Heat and mass transfer in annular liquid jets: I. Formulation

نویسنده

  • Juan I. Ramos
چکیده

Heat and mass transfer phenomena in annular liquid jets are analyzed at high Reynolds numbers by means of a model derived from the governing equations that takes into account the e€ects of surface tension and boundary conditions at the gas± liquid interfaces and the large di€erences between the thermal and mass di€usivities, densities, dynamic viscosities, and thermal conductivities between gases and liquids. The model clearly illustrates the sti€ness in both space and time associated with the concentration, linear momentum and energy boundary layers, and the initial cooling of the gases enclosed by the jet when, starting from a steady state where gases are injected into the volume enclosed by the jet at a rate equal to the heat and mass absorption rates by the liquid, gas injection is stopped. It is shown that, owing to the non-linear integrodi€erential coupling between the ̄uid dynamics and heat and mass transfer processes, the pressure of the gases enclosed by the jet may vary in either a monotonic or an oscillatory manner depending on the large number of non-dimensional parameters that govern the heat and mass transfer phenomena. For the underpressurized jets considered here, it is shown that thermal equilibrium is achieved at a much faster rate than that associated with mass transfer, double di€usive phenomena in the liquid may occur, and the mass and volume of the gases enclosed by the jet may increase or decrease as functions of time until a steady equilibrium condition is reached. Ó 2000 Elsevier Science Inc. All rights reserved.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Heat and mass transfer in annular liquid jets: II. g-jitter

The e€ects of g-jitter on heat and mass transfer in underpressurized, annular liquid jets are analyzed numerically as a function of the amplitude and frequency of the gravitational modulation by means of a mapping technique that transforms the timedependent geometry of these jets into a unit square and a conservative ®nite di€erence method. It is shown that the pressure coecient, gas concentra...

متن کامل

Heat and mass transfer in annular liquid jets: III. Combustion within the volume enclosed by the jet

The nonlinear dynamics of and heat and mass transfer processes in annular liquid jets are analyzed by means of a nonlinear system of integrodi€erential equations which account for the liquid motion and the gases enclosed by the jet. Both linear and sinusoidal heat and mass addition sources are considered to take place homogeneously within the volume enclosed by the jet's inner interface in an a...

متن کامل

Heat Transfer under Double Turbulent Pulsating Jets Impinging on a Flat Surface

In this study, the numerical analysis of turbulent flow and heat transfer of double pulsating impinging jets on a flat surface has been investigated. The unsteady two-dimensional numerical solution for two similar and dissimilar jets was performed using the RNG k-ε model. The results showed that the RNG k-ε model has more satisfactory predictions of the Nusselt number distribution. Comparisons ...

متن کامل

Enhancement of Natural Convection Heat Transfer in Annular Enclosures

Natural convection heat transfer was investigated experimentally in a concentric-cylinders annulus. To enhance the rate of heat transfer, pin fins were installed on the surface of the inner cylinder. Two fin arrangements were employed, namely, staggered and in-line arrangements. The length of the fins varied from 2 to 8 cm and the Rayleigh number Ra changed in the range from 5 x 105  to 5 x 106...

متن کامل

Modeling of A Single Turn Pulsating Heat Pipe based on Flow Boiling and Condensation Phenomena

Demand for high-performance cooling systems is one of the most challenging and virtual issues in the industry and Pulsating heat pipes are effective solutions for this concern. In the present study, the best predictor correlations of flow boiling and condensation are taken into account to model a single turn pulsating heat pipe mathematically. These considerations, result in derivation of more ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:
  • Applied Mathematics and Computation

دوره 110  شماره 

صفحات  -

تاریخ انتشار 2000