Soot Predictions in Higher Order Hydrocarbon Flames: Assessment of Semi-Empirical Models and Method of Moments

2017 ◽  
pp. 335-361
Author(s):  
Rohit Saini ◽  
Ashoke De
Keyword(s):  
Method Of Moments ◽  
Higher Order ◽  
Empirical Models ◽  
Hydrocarbon Flames ◽  
Semi Empirical

scholarly journals Contribution to the Study of Solid-Solid Thermal Contact Resistances--A Comparative Study

2021 ◽  
Vol 45 (4) ◽  
pp. 267-272
Author(s):  
Rahmouna Cheriet ◽  
Bourassia Bensaad ◽  
Fatiha Bouhadjela ◽  
Soufyane Belhenini ◽  
Mohammed Belharizi
Keyword(s):  
Contact Resistance ◽  
Contact Pressure ◽  
Mixed Method ◽  
Thermal Contact Resistance ◽  
Low Cost ◽  
Thermal Contact ◽  
Three Dimensional ◽  
Empirical Models ◽  
Three Dimensional Finite Element ◽  
Semi Empirical

This study presents a mixed numerical / semi-empirical approach that primarily aimed to estimate the thermal contact resistance between two solids. The results obtained by this mixed method were compared and validated by experimental measurements of this resistance. Three semi-empirical models were used, namely the Mikic model, the Yovanovich model and the Antonetti model. The three-dimensional finite element numerical simulation was used to estimate the contact pressure between the two solids. Then this contact pressure obtained numerically was compared to the hardness of the solids in contact. The findings indicated that the numerically obtained contact pressures were close to hardness. Therefore, the hardness, which is usually used as an input variable in semi-empirical models, was replaced by the contact pressure. The thermal contact resistance obtained by this mixed method was then compared with the experimental one. The outcomes obtained from this comparison turned out to be very conclusive and can therefore be used to reinforce our approach which can actually be viewed as a reliable and low-cost method for estimating the thermal contact resistance between solids in contact.

Analytical and Semi-empirical Models of Tornadoes and Downbursts

2021 ◽  
Author(s):  
Djordje Romanic ◽  
Horia Hangan
Keyword(s):  
Numerical Simulations ◽  
Stokes Equations ◽  
Empirical Models ◽  
Navier Stokes ◽  
Mean Flow ◽  
Navier Stokes Equations ◽  
Boundary Layer Equations ◽  
Simplifying Assumptions ◽  
The Individual ◽  
Semi Empirical

Analytical and semi-empirical models are inexpensive to run and can complement experimental and numerical simulations for risk analysis-related applications. Some models are developed by employing simplifying assumptions in the Navier-Stokes equations and searching for exact, but many times inviscid solutions occasionally complemented by boundary layer equations to take surface effects into account. Other use simple superposition of generic, canonical flows for which the individual solutions are known. These solutions are then ensembled together by empirical or semi-empirical fitting procedures. Few models address turbulent or fluctuating flow fields, and all models have a series of constants that are fitted against experiments or numerical simulations. This chapter presents the main models used to provide primarily mean flow solutions for tornadoes and downbursts. The models are organized based on the adopted solution techniques, with an emphasis on their assumptions and validity.

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