flux on the outer surface and the heat transfer coefficient at the inner surface of the flux tube are determined from temperature measurements at internal points. The thermal conductivity of the flux-tube material is a function of temperature. The nonlinear inverse problem of heat conduction (IHCP) is solved using the least-squares method. Three unknown parameters are determined using the Levenberg-Marquardt method. In each iteration, the temperature distribution in the cross section of the heat flux instrument is determined using the ANSYS/CFX software.Another inverse heat transfer problem will be a CFD simulation carried out for the platen superheater placed in the combustion chamber of the circulating fluidized bed (CFB) boiler. Velocity, pressure, and temperature of the steam, as well as the temperature of the tube wall with the complex cross section, were computed using the ANSYS/ CFX software. The direct and inverse problems were solved. In the first inverse problem, the heat transfer coefficient on the flue-gas side was determined based on the meas- ured steam temperature at the inlet and outlet of the three pass steam superheater. In the second inverse problem, the inlet steam temperature and the heat transfer coefficient on the flue-gas side were estimated using measured steam temperatures at selected locations of the superheater. The Levenberg-Marquardt method was also used to solve the second inverse problem. At every iteration step, a direct conjugate heat transfer problem was solved using the ANSYS/CFX software. The CFX program was called and controlled by an external program written in Python language. The LevenbergMarquardt algorithm was also included in the Python program.

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A thermal stress analysis of fluid–structure interaction applied to boiler water wall

Zhang

Yang

Nie³

et al. 2020

Asia-Pacific J Chem Eng

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Fluid-structure interaction (FSI), the combination of computational fluid dynamics and computational solid mechanics, is considered as a procedure to determine the stress or strain of the solid under the influence of flow movement. Common parameters such as pressure and temperature that existed in the fluid solver and solid solver are the core factors of date communication in FSI. This work investigated the thermal stress and deformation distribution of the vapor segment of the water wall by numerical simulation under two typical conditions of the 660-MW boiler. The ideal condition and the case with the oxide scale inside were compared to realize the peculiarity of parameter distribution. The results revealed that the peak temperature of water wall was

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Measurements of local heat flux to membrane water walls of combustion chambers

Cited by 43 publications

References 14 publications

Computer monitoring and optimization of the steam boiler performance

Computer monitoring and optimization of the steam boiler performance

Solving Inverse Heat Transfer Problems When Using CFD Modeling

A thermal stress analysis of fluid–structure interaction applied to boiler water wall

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