Cooling of Particulate Solids and Fluid in a Moving Bed Heat Exchanger

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Mustafa Turkyilmazoglu
Keyword(s):  
Heat Sink ◽  
Heat Exchangers ◽  
Solid Particles ◽  
Temperature Fields ◽  
Flowing Fluid ◽  
Moving Bed ◽  
Particulate Solids ◽  
Prime Concern ◽  
Cooling Effects ◽  
Energy Equations

Abstract The current technical brief is to analytically solve the coupled energy equations governing the thermal phenomenon of particulate solids and cooling fluid present inside moving bed heat exchangers constructed via a parallel plate system. The prime concern is to analytically evaluate the cooling effects of a heat sink (absorbent) placed within the media on the particulate and fluid and hence to obtain the relevant temperature fields for the latter. In the absence of such a source term, the solutions collapse onto the recent literature. Results clearly demonstrate how an effective cooling can be achieved with a heat sink mounted on industrial moving bed heat exchangers. Particularly, the existence of an energy sink results in cooler solid particles as compared to the flowing fluid.

Theoretical Realizability of Dream-Pipe-Like Oscillating/Pulsating Heat Pipe

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Masao Furukawa
Keyword(s):  
Heat Pipe ◽  
Heat Transport ◽  
Capillary Tube ◽  
Feasibility Studies ◽  
Temperature Fields ◽  
Pulsating Heat Pipe ◽  
Long Distance ◽  
Effective Thermal Diffusivity ◽  
Energy Equations ◽  
Adiabatic Section

The state of the art of thermally self-excited oscillatory heat pipe technology is briefly mentioned to emphasize that there exists no oscillating/pulsating heat pipe (OHP/PHP) suited to long-distance heat transport. Responding to such conditions, this study actively proposes a newly devised conceptually novel type of OHP/PHP. In that heat pipe, the adiabatic section works as it were the dream pipe invented by Kurzweg. This striking quality of the proposed new-style OHP/PHP produces high possibilities of long-distance heat transport. To support such optimistic views, an originally planned mathematical model is introduced for feasibility studies. Hydraulic considerations have first been done to understand what conditions are required for sustaining bubble-train flows in a capillary tube of interest. Theoretical analysis has then been made to solve the momentum and energy equations governing the flow velocity and temperature fields in the adiabatic section. The obtained analytical solutions are arranged to give algebraic expressions of the effective thermal diffusivity, the performance index combined with the tidal displacement, and the required electric power. Computed results of those three are displayed in the figures to demonstrate the realizability of that novel OHP.

On Combined Free and Forced Convection in Channels

1960 ◽  
Vol 82 (3) ◽  
pp. 233-238 ◽  
Author(s):  
L. N. Tao
Keyword(s):  
Forced Convection ◽  
Rectangular Channel ◽  
Complex Function ◽  
Vertical Channel ◽  
Temperature Fields ◽  
Parallel Plates ◽  
Free And Forced Convection ◽  
Energy Equations ◽  
Helmholtz Wave Equation ◽  
Transfer Problems

The heat-transfer problems of combined free and forced convection by a fully developed laminar flow in a vertical channel of constant axial wall temperature gradient with or without heat generations are approached by a new method. By introducing a complex function which is directly related to the velocity and temperature fields, the coupled momentum and energy equations are readily combinable to a Helmholtz wave equation in the complex domain. This greatly reduces the complexities of the problems. For illustrations, the cases of flows between parallel plates and in a rectangular channel are treated. It shows that this method is more direct and powerful than those of previous investigations.

scholarly journals Calculation of evaporation length of a liquid bridge flowing between inclined hot tubes

2021 ◽  
Vol 2119 (1) ◽  
pp. 012056
Author(s):  
P I Geshev
Keyword(s):  
Nonlinear Integral Equation ◽  
Boundary Integral Equations ◽  
Boundary Integral ◽  
Temperature Fields ◽  
Navier Stokes ◽  
Method Of Boundary Elements ◽  
Hydrostatic Equation ◽  
Velocity And Temperature Fields ◽  
Energy Equations ◽  
Surface Tension Forces

Abstract The bridge consists of liquid held by surface tension forces between two inclined tubes in an LNG heat exchanger. The shape of the bridge is calculated by the hydrostatic equation, which is reduced to a nonlinear integral equation and resolved by the Newton method. The velocity and temperature fields in the bridge are described by the Navier-Stokes and energy equations, respectively. They are reduced to the boundary integral equations and calculated by the method of boundary elements. Heat transfer coefficient is calculated for evaporating bridge and the length of total bridge evaporation is estimated.

Heat and Mass Transfer of Temperature-Dependent Viscosity Models in a Pipe: Effects of Thermal Radiation and Heat Generation

2020 ◽  
Vol 75 (3) ◽  
pp. 225-239 ◽  
Author(s):  
Fayyaz Ahmad ◽  
Mubbashar Nazeer ◽  
Mubashara Saeed ◽  
Adila Saleem ◽  
Waqas Ali
Keyword(s):  
Thermal Radiation ◽  
Heat Generation ◽  
Numerical Solutions ◽  
Physical Property ◽  
Solid Particles ◽  
Temperature Fields ◽  
Fluid Temperature ◽  
Temperature Dependent Viscosity ◽  
Dependent Viscosity ◽  
Increasing Trends

AbstractIn this paper, a study of the flow of Eyring-Powell (EP) fluid in an infinite circular long pipe under the consideration of heat generation and thermal radiation is considered. It is assumed that the viscosity of the fluid is an exponential function of the temperature of the fluid. The flow of fluid depends on many variables, such as the physical property of each phase and shape of solid particles. To convert the given governing equations into dimensionless form, the dimensionless quantities have been used and the resultant boundary value problem is solved for the calculation of velocity and temperature fields. The analytical solutions of velocity and temperature are calculated with the help of the perturbation method. The effects of the fluidic parameters on velocity and temperature are discussed in detail. Finite difference method is employed to find the numerical solutions and compared with the analytical solution. The magnitude error in velocity and temperature is obtained in each case of the viscosity model and plotted against the radius of the pipe. Graphs are plotted to describe the influence of various parameter EP parameters, heat generation parameter and thermal radiation parameters against velocity and temperature profiles. The fluid temperature has decreasing and increasing trends with respect to radiation and heat generations parameters, respectively.

Effect of Thermal Properties of a Coated Elastohydrodynamic Lubrication Line Contact Under Various Slide-to-Roll Ratios

2017 ◽  
Vol 139 (7) ◽  
Author(s):  
Huaiju Liu ◽  
Caichao Zhu ◽  
Zonglin Gu ◽  
Zhanjiang Wang ◽  
Jinyuan Tang
Keyword(s):  
Mechanical Properties ◽  
Thermal Properties ◽  
Elastohydrodynamic Lubrication ◽  
Temperature Fields ◽  
Line Contact ◽  
Oil Film ◽  
Line Contacts ◽  
Energy Equations ◽  
Thermal Conductivities

A numerical thermal elastohydrodynamic lubrication (EHL) model is developed for coated line contacts by considering both the mechanical properties and the thermal properties of the coating and the substrate. The temperature fields within the oil film and within the solids are solved by deriving the energy equations for the solids and the oil film. Heat continuity conditions are satisfied at the interfaces between the solids and the oil film, and the coating/substrate interfaces. Effects of the slide-to-roll ratio (SR), the thermal conductivities of the coating bodies, and the oil film on temperature fields are studied.

Theoretical Investigation in Thermoelastohydrodynamic Lubrication With Non-Newtonian Lubricants Under Heavy Load Change

2004 ◽  
Author(s):  
Mongkol Mongkolwongrojn ◽  
Kasame Thammakosol
Keyword(s):  
Initial Conditions ◽  
Solid Lubricants ◽  
Solid Particles ◽  
Time Dependent ◽  
Line Contact ◽  
Heavy Load ◽  
Steady State Condition ◽  
Load Change ◽  
Load Function ◽  
Energy Equations

The time-dependent thermal compressible elastohydrodynamic (EHD) lubrication of sliding line contact has been developed to investigate the effect of a sudden load change. The time-dependent modified Reynolds equation with non-Newtonian fluids has been formulated using power law’s model. In this study, the non-Newtonian dilatant fluids for liquids-solid lubricants have been purposed experimentally using the common solid particles namely, Molybdenum disulfide (MoS2) and Polytetrafluoroethylene (PTFE). The simultaneous systems of modified Reynolds and elasticity and energy equations with initial conditions were solved numerically using multigrid multilevel technique. The performance characteristics of the thermoelastohydrodynamic under line contact were presented with varying time for the pressure distribution, temperature distribution and oil film thickness. The transient response of the line contact between two surfaces was simulated under a heavy step load function. The coefficients of friction were also presented in this work at steady state condition with varying particle concentration. This simulation showed a significant effect of liquid-solid on thermoelastohydrodynamic (TEHD) lubrication under heavy load conditions.

CFD Analysis of Flow and Heat Transfer in a Novel Heat Sink for Electronic Devices

2010 ◽  
Author(s):  
Bladimir Ramos-Alvarado ◽  
Peiwen Li ◽  
Hong Liu ◽  
Abel Hernandez-Guerrero
Keyword(s):  
Heat Transfer ◽  
Power Consumption ◽  
Heat Sink ◽  
Electronics Cooling ◽  
Flow Channel ◽  
Heat Sinks ◽  
Temperature Fields ◽  
Pumping Power ◽  
Pressure Losses ◽  
Channel Configuration

Novel flow channel configurations in heat sinks for electronics cooling were proposed in this paper. Computational analyses were carried out to better understand the heat transfer performance, the uniformity of temperature fields of the heat sinking surface, as well as the pressure losses and pumping power in the operation of heat sinks. Comparison of the overall performance regarding to temperature uniformity on the heat sink surface and pumping power consumption was made for heat sinks having novel flow channel configurations and having traditional flow channel configurations. It has been found that the novel flow channel configuration dramatically reduces the pressure loss in the flow field. Giving the same pumping power consumption of an electronics cooling process, the temperature difference on surface of the heat sink which has novel flow channel configuration can be much lower than that of the heat sinks which have traditional flow channel configurations.

An Analytical Study of Natural Convective Heat Transfer within a Trapezoidal Enclosure

1980 ◽  
Vol 102 (4) ◽  
pp. 640-647 ◽  
Author(s):  
L. Iyican ◽  
Y. Bayazitogˇlu ◽  
L. C. Witte
Keyword(s):  
Heat Transfer ◽  
Analytical Study ◽  
Temperature Fields ◽  
Nusselt Numbers ◽  
Method Of Solution ◽  
Different Temperatures ◽  
Nonlinear Form ◽  
Trapezoidal Enclosure ◽  
Energy Equations ◽  
Rayleigh Numbers

The natural convection motion and the heat transfer within a trapezoidal enclosure with parallel cylindrical top and bottom walls at different temperatures and plane adiabatic sidewalls are studied. Two-dimensional natural convective fields for a range of Rayleigh numbers, up to 2.7 × 106, and enclosure tilt angles, 0 to 180 deg measured from vertical, are investigated. The Galerkin’s method of solution is applied to nonlinear form of the momentum and energy equations to determine the velocity and temperature fields. The average and local Nusselt numbers are also presented.

Sign in / Sign up

Export Citation Format

Share Document