In designing of condensers, the prediction of pressure drop is as important as the prediction of heat transfer coefficient. Modeling of two phase flow, particularly liquid – vapor flow under diabatic conditions inside a horizontal tube using CFD analysis is difficult with the available two phase models in FLUENT due to continuously changing flow patterns. In the present analysis, CFD analysis o...

The blends formed mixing hydrofluorocarbons (HFC) and hydrocarbons (HC) can be classified as semi-natural refrigerants since, by optimizing the composition, it is in principle possible to adapt basic features such as GWP, TEWI and flammability to the industrial and environmental requirements. However, the energetic efficiency must be competitive with the traditional refrigerants. To evaluate th...

Average Nusselt numbers were measured for R22, R290, R290/600a, and R32/152a undergoing evaporation and condensation in a brazed plate heat exchanger. The refrigerants experienced wavy, stratified flow at low heat and mass fluxes, 1.3 kW/m2 to 8.3 kW/m2 and 1.6 kg/m2 s to 19 kg/m 2 s, respectively. Heat transfer correlations from the literature for in-tube and channel flow of refrigerants with ...

Per Lundqvist Dr., Lars Herbe M.Sc, The Royal Institute ofTechnology, Dept. of Energy Technology, S-100 44, Stockholm, Sweden Fax: +46 8 20 30 07 Tel: +46 8 790 74 52 Email: [email protected] There are several important issues when dealing with new refrigerants in a retrofit situation. This paper is however restricted to system performance and a discussion of methods suitable to determine ...

Madeleine R. Johnson AGMC/MAEL 813 Irving Wick Drive West Newark AFB, Ohio 43057-5149 This paper describes the initial results of a refrigerant retrofit project at the Aerospace Guidance and Metrology Center (AGMC) at Newark Air Force Base, Ohio. The objective is to convert selected types of test equipment to properly operate on hydrofluorocarbon (HFC) alternative refrigerants, having no ozone ...

The Corresponding States (CS) density models for mixture proposed here, one for saturated and one for compressed liquid, are analytically similar to the pure fluid liquid density exposed in the former paper, but now with critical constants and 8,, replacing wm , as from the mixing rules. The mixing rules present two adjustable interaction coefficients for each binary pair, but they are set to u...

Halogenated natural products are frequently reported metabolites in marine seaweeds. These compounds span a range from halogenated indoles, terpenes, acetogenins, phenols, etc., to volatile halogenated hydrocarbons that are produced on a very large scale. In many cases these halogenated marine metabolites possess biological activities of pharmacological interest. Given the abundance of halogena...

This paper demonstrates the capabilities of the PFGC-MES equation of state (EOS) for calculating the thermodynamic properties in the superheated region for pure refrigerants. In addition the ability of this EOS is also tested for predicting the VLE behavior of binary mixtures. For pure compounds several properties in the superheated region are predicted. The calculated results and the experimen...

Graphyne and graphdiyne families of flat carbon (sp2/sp) networks with high degrees of π-conjunction are attracting much attention due to their promising electronic, optical, and mechanical properties. In the present investigation we have studied the structural, mechanical, electrical and optical properties of halogenated graphdiyne and graphyne. The optical spectra of pure and halog...