A range-free method to determine antoine vapor-pressure heat transfer-related equation coefficients using the Boubaker polynomial expansion scheme

2011 ◽  
Vol 85 (5) ◽  
pp. 900-902 ◽  
Author(s):  
H. Koçak ◽  
Z. Dahong ◽  
A. Yildirim
Author(s):  
J. S. Chin

A practical engineering calculation method has been formulated for commercial multicomponent fuel stagnant droplet evaporation with variable finite mass and thermal diffusivity. Instead of solving the transient liquid phase mass and heat transfer partial differential equation set, a totally different approach is used. With zero or infinite mass diffusion resistance in liquid phase, it is possible to obtain vapor pressure and vapor molecular mass based on the distillation curve of these turbine fuels. It is determined that Peclet number (Pef) is a suitable parameter to represent the mass diffusion resistance in liquid phase. The vapor pressure and vapor molecular mass at constant finite Pef is expressed as a function of finite Pef, vapor pressure, and molecular mass at zero Pef and infinite Pef. At any time step, with variable finite Pef, the above equation is still valid, and PFsPef=∞, PFsPef=0, MfvPef=∞, MfvPef=0 are calculated from PFsPef≡∞, PFsPef≡0, MfvPef≡∞, MfvPef≡0, thus PFs and Mfv can be determined in a global way which eventually is based on the distillation curve of fuel. The explicit solution of transient heat transfer equation is used to have droplet surface temperature and droplet average temperature as a function of surface Nusselt number and non-dimensional time. The effect of varying com position of multi-component fuel evaporation is taken into account by expressing the properties as a function of molecular mass, acentric factor, critical temperature, and critical pressure. A specific calculation method is developed for liquid fuel diffusion coefficient, also special care is taken to calculate the binary diffusion coefficient of fuel vapor-air in gaseous phase. The effect of Stefan flow and natural convection has been included. The predictions from the present evaporation model for different turbine fuels under very wide temperature ranges have been compared with experimental data with good agreement.


2013 ◽  
Vol 01 (05) ◽  
pp. 71-78 ◽  
Author(s):  
Omotayo Bamidele Awojoyogbe ◽  
Oluwaseun Michael Dada ◽  
Karem Boubaker ◽  
Omoniyi Adewale Adesola

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
M. A. Aweda ◽  
M. Agida ◽  
M. Dada ◽  
O. B. Awojoyogbe ◽  
K. Isah ◽  
...  

In this study, an analytical solution to the heat transfer equation in biological tissues during laser heating is presented. The results were compared to recently published numerical simulations.


2007 ◽  
Vol 44 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Junjie Yan ◽  
Yusen Yang ◽  
Shenhua Hu ◽  
Kejian Zhen ◽  
Jiping Liu

Author(s):  
Kai Wang ◽  
Edgar Molina ◽  
Ghazal Dehghani ◽  
Ben Xu ◽  
Peiwen Li ◽  
...  

A group of eutectic ternary halide salts were surveyed and studied for the objective of developing a high temperature heat transfer fluid with a freezing point below 250°C and a low vapor pressure, below 1.0 atm, at temperatures up to 800°C. The studied salts include: 1) NaCl-KCl-ZnCl2 with a mole fractions of 18.6%-21.9%-59.5% and a melting point of tm=213°C; 2) NaCl-KCl-ZnCl2 with a mole fraction of 13.4%-33.7%-52.9% and a melting point of tm=204°C; and 3) NaCl-KCl-ZnCl2 with mole fraction of 13.8%-41.9%-44.3% and a melting point of tm=229 °C. Vapor pressures of these salts at different temperatures were experimentally obtained using an in-house developed test facility. The results show that vapor pressures of all the three eutectic molten salts are below 1.0 atm at a temperature of 800 °C. The salt of ZnCl2-KCl-NaCl in mole faction of 44.3%-41.9%-13.8% has lowest vapor pressure which is only about 1.0 atm even at a temperature of 900 °C. Viscosities of these salts were measured in the temperature range from after melting to 850°C. At low temperatures near their melting points of the salts, the viscosities are about 16 × 10−3Pa s, while at high temperatures above 700°C the viscosities are around 4 × 10−3Pa s, which is satisfactorily low to serve as heat transfer fluid for circulation in a CSP system. Both the vapor pressure and the viscosities of the studied three eutectic salts demonstrated satisfaction to serve as high temperature heat transfer fluids. Other thermal and transport properties of these salts are expected to be reported in the future for screening out a satisfactory high temperature heat transfer fluid.


Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 858
Author(s):  
Titan Paul ◽  
Amitav Tikadar ◽  
Rajib Mahmud ◽  
Azzam Salman ◽  
A. K. M. Monjur Morshed ◽  
...  

In recent years, solar thermal energy (STE) has attracted energy researchers because of its higher efficacy compared to the photovoltaic solar cell. STE is one of the forms of solar energy whereby heat is transferred via a secondary medium called heat transfer fluids (HTFs). Therefore, the overall performance of STE depends on the thermophysical properties and thermal performance of the HTFs. Traditional HTFs suffer from low decomposition temperature, high melting point, and higher vapor pressure. To overcome these limitations, researchers have recently begun working on new HTFs for STE. Ionic liquids (ILs) are considered as a potential candidate for the next generation of HTFs because of their enhanced thermophysical properties, such as thermal stability at high temperature, insignificant vapor pressure, and high ionic conductivity. In addition, thermophysical properties and thermal performance of ILs can be further enhanced by dispersing nanoparticles, which is one of the emerging research interests to improve the efficiency of the solar thermal system. This paper summarizes the recent study of ILs-based nanofluids as HTFs. These summaries are divided into two sections (i) thermophysical properties studies, such as density, viscosity, thermal conductivity, and heat capacity, and (ii) thermal performance studies such as natural convection and forced convection. Synthesis of ILs-based nanofluids and thermophysical properties measurement techniques are also discussed. Based on these state-of-the-art summaries, we offer recommendations for potential future research direction for ILs-based nanofluids.


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