scholarly journals Impact of double skin facade constructional features on heat transfer and fluid dynamic behaviour

2021 ◽  
pp. 107796
Author(s):  
Aleksandar Jankovic ◽  
Francesco Goia
Keyword(s):  
Heat Transfer ◽  
Dynamic Behaviour ◽  
Fluid Dynamic ◽  
Double Skin

Paper 12: Derivation of Furnace Heat Transfer from Fluid Dynamic Behaviour

1965 ◽  
Vol 180 (10) ◽  
pp. 109-117
Author(s):  
D. Anson
Keyword(s):  
Heat Transfer ◽  
Dynamic Behaviour ◽  
Fluid Dynamic ◽  
Radiant Heat ◽  
Local Heat ◽  
Radiant Heat Transfer ◽  
Release Rates ◽  
Air Mixing ◽  
Mixing Rates ◽  
The Relationship

The principles underlying radiant heat transfer in boiler furnaces are fundamentally simple, but their application requires a knowledge of empirical quantities describing the emissivity of the flame and the boiler surfaces and the relationship between their geometries. This paper draws attention to the dependence of local heat release rates on fuel/air mixing. In the case of a downshot coal-fired furnace, the performance of which was investigated in detail, the size and position of the effective flame envelope could be derived from a knowledge of the flow and mixing rates. These in turn should be capable of being measured on isothermal models, and research should be directed to this end.

scholarly journals Experimental performance comparison between circular and elliptical tubes in evaporative condensers

2021 ◽  
Author(s):  
Giuseppe Starace ◽  
Lorenzo Falcicchia ◽  
Pierpaolo Panico ◽  
Maria Fiorentino ◽  
Gianpiero Colangelo
Keyword(s):  
Heat Transfer ◽  
Experimental Approach ◽  
Fluid Dynamic ◽  
Major Axis ◽  
Performance Comparison ◽  
Operating Conditions ◽  
Condensation Temperature ◽  
Air Cooled Condensers ◽  
Reduced Scale ◽  
Dynamic Phenomena

AbstractIn refrigeration systems, evaporative condensers have two main advantages compared to other condensation heat exchangers: They operate at lower condensation temperature than traditional air-cooled condensers and require a lower quantity of water and pumping power compared to evaporative towers. The heat and mass transfer that occur on tube batteries are difficult to study. The aim of this work is to apply an experimental approach to investigate the performance of an evaporative condenser on a reduced scale by means of a test bench, consisting of a transparent duct with a rectangular test section in which electric heaters, inside elliptical pipes (major axis 32 mm, minor axis 23 mm), simulate the presence of the refrigerant during condensation. By keeping the water conditions fixed and constant, the operating conditions of the air and the inclination of the heat transfer geometry were varied, and this allowed to carry out a sensitivity analysis, depending on some of the main parameters that influence the thermo-fluid dynamic phenomena, as well as a performance comparison. The results showed that the heat transfer increases with the tube surface exposed directly to the air as a result of the increase in their inclination, that has been varied in the range 0–20°. For the investigated conditions, the average increase, resulting by the inclination, is 28%.

Turbulent Transport in Pin Fin Arrays: Experimental Data and Predictions

2005 ◽  
Author(s):  
F. E. Ames ◽  
L. A. Dvorak
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Boundary Layers ◽  
Fluid Dynamic ◽  
Turbulent Transport ◽  
Turbulence Models ◽  
Reynolds Numbers ◽  
Velocity Profiles ◽  
Pin Fin ◽  
Pin Fin Arrays

The objective of this research has been to experimentally investigate the fluid dynamics of pin fin arrays in order to clarify the physics of heat transfer enhancement and uncover problems in conventional turbulence models. The fluid dynamics of a staggered pin fin array have been studied using hot wire anemometry with both single and x-wire probes at array Reynolds numbers of 3000; 10,000; and 30,000. Velocity distributions off the endwall and pin surface have been acquired and analyzed to investigate turbulent transport in pin fin arrays. Well resolved 3-D calculations have been performed using a commercial code with conventional two-equation turbulence models. Predictive comparisons have been made with fluid dynamic data. In early rows where turbulence is low, the strength of shedding increases dramatically with increasing in Reynolds numbers. The laminar velocity profiles off the surface of pins show evidence of unsteady separation in early rows. In row three and beyond laminar boundary layers off pins are quite similar. Velocity profiles off endwalls are strongly affected by the proximity of pins and turbulent transport. At the low Reynolds numbers, the turbulent transport and acceleration keep boundary layers thin. Endwall boundary layers at higher Reynolds numbers exhibit very high levels of skin friction enhancement. Well resolved 3-D steady calculations were made with several two-equation turbulence models and compared with experimental fluid mechanic and heat transfer data. The quality of the predictive comparison was substantially affected by the turbulence model and near wall methodology.

Numerical Simulation of Indoor Thermal Environment of a Double-Skin Facade Office with Different Shutter Angles

2014 ◽  
Vol 694 ◽  
pp. 256-259
Author(s):  
Xin Zhan ◽  
Hua Yang ◽  
Feng Yun Jin
Keyword(s):  
Heat Transfer ◽  
Thermal Environment ◽  
Ventilation Rate ◽  
Air Distribution ◽  
Indoor Thermal Environment ◽  
Double Skin ◽  
Computational Fluid Dynamics Cfd ◽  
Heat Transfer Simulation ◽  
Shading Devices ◽  
Rng Turbulence Model

Airflow and heat transfer simulation was conducted for a double-skin façade (DSF) system equipped with shading devices in the cavity, using computational fluid dynamics (CFD) with RNG turbulence model and PISO algorithm, for five conditions of slat angles (θ=0°, 30°, 45°, 60°, 90°). The present study indicates that the presence of shading devices influences the temperatures, the ventilation rate and the air distribution in the DSF system. Besides, the different angles will make different influences.

Analisis Perbandingan Jenis Material Penukar Kalor Plat Datar Aliran Silang Untuk Proses Pengeringan Kayu

2021 ◽  
Vol 9 (1) ◽  
pp. 60-71
Author(s):  
Abeth Novria Sonjaya ◽  
Marhaenanto Marhaenanto ◽  
Mokhamad Eka Faiq ◽  
La Ode M Firman
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Flat Plate ◽  
Heat Exchangers ◽  
Fluid Dynamic ◽  
Cross Flow ◽  
Plate Heat ◽  
Dry Air ◽  
Copper Material ◽  
Plate Type

The processed wood industry urgently needs a dryer to improve the quality of its production. One of the important components in a dryer is a heat exchanger. To support a durable heat transfer process, a superior material is needed. The aim of the study was to analyze the effectiveness of the application of cross-flow flat plate heat exchangers to be used in wood dryers and compare the materials used and simulate heat transfer on cross-flow flat plate heat exchangers using Computational Fluid Dynamic simulations. The results showed that there was a variation in the temperature out of dry air and gas on the flat plate heat exchanger and copper material had a better heat delivery by reaching the temperature out of dry air and gas on the flat plate type heat exchanger of successive cross flow and.   overall heat transfer coefficient value and the effectiveness value of the heat exchanger of the heat transfer characteristics that occur with the cross-flow flat plate type heat exchanger in copper material of 251.74725 W/K and 0.25.

Modelling the Dynamic Behaviour of A Motorcycle Damper

1995 ◽  
Vol 209 (4) ◽  
pp. 249-262 ◽  
Author(s):  
A L Audenino ◽  
G Belingardi
Keyword(s):  
Shock Absorber ◽  
Dynamic Behaviour ◽  
Fluid Dynamic ◽  
Critical Factor ◽  
Physical Models ◽  
Vehicle Suspension ◽  
Shock Absorbers ◽  
Internal Fluid ◽  
Output Force ◽  
Dependent Behaviour

Within the context of vehicle suspension component characterization, that of shock absorbers is one of the more difficult to achieve, yet it is a very critical factor in the prediction of vehicle dynamic behaviour. Strongly non-linear output force functions are always linked to a frequency-dependent behaviour. Using the internal fluid-dynamic phenomenon with respect to a motorcycle shock absorber, different physical models of increasing complexity are presented: using these models it is possible to evaluate the importance of different factors, for example oil compressibility or oil inertia. Comparisons with experimental data confirm the validity of these models

Critical Design Condensation Locations in Facial Masks

2010 ◽  
Author(s):  
A. M. Al-Jumaily
Keyword(s):  
Heat Transfer ◽  
Computer Simulation ◽  
Dynamic Model ◽  
Fluid Dynamic ◽  
Condensation Rate ◽  
Facial Mask ◽  
Critical Design ◽  
Life Threatening ◽  
Mass And Heat Transfer

Facial masks are the main interface between patients and breathing supportive devices. Condensation in these masks causes serious breath disturbance which could be life threatening. Based on temperature-driven mass and heat transfer formulations, a computer simulation fluid dynamic model is developed to compute the condensation rate and locations of a typical breathing facial mask. Condensation measurements are taken to validate the model. The effects of mask geometry and shape on condensation are elaborated on.

Heat Transfer Performance of Aluminum Foams

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Simone Mancin ◽  
Claudio Zilio ◽  
Luisa Rossetto ◽  
Alberto Cavallini
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Pressure Drop ◽  
Fluid Dynamic ◽  
Foam Core ◽  
Aluminum Foams ◽  
Experimental Heat ◽  
High Heat Transfer ◽  
Experimental Heat Transfer ◽  
Core Height

Because of their interesting heat transfer and mechanical properties, metal foams have been proposed for several different applications, thermal and structural. This paper aims at pointing out the effective thermal fluid dynamic behavior of these new enhanced surfaces, which present high heat transfer area per unit of volume at the expense of high pressure drop. The paper presents the experimental heat transfer and pressure drop measurements relative to air flowing in forced convection through four different aluminum foams, when electrically heated. The tested aluminum foams present 5, 10, 20 and 40 PPI (pores per inch), porosity around 0.92–0.93, and 0.02 m of foam core height. The experimental heat transfer coefficients and pressure drops have been obtained by varying the air mass flow rate and the electrical power, which has been set at 25.0 kW m−2, 32.5 kW m−2, and 40.0 kW m−2. The results have been compared against those measured for 40 mm high samples, in order to study the effects of the foam core height on the heat transfer. Moreover, predictions from two recent models are compared with heat transfer coefficient and pressure drop experimental data. The predictions are in good agreement with experimental data.

Numerical Analysis on Nanofluid Forced Convection in Ducts With Triangular Cross Sections

2011 ◽  
Author(s):  
O. Manca ◽  
S. Nardini ◽  
D. Ricci ◽  
S. Tamburrino
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Forced Convection ◽  
Cross Sections ◽  
Fluid Dynamic ◽  
Pure Water ◽  
Convection Flow ◽  
Uniform Heat Flux ◽  
Surface Shear Stress ◽  
Surface Shear

Heat transfer of fluids is very important to many industrial heating or cooling equipments. Convective heat transfer can be enhanced passively by changing flow geometry, boundary conditions or by enhancing the thermal conductivity of the working fluids. An innovative way of improving the fluid thermal conductivity is to introduce suspended small solid nanoparticles in the base fluids. In this paper a numerical investigation on laminar forced convection flow of a water–Al2O3 nanofluid in a duct having an equilateral triangular cross section is performed. The hydraulic diameter is set equal to 1.0×10−2 m. A constant and uniform heat flux on the external surfaces has been applied and the single-phase model approach has been employed. The analysis has been run in steady state regime for a nanoparticle size equal to 38 nm, considering different volume particle concentrations. The CFD code Fluent has been employed in order to solve the tri-dimensional numerical model. Results are presented in terms of temperature and velocity distributions, surface shear stress and heat transfer convective coefficient, Nusselt number and required pumping power profiles. Comparison with results related to the fluid dynamic and thermal behaviors in pure water are carried out in order to evaluate the enhancement due to the presence of nanoparticles in terms of volumetric concentration.

Sign in / Sign up

Export Citation Format

Share Document