Heat and mass transfer and condensation interference in a laminar flow diffusion chamber

Фисенко, С. П.; Brin, A. A.

doi:10.1016/j.ijheatmasstransfer.2005.09.007

Cited by 33 publications

(17 citation statements)

References 16 publications

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“…Газокрапельні тепломасообмінні системи з ви-паровуванням рідини і конденсацією пари на по-верхні крапель мають широкий спектр практичного застосування в різних технологічних установках, в тому числі: для випаровування охолоджуючої води (в градирнях) [4], для змішування палива і окислю-вача (топкові форсунки) [7], для реалізації сушиль-них процесів (в розпилювальних сушарках) [9], для № 5 n 2015 охолодження і осушення повітря (в кондиціонерах) [11], для зменшення нагріву повітря при стисненні (в компресорах ГТУ) [6], для нанесення покриття (в нанотехнологіях) [13]. В кожному із практичних додатків для газокрапельної двофазної системи по-винні бути вибрані свої параметричні умови, які бу-дуть забезпечувати найбільш ефективне протікання основ ного технологічного процесу.…”

Section: постановка проблемиunclassified

Convective heat transfer in the contact device of gas-droplet type via utilizing the heat of steam gas mixture

Bezrodnyi¹,

Rachinskii²

2015

Collection of Scientific Publications NUS

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Abstract. There was experimentally determined the intensity of the heat in the gas-drop type contact device with centrifugal atomizer via utilizing the flue gas heat from the energy units. This research was held in a range of excessive water pressure to the nozzle (0.2 -0.6 MPa) and a bulk portion steam vapor mixture entering the device from 0.1 to 0.35. As the results of experimental studies were established the heat transfer coefficients which were attributed to the real surface drops. The results of experimental studies of heat transfer coefficients were compared with data for a single drop. It is established that the intensity of convective heat transfer from the steam system flow to a flare nozzle drops significantly higher than for a single drop. Keywords: contact utilizer; centrifugal atomizer; convective heat transfer coefficients; bulk portion steam.Анотація. Експериментально визначено інтенсивність тепловіддачі в контактному апараті газокрапельного типу з відцентровою форсункою в умовах утилізації теплоти відхідних газів енергетичних агрегатів. Дослідження проведені в діапазоні надлишкового тиску води перед форсункою (0,2 -0,6 МПа) і об'ємною долею водяної пари парогазової суміші на вході в апарат від 0,1 до 0,35. За результатами експериментальних досліджень було визначено коефіцієнти тепловіддачі, які були віднесені до реальної поверхні крапель. Отримані результати експериментальних досліджень коефіцієнтів тепловіддачі були порівняні з даними для одиночної краплі. Встановлено, що інтенсивність конвективної теловіддачі від парогазового потоку до системи крапель в факелі форсунки значно вища, ніж для одиночної краплі. Ключові слова: контактний утилізатор; відцентрова форсунка; коефіцієнти конвективного теплообміну; об'ємна доля водяної пари.Аннотация. Экспериментально определена интенсивность теплоотдачи в контактном аппарате газокапель-ного типа с центробежной форсункой в условиях утилизации теплоты отходящих газов энергетических агре-гатов. Исследования проведены в диапазоне избыточного давления воды перед форсункой (0,2 -0,6 МПа) и объемной долей водяного пара парогазовой смеси на входе в аппарат от 0,1 до 0,35. По результатам экспери-ментальных исследований были определены коэффициенты теплоотдачи, которые были отнесены к реальной поверхности капель. Полученные результаты экспериментальных исследований коэффициентов теплоотдачи были сравнены с одиночной каплей. Установлено, что интенсивность конвективной теплоотдачи от парогазо-вого потока в систему капель в факеле форсунки значительно выше, чем для одиночной капли. Ключевые слова: контактный утилизатор; центробежная форсунка; коэффициент конвективного теплообмена; объемная доля водяного пара. REFERENCES[1] Bezrodnyy M. K., Goliyad N. N., Barabash P. A., Golubev A. B., Rachinskiy A. Yu. Vliyanie vkhodnykh parametrov vody na tonkost raspyla tsentrobezhnykh forsunok [Influence of input parameters of water on a thinness of spray of centrifugal atomizers].

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Section: постановка проблемиunclassified

Convective heat transfer in the contact device of gas-droplet type via utilizing the heat of steam gas mixture

Bezrodnyi¹,

Rachinskii²

2015

Collection of Scientific Publications NUS

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“…In most applications, the carrier gas saturated by vapor is suddenly cooled down after entering the condenser with a cooled wall. [10][11][12][13][14] Experiments performed in these devices provide information on the flux of droplets with a size larger than the size detectable by a particle counter located downstream from the condenser. However, this information is not sufficient to determine the conditions at which new embryos were formed in the chamber.…”

Section: Introductionmentioning

confidence: 99%

“…The simplest method of modeling, widely used in previous works, [12][13][14] solves equations describing mass and heat transport under the assumption that the velocity profile in the condenser tube is parabolic, and the contribution of the radial velocity component is neglected. In recent works, mathematical models solving fluid dynamics with the aid of NavierStokes equations in the commercially available software Fluent have appeared, sometimes with a Fluent Fine Particle Model (FPM) extension.…”

Section: Introductionmentioning

confidence: 99%

“…Like in Clement's work, 24 the Dufour effect and thermodiffusion are neglected also in the majority of subsequent papers about the LFDC. [12][13][14][25][26][27][28][29] In pursuit of more precise results, the LFDC models including one or both of the cross diffusion transports have recently been presented. Lihavainen 13 involved thermodiffusion in his model and claims that the inclusion of the thermodiffusion exerts about a two-percent effect on the saturation ratio in the nucleation maximum, which he considered to be negligible.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Description of fluid dynamics and coupled transports in models of a laminar flow diffusion chamber

Trávníčková

Havlica

Ždı́mal

2013

The Journal of Chemical Physics

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The aim of this study is to assess how much the results of nucleation experiments in a laminar flow diffusion chamber (LFDC) are influenced by the complexity of the model of the transport properties. The effects of the type of fluid dynamic model (the steady state compressible Navier-Stokes system for an ideal gas/parabolic profile approximation) and the contributions of the coupled terms describing the Dufour effects and thermodiffusion on the predicted magnitude of the nucleation maxima and its location were investigated. This study was performed on the model of the homogeneous nucleation of an n-butanol-He vapor mixture in a LFDC. The isothermal dependencies of the nucleation rate on supersaturation were determined at three nucleation temperatures: 265 K, 270 K, and 280 K. For this purpose, the experimental LFDC data measured by A. P. Hyvärinen et al. [J. Chem. Phys. 124, 224304 (2006)] were reevaluated using transport models at different levels of complexity. Our results indicate that the type of fluid dynamical model affects both the position of the nucleation maxima in the LFDC and the maximum value of the nucleation rate. On the other hand, the Dufour effects and thermodiffusion perceptibly influence only the value of the maximal nucleation rate. Its position changes only marginally. The dependence of the maximum experimental nucleation rate on the saturation ratio and nucleation temperature was acquired for each case. Based on this dependence, we presented a method for the comparison and evaluation of the uncertainties of simpler models' solutions for the results, where we assumed that the model with Navier-Stokes equations and both coupled effects taken into account was the basis. From this comparison, it follows that an inappropriate choice of mathematical models could lead to relative errors of the order of several hundred percent in the maximum experimental nucleation rate. In the conclusion of this study, we also provide some general recommendations concerning the proper choice and setting of the mathematical model of transport processes in the LFDC.

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“…In [4], in describing nonisothermal flow of the gas flow in a tube at small Reynolds numbers under the assumption of validity of the Poiseuille profile, the Galerkin method [5,6] was used to obtain the expression for the characteristic heating length l T : where b 2.48. In particular, for an air flow at a velocity of 10 cm ⁄ s in a tube with a radius of 7.5 mm and a temperature of the wall of 300 K at atmospheric pressure, we have l T 0.04 m. Using the parameter l T , we can describe the temperature of the gas at the axis of a cylindrical channel with good accuracy by the expression…”

mentioning

confidence: 99%

Reorganization of the Poiseuille profile in nonisothermal flows in the reactor

Stankevich

Фисенко

2011

J Eng Phys Thermophy

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536.423The change in the temperature and velocity profile of the gas flow in a cylindrical reactor with variation in the reactor-wall temperature has numerically been investigated. It has been shown that the use of the Poiseuille profile in calculating the transient temperature profile of such a flow is quite justified. The appearance of two extrema of the radial velocity of the indicated flow on its heating (cooling) has been predicted. The maximum radial flow velocity reaches several percent of its initial average velocity.

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Heat and mass transfer and condensation interference in a laminar flow diffusion chamber

Cited by 33 publications

References 16 publications

Convective heat transfer in the contact device of gas-droplet type via utilizing the heat of steam gas mixture

Convective heat transfer in the contact device of gas-droplet type via utilizing the heat of steam gas mixture

Description of fluid dynamics and coupled transports in models of a laminar flow diffusion chamber

Reorganization of the Poiseuille profile in nonisothermal flows in the reactor

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