MATHEMATICAL MODEL OF FINNED TUBE HEAT EXCHANGERS FOR THERMAL SIMULATION SOFTWARE OF AIR CONDITIONERS

2002 ◽  
Vol 29 (4) ◽  
pp. 547-556 ◽  
Author(s):  
Metin Tuztas ◽  
A.Nilufer Egrican
Author(s):  
Maung Naing Naing Tun ◽  
Nilufer Egrican

This paper presents computer software developed for rating and optimum selection of finned circular tubes compact heat exchangers with various coil geometries. The software is developed to use as a computing tool for commercial and R&D purposes in FRITERM A.S, an original equipment manufacturer (OEM) of finned tube heat exchangers. Finned-tube heat exchangers are highly utilized in refrigeration and process industries and heat transfer and pressure drop calculations are very important to manufactures and design engineers. For this purpose, a simulation and design software to predict the performance of finned-tube heat exchangers is presented. In finned-tube coils fin side fluid is air and tube side fluid can be water, oil, glycol water solution mixture and refrigerants. The analysis and rating of coils at dry and wet operating conditions are presented. Design and the most suitable selections of coils at the given parameters and design constraints from many different coil geometries are also performed in the software. User-friendly object-oriented programming C# is applied in developing the software. The software is developed in modular basic. Six modules are developed: Heating Coils, Cooling Coils, Condenser Coils, Steam Coils, Heat Recovery Coils and Evaporator (DX) Coils. REFPROP is also integrated in the software and all fluids’ thermal and transport properties are obtained from REFPROP. Heat transfer and pressure drop correlations available from literature are evaluated with recommendations. Simulated results are verified against experimental results.


Author(s):  
Jacqueline Copetti ◽  
Mario Henrique Macagnan ◽  
Anselmo Goulart Gonçalves ◽  
Desirê Lara Mehringer Kreische
Keyword(s):  

2019 ◽  
Author(s):  
Chem Int

Model was developed for the prediction of polarization characteristics in a dielectric material exhibiting piezoelectricity and electrostriction based on mathematical equations and MATLAB computer simulation software. The model was developed based on equations of polarization and piezoelectric constitutive law and the functional coefficient of Lead Zirconate Titanate (PZT) crystal material used was 2.3×10-6 m (thickness), the model further allows the input of basic material and calculation of parameters of applied voltage levels, applied stress, pressure, dielectric material properties and so on, to generate the polarization curve, strain curve and the expected deformation change in the material length charts. The mathematical model revealed that an application of 5 volts across the terminals of a 2.3×10-6 m thick dielectric material (PZT) predicted a 1.95×10-9 m change in length of the material, which indicates piezoelectric properties. Both polarization and electric field curve as well as strain and voltage curve were also generated and the result revealed a linear proportionality of the compared parameters, indicating a resultant increase in the electric field yields higher polarization of the dielectric materials atmosphere.


2006 ◽  
Vol 29 (7) ◽  
pp. 1138-1143 ◽  
Author(s):  
Branislav M. Jacimovic ◽  
Srbislav B. Genic ◽  
Boris R. Latinovic

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