Thermophysical properties of greenhouse gases thermal conductivity and dynamic viscosity as function of temperature and pressure

1996 ◽  
Vol 37 (6-8) ◽  
pp. 1291-1296 ◽  
Author(s):  
G. Latini ◽  
G. Passerini ◽  
F. Polonara
Keyword(s):  
Thermal Conductivity ◽  
Greenhouse Gases ◽  
Thermophysical Properties ◽  
Dynamic Viscosity ◽  
Temperature And Pressure

scholarly journals Enhancement of heat transfer coefficient multi-metallic nanofluid with ANFIS modeling for thermophysical properties

2015 ◽  
Vol 19 (5) ◽  
pp. 1613-1620 ◽  
Author(s):  
Hyder Balla ◽  
Shahrir Abdullah ◽  
Wan Faizal ◽  
Rozli Zulkifli ◽  
Kamaruzaman Sopian
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Thermophysical Properties ◽  
Dynamic Viscosity ◽  
Base Fluid ◽  
Volume Fractions ◽  
The Heat Transfer Coefficient ◽  
Cu And Zn

Cu and Zn-water nanofluid is a suspension of the Cu and Zn nanoparticles with the size 50 nm in the water base fluid for different volume fractions to enhance its Thermophysical properties. The determination and measuring the enhancement of Thermophysical properties depends on many limitations. Nanoparticles were suspended in a base fluid to prepare a nanofluid. A coated transient hot wire apparatus was calibrated after the building of the all systems. The vibro-viscometer was used to measure the dynamic viscosity. The measured dynamic viscosity and thermal conductivity with all parameters affected on the measurements such as base fluids thermal conductivity, volume factions, and the temperatures of the base fluid were used as input to the Artificial Neural Fuzzy inference system to modeling both dynamic viscosity and thermal conductivity of the nanofluids. Then, the ANFIS modeling equations were used to calculate the enhancement in heat transfer coefficient using CFD software. The heat transfer coefficient was determined for flowing flow in a circular pipe at constant heat flux. It was found that the thermal conductivity of the nanofluid was highly affected by the volume fraction of nanoparticles. A comparison of the thermal conductivity ratio for different volume fractions was undertaken. The heat transfer coefficient of nanofluid was found to be higher than its base fluid. Comparisons of convective heat transfer coefficients for Cu and Zn nanofluids with the other correlation for the nanofluids heat transfer enhancement are presented. Moreover, the flow demonstrates anomalous enhancement in heat transfer nanofluids.

scholarly journals SINGLE-PHASE AND TWO-PHASE SECONDARY COOLANTS: SIMULATION AND EVALUATION OF THEIR THERMOPHYSICAL PROPERTIES

2011 ◽  
Vol 4 ◽  
pp. 91
Author(s):  
Pedro Samuel Gomes Medeiros ◽  
Cleiton Rubens Formiga Barbosa ◽  
Francisco De Assis Oliveira Fontes
Keyword(s):  
Thermal Conductivity ◽  
Thermophysical Properties ◽  
Dynamic Viscosity ◽  
Single Phase ◽  
Thermal Storage ◽  
Heat Transfer Fluid ◽  
Viscosity Data ◽  
Ice Slurry ◽  
Two Phase ◽  
Cooling Systems

This paper makes a comparative analysis of the thermophysical properties of ice slurry with conventional single-phase secondary fluids used in thermal storage cooling systems. The ice slurry is a two-phase fluid consisting of water, antifreeze and ice crystals. It is a new technology that has shown great energy potential. In addition to transporting energy as a heat transfer fluid, it has thermal storage properties due to the presence of ice, storing coolness by latent heat of fusion. The single-phase fluids analyzed are water-NaCl and water-propylene glycol solutions, which also operate as carrier fluids in ice slurry. The presence of ice changes the thermophysical properties of aqueous solutions and a number of these properties were determined: density, thermal conductivity and dynamic viscosity. Data were obtained by software simulation. The results show that the presence of 10% by weight of ice provides a significant increase in thermal conductivity and dynamic viscosity, without causing changes in density. The rheological behavior of ice slurries, associated with its high viscosity, requires higher pumping power; however, this was not significant because higher thermal conductivity allows a lower mass flow rate without the use of larger pumps. Thus, the ice slurry ensures its high potential as a secondary fluid in thermal storage cooling systems, proving to be more efficient than single-phase secondary fluids.

Thermophysical Properties and Pool Boiling Characteristics of Water in Polyalphaolefin Nanoemulsion Fluids

2012 ◽  
Author(s):  
Jiajun Xu ◽  
Bao Yang
Keyword(s):  
Thermal Conductivity ◽  
Thermophysical Properties ◽  
Dynamic Viscosity ◽  
Self Assembly ◽  
Pool Boiling ◽  
Water Concentration ◽  
Interesting Phenomenon ◽  
Conductivity Increase ◽  
Thermal Conductivity Increase ◽  
Measured Thermal Conductivity

In this work, thermophysical properties and pool boiling characteristics of water-in-polyalphaolefin (PAO) nanoemulsion fluids and their dependence on water concentration have been investigated experimentally. Water-in-PAO nanoemulsion fluids are formed via self-assembly with surfactant sodium sullfosuccinate (AOT). Thermal conductivity of the fluids is found to increase with water concentration, as expected from the Maxwell equation. However, the measured thermal conductivity increase is very moderate, e.g., a 16% increase for 8.6Vol. %. Unlike thermal conductivity, the dynamic viscosity of these nanoemulsion fluids first increases with water concentration, reaches a maximum, and then decreases. This trend could be attributed to the attractive forces among water droplets. The boiling behavior of these nanoemulsion fluids has been altered due to water nanodroplets. Adding water nanodroplets can lower the nanoemulsion’s boiling point compared to the pure PAO. Another interesting phenomenon observed is that pool boiling of nanoemulsion fluids randomly follows two different curves when the water concentration is in the range of 5.3 Vol. % to 7.8 Vol. %. The mechanism underlying this phenomenon is not understood yet, but it may be related to the evolution of microstructures in the water-in-PAO nanoemulsion fluids.

scholarly journals Development of Simple-to-Use Predictive Models to Determine Thermal Properties of Fe2O3/Water-Ethylene Glycol Nanofluid

Computation ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 18 ◽  
Author(s):  
Mohammad Hossein Ahmadi ◽  
Ali Ghahremannezhad ◽  
Kwok-Wing Chau ◽  
Parinaz Seifaddini ◽  
Mohammad Ramezannezhad ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Neural Networks ◽  
Artificial Neural Networks ◽  
Thermophysical Properties ◽  
Predictive Models ◽  
Dynamic Viscosity ◽  
Least Square ◽  
Support Vector ◽  
Mass Ratio ◽  
Artificial Neural

Thermophysical properties of nanofluids play a key role in their heat transfer capability and can be significantly affected by several factors, such as temperature and concentration of nanoparticles. Developing practical and simple-to-use predictive models to accurately determine these properties can be advantageous when numerous dependent variables are involved in controlling the thermal behavior of nanofluids. Artificial neural networks are reliable approaches which recently have gained increasing prominence and are widely used in different applications for predicting and modeling various systems. In the present study, two novel approaches, Genetic Algorithm-Least Square Support Vector Machine (GA-LSSVM) and Particle Swarm Optimization- artificial neural networks (PSO-ANN), are applied to model the thermal conductivity and dynamic viscosity of Fe2O3/EG-water by considering concentration, temperature, and the mass ratio of EG/water as the input variables. Obtained results from the models indicate that GA-LSSVM approach is more accurate in predicting the thermophysical properties. The maximum relative deviation by applying GA-LSSVM was found to be approximately ±5% for the thermal conductivity and dynamic viscosity of the nanofluid. In addition, it was observed that the mass ratio of EG/water has the most significant impact on these properties.

Thermal conductivity and dynamic viscosity of dielectric liquids in electric fields

2002 ◽  
Author(s):  
B.V. Savinykh ◽  
I. R. Sagbiev ◽  
A. A. Mukhamadiev ◽  
F. M. Gumerov ◽  
B. Le Niendre
Keyword(s):  
Thermal Conductivity ◽  
Electric Fields ◽  
Dynamic Viscosity ◽  
Dielectric Liquids

Temperature and Pressure Dependences of the Effective Thermal Conductivity of Granites

2020 ◽  
Vol 84 (9) ◽  
pp. 1144-1146
Author(s):  
S. N. Emirov ◽  
A. A. Aliverdiev ◽  
V. D. Beybalaev ◽  
A. A. Amirova ◽  
R. M. Aliev ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Temperature And Pressure

scholarly journals Thermophysical Properties of Cement Mortar Containing Waste Glass Powder

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 488
Author(s):  
Oumaima Nasry ◽  
Abderrahim Samaouali ◽  
Sara Belarouf ◽  
Abdelkrim Moufakkir ◽  
Hanane Sghiouri El Idrissi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Specific Heat ◽  
Thermophysical Properties ◽  
Glass Powder ◽  
Cement Mortar ◽  
Soda Lime ◽  
Waste Glass ◽  
Soda Lime Glass ◽  
Volumetric Specific Heat ◽  
Waste Glass Powder

This study aims to provide a thermophysical characterization of a new economical and green mortar. This material is characterized by partially replacing the cement with recycled soda lime glass. The cement was partially substituted (10, 20, 30, 40, 50 and 60% in weight) by glass powder with a water/cement ratio of 0.4. The glass powder and four of the seven samples were analyzed using a scanning electron microscope (SEM). The thermophysical properties, such as thermal conductivity and volumetric specific heat, were experimentally measured in both dry and wet (water saturated) states. These properties were determined as a function of the glass powder percentage by using a CT-Meter at different temperatures (20 °C, 30 °C, 40 °C and 50 °C) in a temperature-controlled box. The results show that the thermophysical parameters decreased linearly when 60% glass powder was added to cement mortar: 37% for thermal conductivity, 18% for volumetric specific heat and 22% for thermal diffusivity. The density of the mortar also decreased by about 11% in dry state and 5% in wet state. The use of waste glass powder as a cement replacement affects the thermophysical properties of cement mortar due to its porosity as compared with the control mortar. The results indicate that thermal conductivity and volumetric specific heat increases with temperature increase and/or the substitution rate decrease. Therefore, the addition of waste glass powder can significantly affect the thermophysical properties of ordinary cement mortar.

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