Refrigerant R 134a
Mostrando 1-11 de 11 artigos, teses e dissertações.
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1. Dynamics of gas bubble growth in oil-refrigerant mixtures under isothermal depressurization
This paper proposes a numerical model to predict the growth of gaseous refrigerant bubbles in oil-refrigerant mixtures with high contents of oil subjected to isothermal depressurization. The model considers an Elementary Cell (EC) in which a spherical bubble is surrounded by a concentric and spherical liquid layer containing a finite amount of dissolved liqu
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2012-06
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2. Mathematical Modeling of the Ester Oil-Refrigerant R134a Mixture Two-Phase Flow with Foam Formation Through a Small Diameter Tube
This work presents a mathematical modeling to study the ester oil ISO VG-10-refrigerant R134a mixture two-phase flow with foam formation through a 3.22 mm ID tube. Based on experimental visualization results, the flow is divided into three regions: a single phase flow at the inlet of the tube; an intermediary bubbly flow region; and a foam flow region at the
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2011-09
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3. Boiling of R-134a in horizontal mini tube
This work presents the results of an experimental study carried out with R-134a to characterize heat transfer and pressure drop during flow boiling in a horizontal smooth tube of 2.6 mm ID. The experimental tests included (i) heat fluxes in the range from 10 to 100 kW/m², (ii) the refrigerant mass velocities set to discrete values in the range of 240-930 kg
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2011
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4. Modeling of state and thermodynamic cycle properties of HFO-1234yf using a cubic equation of state
Thermodynamic property data including specific enthalpy, specific entropy and specific volume were generated for the new refrigerant HFO-1234yf (2,3,3,3-tetrafluoroprop-1-ene) using the well-known Peng and Robinson cubic equation of state. A general approach applicable to any fluid based on the concept of departure functions has been applied. Data for satura
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2010-12
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5. Analise do desempenho termodinamico e ambiental de um ciclo de refrigeração e proposta de uma função global de avaliação / Thermodynamic and enviromental analisys of a refrigerator cycle performance and propose of a global function evaluation
This work presents a proposal function to vapor compression refrigerator cycle performance from environmental and thermodynamic point of view. The function was developed through the statistic analysis of a refrigerator cycle computational results. The proposal function represents an evaluation indice of efficiency and environment criterions and was developed
Publicado em: 2009
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6. Analyze performance of capillary tube in small refrigeration system varying the speed compressor / Análise de desempenho do tubo capilar num sistema de refrigeração de pequeno porte com variação da velocidade do compressor
The need to reduce energy consumption in refrigeration and air conditioning is a priority for the refrigeration industry. This has encouraged the development of refrigeration systems more efficient and offer better performance. In this context, increases the importance of applying new technologies to a deeper understanding of these systems and the improvemen
Publicado em: 2009
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7. Estudo teórico-experimental da ebulição convectiva do refrigerante R-134a em tubos lisos / A theoretical and experimental study of convective boiling of refrigerant R-134a in smooth tubes
Apresenta um estudo teórico-experimental da ebulição convectiva do fluido refrigerante R-134a no interior de tubos lisos. Os parâmetros físicos disponíveis para medida foram: pressão, temperatura, vazão de refrigerante e potência de aquecimento, os quais, juntamente com o registro fotográfico, foram utilizados para caracterizar os padrões de escoa
Publicado em: 2005
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8. Evaluation of the rohsenow correlation through experimental pool boiling of halocarbon refrigerants on cylindrical surfaces
This paper reports results from an investigation on the performance of the Rohsenow's type of correlation when applied to the nucleate boiling of halocarbon refrigerants over cylindrical surfaces of different material. Experimental data for refrigerants R-11, R-123, R-12, and R-134a have been raised and fitted according to two different procedures. It has be
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2004-06
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9. SIMULAÇÃO DE UM COMPRESSOR HERMÉTICO ALTERNATIVO OPERANDO EM REGIME TRANSIENTE / SIMULATION OF A RECIPROCATING HERMETIC COMPRESSOR OPERATING IN TRANSIENT REGIME
O presente trabalho trata da simulação de um compressor hermético alternativo operando em regime transiente. O modelo desenvolvido expande, para a simulação do regime transiente, de modelos de regime permanente existentes na literatura. No presente modelo o sistema é dividido em volumes de controle (motor, compressor, muflas, câmaras de sucção e de
Publicado em: 2003
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10. Substitution-Newton-Raphson method applied to the modeling of a vapour compression refrigeration system using different representations of the thermodynamic properties of R-134a
This paper gives a detailed presentation of the Substitution-Newton-Raphson method, suitable for large sparse non-linear systems. It combines the Successive Substitution method and the Newton-Raphson method in such way as to take the best advantages of both, keeping the convergence features of the Newton-Raphson with the low requirements of memory and time o
Journal of the Brazilian Society of Mechanical Sciences. Publicado em: 2002-07
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11. EVALUATION OF THE GAS LOAD INFLUENCE ON AN AUTOMOTIVE AIR CONDITIONING SYSTEM / AVALIAÇÃO DA INFLUÊNCIA DA CARGA DE GÁS EM UM SISTEMA DE CONDICIONAMENTO DE AR AUTOMOTIVO
The modern automotive technology reaches considerable progress`s in the mechanical aspect as in the functional, with these technological advances, the biggest progress was made in the structure of the automobiles and in the air conditioning systems. Considering the importance of the use of refrigerant, the present work is developed, because the refrigerant g
Publicado em: 2002