Boiling heat transfer modelling: A review and future prospectus (original) (raw)
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Developed boiling heat transfer : physical models, correlations and lines of further research
2007
A keynote lecture discusses current status of research of developed boiling heat transfer. An analysis of the main experimental facts, physical models and correlations of experimental data on heat transfer coefficient (HTC) is carried out. Exclusive character of developed boiling heat transfer law resulted by control of HTC by thermodynamic conditions on nucleation sites (a model of “the theatre of director” (MTD)) is highlighted. MTD-based correlation is discussed and the results of comparison with wide experimental data on HTC during developed boiling of all types of liquids (water, organic liquids, refrigerants, cryogenic liquids, liquid metals) are presented (without dividing of liquids into groups and without matching different constants and powers to different surface-fluid combinations). Unified interpretation of developed boiling heat transfer mode and diverse specific boiling heat transfer regimes (including boiling heat transfer hysteresis) is offered based on MTD and mult...
Volume 3, 2004
Numerical simulations of boiling flows are discussed. The change of phase from liquid to vapor and vice-versa usually takes place in a highly unsteady manner where the phase boundary is very convoluted. Direct numerical simulations therefore require the accurate solution of the Navier-Stokes equations and the energy equation in each phase and the correct incorporation of the unsteady phase boundary. Such simulations, where the motion of an unsteady phase boundary is followed for a sufficiently long time to allow computation of average heat transfer are very recent. Here, we will describe one method that has been used successfully to simulate boiling flows and show a few examples of studies using the method.
International Journal of Heat and Mass Transfer
A hybrid thermal lattice Boltzmann (LB) model is presented to simulate thermal multiphase flows with phase change based on an improved pseudopotential LB approach [Q. Li, K. H. Luo, and X. J. Li, Phys. Rev. E 87, 053301 (2013)]. The present model does not suffer from the spurious term caused by the forcing-term effect, which was encountered in some previous thermal LB models for liquid-vapor phase change. Using the model, the liquid-vapor boiling process is simulated. The boiling curve together with the three boiling stages (nucleate boiling, transition boiling, and film boiling) is numerically reproduced in the LB community for the first time. The numerical results show that the basic features and the fundamental characteristics of boiling heat transfer are well captured, such as the severe fluctuation of transient heat flux in the transition boiling and the feature that the maximum heat transfer coefficient lies at a lower wall superheat than that of the maximum heat flux. Furthermore, the effects of the heating surface wettability on boiling heat transfer are investigated. It is found that an increase in contact angle promotes the onset of boiling but reduces the critical heat flux, and makes the boiling process enter into the film boiling regime at a lower wall superheat, which is consistent with the findings from experimental studies.
Prediction of binary mixture boiling heat transfer coefficients using only phase equilibrium data
International journal of heat and mass transfer, 1983
A new method for predicting the variation of nucleate pool boiling heat transfer coefficients with composition for binary liquid mixtures is presented. It is shown that the rise in the local boiling point of the liquid, !1I;,p. adjacent to the heated surface caused by preferential evaporation of the volatile component has a limit at the peak nucleate heat flux. !' J.T b p can be determined from knowledge of only the phase equilibrium diagram at the pressure of interest. The resulting equation incorporating AT b P accurately predicts published experimental boiling heat transfer coefficients at heat fluxes well below the peak heat flux for six binary liquid mixture systems considered: ethanol-water, acetone-water, ethanol-benzene, nitrogen-argon, nitrogenoxygen, and nitrogen-methane.
Introduction and Mathematical Analysis to Heat Transfer by Boiling
Introduction and Mathematical Analysis to Heat Transfer by Boiling, 2024
Boiling heat transfer is a critical process in various industries, efficiently transferring heat through the phase change of a liquid to vapor. This thermal phenomenon is essential in applications ranging from power generation to chemical processing, influencing design and safety considerations. Understanding its mechanisms and factors affecting efficiency can significantly optimize energy use in heating and cooling systems. Boiling heat transfer is integral to numerous industrial and engineering processes. It underpins the efficiency and functionality of systems ranging from large-scale power plants to compact electronic devices. By harnessing the principles of boiling heat transfer, engineers can design systems that effectively manage thermal energy, leading to innovations in various sectors. In power plants, the efficiency of steam generation and thus electricity production can be significantly increased by optimizing boiling heat transfer processes.
Towards the direct numerical simulation of nucleate boiling flows
International Journal of Multiphase Flow, 2014
A flow model is built to capture evaporating interfaces separating liquid and vapour. Surface tension, heat conduction, Gibbs free energy relaxation and compressibility effects are considered. The corresponding flow model is hyperbolic, conservative and in agreement with the second law of thermodynamics. Phase transition is considered through Gibbs energy relaxation, in the same mind as in . Surface tension effects are modelled following the lines of . There is thus no need to resolve the interface structure as jump conditions are inherent features of the model formulation. With the present approach, the same set of partial differential equations is solved everywhere, in pure fluids as well as in the captured diffuse interface. There is thus a unique hyperbolic flow solver that handles flow dynamics, interface motion and eventually acoustic wave dynamics. To make distinction between ''pure'' fluids and liquid-vapour mixture treatment, different sets of algebraic equations are considered in the relaxation solver. To guarantee accurate computation of the liquid and gas dynamics the preconditioned implicit scheme of is adapted to the present boiling flow model. The model and method are validated against a one-dimensional test problem having exact solution. Multidimensional computations are then shown to illustrate method capabilities.
Survey of heat transfer correlations in forced convection boiling
Warme- und Stoffubertragung, 1980
A critical survey was conducted of the most relevant correlations of boiling heat transfer for water in forced convection flow. Most of the investigations carried out on partial nucleate boiling and fully developed nucleate boiling have led to the formulation of correlations which cannot cover a wide range of operating conditions, due to the empirical approach considered. A comparative analysis is therefore required in order to define the accuracy of the proposed correlations, on the basis of the experimental data presently available. The survey allows the accuracy of the different calculating procedures to be evaluated. The results obtained also indicate the most reliable heat transfer correlations for the different operating conditions investigated. This survey was developed considering five pressure ranges (up to 180 bar) for both saturation and subcooled boiling conditions.
Boiling Heat Transfer: Convection Controlled by Nucleation
Heat Transfer - Models, Methods and Applications, 2018
Due to the peculiar way of evolution of boiling heat transfer research, a model "theater of director" (MTD), pumping effect of growing bubble (PEGB) and MTD-based universal correlation (UC) remain beyond the attention of researchers for more than half a century. In parallel, there are periodic fundamental events, demonstrating the irrationality of such indifference. Since the 1980s, not having found a way to enhance boiling heat transfer, other than that uncovered by the MTD-UC, high-performance boiling surfaces are being developed by artificially increasing effective radius (ER) of nucleation centers (bypassing the reference to the relevant theoretical basis). In 2009, an independent review declares transient conduction and microconvection as the dominant boiling heat transfer mechanism, not knowing that this is just the PEGB. In 2014-2017, the real versatility and accuracy of the UC is confirmed by independent studies, which involve extensive databases on the pool and flow boiling (with some interpretation problems). Assessing the current status of the study, the chapter emphasizes the complete fiasco of traditionally adopted approaches, models and theories, led to the dominance of purely empirical relationships written in a dimensionless form. Heat transfer research community is invited to gain will and rid of the heavy burden of the past.
Development of non-dimensional two phase heat transfer correlation based on physics of boiling
International Journal of Thermal Sciences, 2020
The present paper discusses a new approach for predicting the nucleate boiling transfer coefficient based on the physics of nucleate boiling at atmospheric pressure under saturated conditions. Therefore, a non-dimensional correlation of the nucleate boiling heat transfer coefficient developed as a function of bubble departure diameter, active nucleation site density, and bubble departure frequency. A non-dimensional correlation using nondimensional numbers such as Bond number (Bo), Prandtl number (Pr), Capillary number (Ca), and Jakob number (Ja) is proposed to predict nucleate boiling heat transfer coefficient. The Buckingham π-theorem is used to develop these non-dimensional numbers. The developed non-dimensional correlation of the bubble departure diameter (Bo) and frequency (Ca*) found to predict the present and experimental data of other investigator within an error of �12% and �15%, respectively. The non-dimensional nucleate boiling heat transfer coefficient (Nu) correlation based on the non-dimensional numbers found to predict own and other experimental data within an error of �15%. The result shows the interdependency of bubble dynamic parameters to predict the nucleate boiling heat transfer coefficient.