Effect Of Internal Circulation Research Articles

Research on Real Estate Wealth Effect under the Background of Double Cycle Based on VAR Model

In order to cope with the complex and severe development situation at home and abroad, in May 2020, the Party Central Committee proposed to accelerate the formation of a new development pattern with the domestic cycle as the main body and the mutual promotion of the domestic and international double cycles. Among them, the consumption of Chinese residents is a “double cycle” key part of strategy. From the perspective of consumption structure and property structure, real estate is an important part of household property and an important consumer object in China and it has a decisive influence on the effect of internal circulation. By constructing a real estate wealth effect model, this paper adopted the impulse response function method based on the VAR model, studies the changes in real estate prices, residents’ incomes, and residents’ consumption. The results show that the three interact with each other. In the long run, real estate has a positive wealth effect, but in the short term, there is a negative wealth effect, and consumers’ expectations of future housing prices will affect current consumption changes. In order to promote the domestic cycle, the author proposes to develop and improve the primary and secondary housing markets to ensure the liquidity of real estate, thereby stimulating consumption; guide residents to form healthy real estate price expectations, prevent large fluctuations in housing prices, and strictly stabilize consumption; the policy positioning of “no speculation” reduces the crowding-out effect of investment and speculative house purchases on residents’ daily consumption, thereby increasing consumption.

Separated Phase Analysis of Heat Transfer in Liquid–Liquid Taylor Flow in a Miniscale Straight Tube

Abstract Heat transfer analysis of liquid–liquid Taylor flow in previous studies almost never shows the effect of slug length on heat transfer. The homogenous or single-phase analysis is often the only method available to deal with flow of multicomponents. In this study, a new approach is developed to model the segmented liquid–liquid Taylor flow as two separated systems to present heat transfer enhancement for each component. The effect of internal circulation and boundary layer renewal within the two fluid components is clearly observed. An experimental setup was assembled using an open loop system at miniscale size in which liquid–liquid Taylor flow is heated under a constant wall temperature. Three silicone oils of 1, 3, and 5 cSt were segmented using distilled water at three volume fractions 0.25, 0.5, and 0.75. Finally, heat transfer data of the dimensionless mean wall heat flux shows good agreement with a predictive model proposed in an earlier work by the second author. The results show an impact of the fluid cell dimensions on the rate of heat transfer.

Effect of viscosity ratio on the motion of drops flowing on an inclined surface

The flow of two-dimensional drops on an inclined channel is studied by numerical simulations at finite Reynolds numbers. The effect of viscosity ratio on the behaviour of the two-phase medium is examined. The flow is driven by the acceleration due to gravity, and there is no pressure gradient along the flow direction. An implicit version of the finite difference/front-tracking method was developed and used in the present study. The lateral migration of a drop is studied first. It is found that the equilibrium position of a drop moves away from the channel floor as the viscosity ratio increases. However, the trend reverses beyond a certain viscosity ratio. Simulations with 40 drops in a relatively large channel show that there exists a limiting viscosity ratio where the drops behave like solid particles, and the effect of internal circulation of drops becomes negligible. This limiting condition resembles the granular flow regime except that the effect of interstitial fluid is present. The limiting viscosity ratio depends on the flow conditions (80 for $$Re=10$$ , and 200 for $$Re=20$$ ). There are two peaks in the areal fraction distribution of drops across the channel which is different from granular flow regime. It is also found that the peak in areal fraction distribution of drops moves away from the channel floor as the inclination angle of the channel increases.

Effects of internal circulation and particle mobility during nanofluid droplet evaporation

The effect of internal circulation on evaporation of fluid droplets containing nano-sized particles is analytically investigated, where internal circulation is caused by viscous effects at the liquid–gas interface in the convective environment. The competing time scales of liquid diffusion, convection, and particle diffusion are first analyzed as influenced by gas phase velocity, relative viscosities of gas and liquid phases, and the droplet size. The results reveal the importance of internal recirculation for droplets of practical sizes. To demonstrate the role of internal circulation plays on particle distribution and shell formation during the evaporation process, a symmetric Hill vortex and strong circulation are assumed for solving a one-dimensional governing equation, which to yield (i) the particle redistribution during the evaporation process, (ii) the time and the size upon shell formation (i.e., the end of the first-stage evaporation/drying) due to inclusion of particles at the droplet surface, and (iii) internal particle distribution that forecast possible morphologies of particle aggregates once the drying process is complete. These results are found to be dependent upon (a) the relative time scales of liquid diffusion and particle mobility (the effect of Lewis number, Le), and (b) the relative importance or evaporation rate (K) and particle mobility (the effect of Peclet number, Pe). Comparisons with previous results without internal circulation are made, as related to the time for shell formation and possible morphologies. Such comparisons reveal some distinctly different, and surprising, phenomena during and at the end of the first-stage evaporation.

Gas absorption in a moving drop containing suspended solids

Absorption of gaseous contaminants into liquid drops is a common method for pollution reduction from waste gases. In several applications, the drops contain suspended solids, which dissolve and enhance gas absorption. Most of the research published on this subject considers the absorption process by neglecting the internal circulation inside the drop. The paper considers the effect of internal circulation on gas absorption in liquid drops. For this aim, a mathematical model based on the Whitman film theory, which also accounts for solid dissolution, chemical reaction and molecular diffusion, is developed. The model indicates that internal circulation cannot be neglected for Peclet numbers higher than 100. Under these conditions, internal circulation enhances the mass transfer as compared to the stagnant drop model. The effect of increasing the solids specific area and solubility becomes less important as the Peclet number increases. Good agreement was found between the present model and experimental data from the literature.

NUMERICAL STUDY ON COMBUSTION OF A LIQUID FUEL DROPLET

Ignition and combustion of a liquid fuel droplet injected into a hot and highly pressurized combustor are investigated numerically, including the effect of internal circulation. Ignition delay times of droplets predicted with internal circulation are almost the same as those from the diffusion limit model insofar as ignition takes near the droplet. Combustion regime maps are drawn to classify the droplet combustion phenomena according to the configuration and location of the flame with respect to initial Reynolds numbers and the surrounding gas temperatures.

Effect of internal circulation on the transport to a moving drop

The existence of internal circulation in fluid droplets has been demonstrated by a number of investigators. The internal circulation, where present, provides an important mechanism for the heat and/or mass transfer associated with a moving liquid drop. In this paper we discuss the different roles played by this mechanism in the context of a moving drop experiencing condensation (inward radial field) or evaporation (outward radial field). It is noted that the strength of the internal vortex is not only a highly useful parameter in the modelling of transport to moving drops but is also necessary in the actual evaluation of the extent of transport. We provide analytical expressions for estimating the vortex strength in circumstances where the drop translation is in the low Reynolds Number regime while the radial field has inertia. We have also numerically investigated the internal circulation in a drop translating at intermediate Reynolds number ( Re=O(100)).

Droplet vaporization model for spray combustion calculations

The re-examination of the classical droplet vaporization model is made in order to develop the simple but sufficiently accurate calculation algorithm which can be used in spray combustion calculations. The new model includes the effects of variable thermophysical properties, non-unitary Lewis number in the gas film, the effect of the Stefan flow on heat and mass transfer between the droplet and the gas, and the effect of internal circulation and transient liquid heating. To evaluate the competing simplified models of the droplet heating, the more-refined, extended model of heat transfer within a moving circulating droplet is considered. A simplified, one-dimensional ‘effective conductivity’ model is formulated for the transient liquid heating with internal circulation. As an illustration, the dynamic and vaporization histories of the droplets injected into the steady and fluctuating hot air streams are analyzed.

Steady flows inside and around a fluid sphere at low Reynolds numbers

The effects of internal circulation in bubbles and droplets have been analysed by means of a semi-analytical series-truncation method. The equations of motion are transformed into a series of coupled, ordinary, nonlinear differential equations by use of orthogonal sets. These infinite-series equations are then truncated adequately and solved numerically. Using this series-truncation method, we have evaluated the effects of different ratios (between the continuous and dispersed phases) of both density and viscosity for the flows of low Reynolds numbers. For all the density ratios investigated, the density difference has almost no effect on the drag coefficient at low Reynolds numbers. The shear stress and the drag coefficient increase with increasing viscosity ratio of droplet to ambience and decrease with increasing Reynolds number.

The Effect of Internal Circulation on the Heat Transfer of a Nuclear Reactor Containment Spray Droplet

Heat removal rates from containment spray droplets following a loss-of-coolant accident in a nuclear reactor have been calculated by three different droplet models: the complete mixing model, the m...