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Gas/liquid Injection (liquid + injection)

Distribution by Scientific Domains

Polymers and Materials Science	28%

Selected Abstracts

Two-phase flow convective condensation of refrigerant mixtures under gas/liquid injection

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 15 2005
Samuel M. Sami
Abstract The influence of gas/liquid injection on two-phase flow condensation heat transfer characteristics of some refrigerant mixtures in horizontal enhanced surface tubing is presented. Correlations were proposed to predict the impact of the gas/liquid injection on the heat transfer characteristics such as average heat transfer coefficient of R-507, R-404A, R-410A, and R-407C in two-phase flow condensation inside enhanced surface tubing. The data also revealed that gas, liquid and gas/liquid injection is beneficial at certain gas/liquid injection ratios to the heat transfer coefficient depending upon the Reynolds number and the condensation point of the refrigerant mixtures in question. It was also evident that the proposed condensation correlations and the experimental data were applicable to the entire heat and mass flux, investigated in the present study under gas/liquid injection conditions. The deviation between the experimental and predicted under gas/liquid injection were less than ± 10, for the majority of data. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Behaviour of refrigerant mixtures with gas/liquid injection

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 14 2003
Samuel M. Sami
Abstract In this paper, the impact of gas/liquid injection on the behaviour of new alternative refrigerant mixtures such as; R-410A, R-507, R-407C, and R-404A are discussed, analysed and presented. The test results were obtained using an air,source heat pump set up with enhanced surface tubing heat exchanger under various gas/liquid injection ratios. Performance tests were conducted according to the ARI/ASHRAE Standards. The performance data demonstrated that as gas/liquid injection increases compressor head pressure and discharge temperature decrease and this has a positive effect in protecting the compressor. The effect of gas/liquid injection on mixture behaviour varies from mixture to another depending upon the mixture composition. Furthermore, hot gas injection appears to have a significant and positive influence on the COP. The performance of refrigerants R-407C and R-404A has been enhanced with 5% gas injection and mix of gas and liquid 5% injection, respectively. The data presented in these figures also show that other hot gas injection ratios and gas/liquid mix degrade the heat exchanger performance. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Study of liquid injection impact on the performance of new refrigerant mixtures

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 2 2003
Samuel M. Sami
Abstract In this paper, the test results of liquid injection impact on the performance of new alternative refrigerant mixtures such as: R-410A, R-507, R-407C and R-404A are discussed, analysed and presented. The test results were obtained using an air-source heat pump set-up with enhanced surface tubing under various liquid injection ratios. Performance tests were conducted according to the ARI/ASHRAE standards. The performance data demonstrated that as liquid injection ratio increases, compressor head pressure and discharge temperature decrease. This has a positive effect in protecting the compressor. The effect of liquid injection on mixture behaviour varies from one mixture to another depending upon the mixture's composition. Furthermore, liquid injection appears to have a significant influence on R-410A behaviour compared to the other mixtures in question. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Diamond Growth on a Si Substrate With Ceramic Interlayers

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2007
Y. S. Li
Deposition of diamond films on Si substrates precoated with a series of ceramic intermediate layers was examined. The interlayers containing SiC, SiNx, SiCN, TiSiN, and TiAlSiN were prepared by a liquid injection plasma-enhanced chemical vapor deposition (PECVD) method using alkoxide solution precursors. The subsequent diamond synthesis on these coatings was carried out by microwave plasma-assisted CVD (MPCVD) using a H2,1%CH4 mixture. A higher nucleation density of diamond was obtained on these intermediate layers than on the as-polished Si wafer, along with a nonuniform surface distribution of diamond. Diamond powder scratching pretreatment of these interlayers enhanced the nucleation density and promoted the formation of fully uniform diamond films. Particularly, nanocrystalline diamond films were directly generated on TiSiN and TiAlSiN layers under an identical deposition condition that had favored the formation of microcrystalline diamond films on Si wafers and the Si(C,N) interlayers. The mechanism for this difference is attributed primarily to a higher amount of residual amorphous carbon in TiSiN and TiAlSiN layers than that inside Si(C,N) layers. [source]

Growth and Characterization of Ti-Ta-O Thin Films on Si Substrates by Liquid Injection MOCVD for High- k Applications from Modified Titanium and Tantalum Precursors,

CHEMICAL VAPOR DEPOSITION, Issue 4-6 2010
Anjana Devi
Abstract Titanium oxide (TiO2) and titanium-tantalum oxide (Ti-Ta-O) thin films are deposited by liquid injection (LI) metal-organic (MO) CVD using metal amide-malonate complexes, [Ti(NR2)2(dbml)2], and tantalum, [Ta(NMe2)4(dbml)] (R,=,Me, Et; dbml,=,di- tert -butylmalonato). TiO2 and Ti-Ta-O films are deposited on Si(100) in the temperature ranges 350,650,°C and 500,700,°C, respectively. The structure, morphology, and chemical composition of the films are evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), Rutherford backscattering spectroscopy (RBS), and X-ray photoelectron spectroscopy (XPS). The electrical properties of the films, namely the dielectric properties, are assessed by carrying out capacitance-voltage (C - V) measurements on metal-oxide-semiconductor (MOS) capacitor structures. [source]