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M A Akhavanbehabadi - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation of heat transfer during flow condensation of hc r600a based nano Refrigerant inside a horizontal u shaped tube
International Journal of Thermal Sciences, 2019Co-Authors: M M Ahmadpour, M A AkhavanbehabadiAbstract:Abstract This experimental study investigates the effect of MWCNT (multi-walled carbon nanotube) nanoparticles on condensation heat transfer characteristics of R600a/oil mixture inside a horizontal U-shaped tube. The experiments are organized in three parts: (i) Pure Refrigerant flow, (ii) Refrigerant-oil mixture flow with oil mass fraction of 1%, and (iii) R600a/oil/MWCNT nano-Refrigerant flow with nanoparticle mass fractions of 0.1, 0.2, and 0.3%. The condenser consists of two 135 cm straight sections and a U-bend with the inner diameter of 8.7 mm and the curve ratio of 21 installed in a 6 cm polyethylene shell. The tests are carried out in a wide range of operating conditions, including condensation pressure of 510–630 kPa, mass velocity of 140, 187, 233, and 280 kg/m2s, and vapor quality of 0.04–0.75. The results show that at low vapor quality, adding lubricating oil into the Refrigerant improves the heat transfer coefficient of the mixture in comparison to the Pure Refrigerant, while this trend is reversed at medium and high vapor quality due to the lubricating oil impact on the condensation liquid film. In addition, the nano-Refrigerant flow heat transfer coefficient increases with mass velocity while there is a critical vapor quality in which the local coefficient becomes maximum. Based on the results, using 0.3% of MWCNT causes maximum local heat transfer enhancement up to 68.2%, in comparison to the Pure Refrigerant. Heat transfer enhancement by adding nanoparticles is more effective at low and intermediate vapor quality.
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experimental investigation of condensation heat transfer of r600a poe cuo nano Refrigerant in flattened tubes
International Communications in Heat and Mass Transfer, 2017Co-Authors: Babak Ghorbani, M A Akhavanbehabadi, Sasan Ebrahimi, Krishna VijayaraghavanAbstract:Abstract In this study, the effect of addition of copper oxide nanoparticles on condensing heat transfer coefficient of R600a Refrigerant flowing in a flat tube condenser has been investigated experimentally. The test setup consists of a pump, condenser test, second condenser, evaporator, heaters, and flow meter. The validation of the study was done by comparing the obtained condensation heat transfer coefficients with different empirical correlations in the literature. Different fluids including Pure R600a, R600a-oil with Polyester oil (POE) mass percentage of 1%, and three R600a-oil-nanoparticle mixtures with mass percentages of 0.5%, 1%, and 1.5% were studied experimentally. It was shown that adding nanoparticles will result in 4.1%, 8.11%, and 13.7% average increase in condensing heat transfer coefficient with respect to the R600a-oil mixture. The greatest amount of increase was reported for the weight fraction of 1.5%, where it was observed that the condensing heat transfer coefficient for the mixture passing through the flattened tube is averagely 109.3% higher than its corresponding value for the Pure Refrigerant flowing in the round tube with the same mass flux. It was also found that an increase in mass flux resulted in an increase the heat transfer coefficient at all vapor qualities.
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effect of lubricating oil on flow boiling characteristics of r 600a oil inside a horizontal smooth tube
Applied Thermal Engineering, 2015Co-Authors: Mohammadreza Momenifar, M A Akhavanbehabadi, M Nasr, Pedram HanafizadehAbstract:Abstract The aim of the present study is to experimentally investigate the effect of oil on flow boiling of R-600a as a hydrocarbon Refrigerant inside a horizontal smooth tube. In order to study the effect of oil on the flow boiling of R-600a, a well instrumented apparatus was designed, fabricated and installed. The experimental conditions of this study include nominal oil concentrations from 0% to 2.5%, mass velocities in range of 130–380 kg/m2s, inlet vapor qualities from 0.05 to 0.77 and heat fluxes from 10 to 28 kW/m2which were conducted in a copper test tube with the inner diameter of 8.7 mm. Several parameters affecting the heat transfer coefficient and pressure drop of Refrigerant–oil mixture, such as oil concentration, mass flux and vapor quality were investigated. The comparison between two-phase pressure drop for Pure Refrigerant and the Refrigerant oil mixture reveals that pressure drop increases with the increase of oil concentration in all ranges of vapor quality and mass velocities. However, heat transfer coefficients tend to increase at low vapor qualities and decrease at the middle and high vapor qualities due to presence of oil.
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experimental study on heat transfer characteristics of r600a poe cuo nano Refrigerant flow condensation
Experimental Thermal and Fluid Science, 2015Co-Authors: M A Akhavanbehabadi, Milad Darzi, Mohammadkazem Sadoughi, M FakoorpakdamanAbstract:Abstract An experimental study is carried out on heat transfer characteristics of a nano-Refrigerant flow during condensation inside a horizontal smooth tube. Experiments are conducted for three different working fluid types including: (i) Pure Refrigerant (R600a); (ii) Refrigerant/lubricant (R600a/oil); and (iii) nano-Refrigerant: Refrigerant/lubricant/nanoparticles (R600a/oil/CuO). Polyolester oil (POE) is utilized as the lubricant in the two latter cases. In addition, nano-Refrigerants (R600a/oil/CuO) are prepared by dispersing CuO nanoparticles with different mass fractions of 0.5%, 1% and 1.5% in the baseline mixture (R600a/oil). The implemented experiments covered a wide range of variables including: (i) mass fluxes from 154.8 to 265.4 kg/m2/s; (ii) vapor qualities between 10% and 80%; (iii) heat flux from 17 to 20 kW/m2; and (iv) condensation pressure from 5.1 to 6.2 bar. It is shown that significant heat transfer enhancement is achieved by adding nanoparticles to the baseline mixture and Pure Refrigerant. The maximum heat transfer augmentation was observed for nano-Refrigerant with 1.5% mass fraction; 83% higher heat transfer rate compared to Pure-Refrigerant fluid flow at the same experimental conditions.
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experimental investigation of flow boiling heat transfer of r 600a oil cuo in a plain horizontal tube
Experimental Thermal and Fluid Science, 2014Co-Authors: M A Akhavanbehabadi, M Nasr, S BaqeriAbstract:Abstract The aim of this paper is to experimentally investigate the effect of CuO nanoparticles on flow boiling of R-600a/Polyester mixture (99/1) inside a horizontal smooth tube. The experimental conditions of this study include mass velocities from 50 to 400 kg/m 2 s, inlet vapor qualities from 0 to 0.9, heat fluxes from 3 to 8 kW/m 2 and mass fractions of CuO nanoparticles from 0 to 1.5 wt%. The well instrumented experimental apparatus including pump, flow meter, preheater, test evaporator, by-pass and condenser was designed, fabricated and installed in order to measure the experimental data on flow boiling heat transfer of Refrigerant, Refrigerant oil and Refrigerant nanooil. Ultrasonic instrument was used to approach to the well dispersed nanooil and then the nanooil was injected with a syringe into the Pure Refrigerant through the cycle. The solutions were mixed by running them through the system at a high velocity for approximately 3 h. The results show that, nanoparticles cause a maximum heat transfer enhancement up to 63% relative to heat transfer coefficient of R-600a/oil without nanoparticles.
Eder Dutra De ,resende - One of the best experts on this subject based on the ideXlab platform.
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Tecnicas de modelagem, simulação e otimização de processos de refrigeração e de congelamento
[s.n.], 2018Co-Authors: Eder Dutra De ,resendeAbstract:Orientador: Maria Regina Wolf MacielTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia QuimicaResumo: Neste trabalho são desenvolvidas a modelagem, a simulação e a otimização de um sistema de refrigeração aplicado para o congelamento de produtos alimentícios. O estudo é dividido em duas etapas: a primeira parte procura identificar os fenômenos termo dinâmicos típicos de uma planta de refrigeração, juntamente com o desenvolvimento de uma metodologia de simulação e de otimização termo econômica da planta. A segunda parte identifica o comportamento termodinâmico da carga térmica de um equipamento de congelamento, juntamente com o desenvolvimento de uma metodologia de otimização do perfil de temperatura do produto. Inicialmente é feita a modelagem das propriedades termo dinâmicas do fluido Refrigerante, compreendendo as regiões de líquido subresfriado até a região de vapor superaquecido, possibilitando um estudo mais criterioso do perfil de temperatura do fluido no interior do circuito de refrigeração. O algoritmo básico de simulação destas transformações termodinâmicas apresenta características de versatilidade que favorecem o desenvolvimento de novas configurações da planta de refrigeração. O modelo de simulação do circuito de refrigeração é posteriormente desenvolvido com o objetivo de identificar o comportamento tennodinâmico do sistema de refrigeração operando com fluidos Refrigerantes puros e também com misturas não-azeotrópicas que apresentam um alto desempenho tennodinâmico e são consideradas como fluidos não agressivos ao meio ambiente. Esta metodologia de simulação possibilita a análise do comportamento tennodinâmico do sistema, mantido sob diferentes condições de operação de regime de estado estacionário. A simulação do circuito termodinâmico possibilita a modelagem das unidades básicas da planta de refrigeração através da inserção de modelos fisicos típicos que representam os trocadores de calor, o compressor e a válvula de expansão. Este modelo da planta de refrigeração foi denominado INCICLO, sendo caracterizado pela sensível capacidade de identificação do desempenho termo dinâmico do fluido Refrigerante que opera no sistema, possibilitando, ainda, o dimensionamento das unidades do sistema, bem como a análise do consumo de energia da planta. Além disso, desenvolve-se um estudo de otimização do consumo de energia da planta de refrigeração, levando em consideração os fatores de custo das unidades da planta e o consumo de energia do sistema, procurando minimizar as irreversibilidades inerentes da operação do sistema de refrigeração. Finalmente, apresenta-se um estudo de otimização do perfil de carga térmica de um sistema de congelamento de alimentos procurando identificar as condições de operação do equipamento que favorecem a manutenção dos atributos de qualidade do produto congelado. Este procedimento é considerado de importância fundamental para a identificação das variáveis operacionais ótimas da planta de refrigeraçãoAbstract: In this work the modelling, the simulation and the optimisation of a refrigeration system applied to food freezing processes are developed. The study is divided in two stages: the first part tries to identify the typical thermodynamic behaviour of a refrigeration plant, together with the development of a methodology for simulation and for a thermoeconomic optimisation procedure applied to this plant. The second part identifies the thermodynamic behaviour of the thermal load of a freezing equipment, together with an optimisation methodology of the product temperature profile. Initially, the modelling of the thermodynamic properties of the Refrigerant fluid is carried out, considering the regions of the subcooling liquid up to the superheating vapour regions, providing a more detailed study of the temperature profile of the fluid inside the refrigeration cycle. The basic simulation algorithm of these thermodynamic transformations presents versatility characteristics that facilitate the development of new design configurations of the refrigeration plant. The modeI of simulation of the refrigeration cycle is developed later on with the aim of identifying the thermodynamic behaviour of the refrigeration system operating with Pure Refrigerant fluid and also with nonazeotropic mixtures, which present a high thermodynamic performance and are considered as non aggressive fluids for the environment. This simulation methodology facilitates the thermodynamic analysis of the system, maintained under different operating conditions at steady state. The simulation of the thermodynamic cycle enables the modelling of the basic units of the refrigeration plant through the use of typical physical models which represent the heat exchangers, the compressor and the expansion valve. This modeI of the refrigeration plant was named INCICLO, being characterised by its sensible capacity to identify the thermodynamic performance of the Refrigerant fluid that operates in the system, and still facilitating the sizing of the system units, as well as the analysis of the plant energy consumption. Besides, an optimisation study of the plant energy consumption was developed, taking into consideration the factors of unit costs and the energy consumption of the system, trying to minimise the irreversibilities inherent of the refrigeration processo. Finally, in this work is presented an optimisation study ofthe heat load profile applied to food freezing process, trying to identify the operating conditions of the equipment that maintain the quality attributes of the frozen product. This procedure is considered of great importance to identify the optimal operational conditions of the refrigeration plantDoutoradoDesenvolvimento de Processos QuímicosDoutor em Engenharia Químic
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Tecnicas de modelagem, simulação e otimização de processos de refrigeração e de congelamento
2017Co-Authors: Eder Dutra De ,resendeAbstract:Resumo: Neste trabalho são desenvolvidas a modelagem, a simulação e a otimização de um sistema de refrigeração aplicado para o congelamento de produtos alimentícios. O estudo é dividido em duas etapas: a primeira parte procura identificar os fenômenos termo dinâmicos típicos de uma planta de refrigeração, juntamente com o desenvolvimento de uma metodologia de simulação e de otimização termo econômica da planta. A segunda parte identifica o comportamento termodinâmico da carga térmica de um equipamento de congelamento, juntamente com o desenvolvimento de uma metodologia de otimização do perfil de temperatura do produto. Inicialmente é feita a modelagem das propriedades termo dinâmicas do fluido Refrigerante, compreendendo as regiões de líquido subresfriado até a região de vapor superaquecido, possibilitando um estudo mais criterioso do perfil de temperatura do fluido no interior do circuito de refrigeração. O algoritmo básico de simulação destas transformações termodinâmicas apresenta características de versatilidade que favorecem o desenvolvimento de novas configurações da planta de refrigeração. O modelo de simulação do circuito de refrigeração é posteriormente desenvolvido com o objetivo de identificar o comportamento tennodinâmico do sistema de refrigeração operando com fluidos Refrigerantes puros e também com misturas não-azeotrópicas que apresentam um alto desempenho tennodinâmico e são consideradas como fluidos não agressivos ao meio ambiente. Esta metodologia de simulação possibilita a análise do comportamento tennodinâmico do sistema, mantido sob diferentes condições de operação de regime de estado estacionário. A simulação do circuito termodinâmico possibilita a modelagem das unidades básicas da planta de refrigeração através da inserção de modelos fisicos típicos que representam os trocadores de calor, o compressor e a válvula de expansão. Este modelo da planta de refrigeração foi denominado INCICLO, sendo caracterizado pela sensível capacidade de identificação do desempenho termo dinâmico do fluido Refrigerante que opera no sistema, possibilitando, ainda, o dimensionamento das unidades do sistema, bem como a análise do consumo de energia da planta. Além disso, desenvolve-se um estudo de otimização do consumo de energia da planta de refrigeração, levando em consideração os fatores de custo das unidades da planta e o consumo de energia do sistema, procurando minimizar as irreversibilidades inerentes da operação do sistema de refrigeração. Finalmente, apresenta-se um estudo de otimização do perfil de carga térmica de um sistema de congelamento de alimentos procurando identificar as condições de operação do equipamento que favorecem a manutenção dos atributos de qualidade do produto congelado. Este procedimento é considerado de importância fundamental para a identificação das variáveis operacionais ótimas da planta de refrigeraçãoAbstract: In this work the modelling, the simulation and the optimisation of a refrigeration system applied to food freezing processes are developed. The study is divided in two stages: the first part tries to identify the typical thermodynamic behaviour of a refrigeration plant, together with the development of a methodology for simulation and for a thermoeconomic optimisation procedure applied to this plant. The second part identifies the thermodynamic behaviour of the thermal load of a freezing equipment, together with an optimisation methodology of the product temperature profile. Initially, the modelling of the thermodynamic properties of the Refrigerant fluid is carried out, considering the regions of the subcooling liquid up to the superheating vapour regions, providing a more detailed study of the temperature profile of the fluid inside the refrigeration cycle. The basic simulation algorithm of these thermodynamic transformations presents versatility characteristics that facilitate the development of new design configurations of the refrigeration plant. The modeI of simulation of the refrigeration cycle is developed later on with the aim of identifying the thermodynamic behaviour of the refrigeration system operating with Pure Refrigerant fluid and also with nonazeotropic mixtures, which present a high thermodynamic performance and are considered as non aggressive fluids for the environment. This simulation methodology facilitates the thermodynamic analysis of the system, maintained under different operating conditions at steady state. The simulation of the thermodynamic cycle enables the modelling of the basic units of the refrigeration plant through the use of typical physical models which represent the heat exchangers, the compressor and the expansion valve. This modeI of the refrigeration plant was named INCICLO, being characterised by its sensible capacity to identify the thermodynamic performance of the Refrigerant fluid that operates in the system, and still facilitating the sizing of the system units, as well as the analysis of the plant energy consumption. Besides, an optimisation study of the plant energy consumption was developed, taking into consideration the factors of unit costs and the energy consumption of the system, trying to minimise the irreversibilities inherent of the refrigeration processo. Finally, in this work is presented an optimisation study ofthe heat load profile applied to food freezing process, trying to identify the operating conditions of the equipment that maintain the quality attributes of the frozen product. This procedure is considered of great importance to identify the optimal operational conditions of the refrigeration plan
M Nasr - One of the best experts on this subject based on the ideXlab platform.
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effect of lubricating oil on flow boiling characteristics of r 600a oil inside a horizontal smooth tube
Applied Thermal Engineering, 2015Co-Authors: Mohammadreza Momenifar, M A Akhavanbehabadi, M Nasr, Pedram HanafizadehAbstract:Abstract The aim of the present study is to experimentally investigate the effect of oil on flow boiling of R-600a as a hydrocarbon Refrigerant inside a horizontal smooth tube. In order to study the effect of oil on the flow boiling of R-600a, a well instrumented apparatus was designed, fabricated and installed. The experimental conditions of this study include nominal oil concentrations from 0% to 2.5%, mass velocities in range of 130–380 kg/m2s, inlet vapor qualities from 0.05 to 0.77 and heat fluxes from 10 to 28 kW/m2which were conducted in a copper test tube with the inner diameter of 8.7 mm. Several parameters affecting the heat transfer coefficient and pressure drop of Refrigerant–oil mixture, such as oil concentration, mass flux and vapor quality were investigated. The comparison between two-phase pressure drop for Pure Refrigerant and the Refrigerant oil mixture reveals that pressure drop increases with the increase of oil concentration in all ranges of vapor quality and mass velocities. However, heat transfer coefficients tend to increase at low vapor qualities and decrease at the middle and high vapor qualities due to presence of oil.
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experimental investigation of flow boiling heat transfer of r 600a oil cuo in a plain horizontal tube
Experimental Thermal and Fluid Science, 2014Co-Authors: M A Akhavanbehabadi, M Nasr, S BaqeriAbstract:Abstract The aim of this paper is to experimentally investigate the effect of CuO nanoparticles on flow boiling of R-600a/Polyester mixture (99/1) inside a horizontal smooth tube. The experimental conditions of this study include mass velocities from 50 to 400 kg/m 2 s, inlet vapor qualities from 0 to 0.9, heat fluxes from 3 to 8 kW/m 2 and mass fractions of CuO nanoparticles from 0 to 1.5 wt%. The well instrumented experimental apparatus including pump, flow meter, preheater, test evaporator, by-pass and condenser was designed, fabricated and installed in order to measure the experimental data on flow boiling heat transfer of Refrigerant, Refrigerant oil and Refrigerant nanooil. Ultrasonic instrument was used to approach to the well dispersed nanooil and then the nanooil was injected with a syringe into the Pure Refrigerant through the cycle. The solutions were mixed by running them through the system at a high velocity for approximately 3 h. The results show that, nanoparticles cause a maximum heat transfer enhancement up to 63% relative to heat transfer coefficient of R-600a/oil without nanoparticles.
M Fakoorpakdaman - One of the best experts on this subject based on the ideXlab platform.
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experimental study on heat transfer characteristics of r600a poe cuo nano Refrigerant flow condensation
Experimental Thermal and Fluid Science, 2015Co-Authors: M A Akhavanbehabadi, Milad Darzi, Mohammadkazem Sadoughi, M FakoorpakdamanAbstract:Abstract An experimental study is carried out on heat transfer characteristics of a nano-Refrigerant flow during condensation inside a horizontal smooth tube. Experiments are conducted for three different working fluid types including: (i) Pure Refrigerant (R600a); (ii) Refrigerant/lubricant (R600a/oil); and (iii) nano-Refrigerant: Refrigerant/lubricant/nanoparticles (R600a/oil/CuO). Polyolester oil (POE) is utilized as the lubricant in the two latter cases. In addition, nano-Refrigerants (R600a/oil/CuO) are prepared by dispersing CuO nanoparticles with different mass fractions of 0.5%, 1% and 1.5% in the baseline mixture (R600a/oil). The implemented experiments covered a wide range of variables including: (i) mass fluxes from 154.8 to 265.4 kg/m2/s; (ii) vapor qualities between 10% and 80%; (iii) heat flux from 17 to 20 kW/m2; and (iv) condensation pressure from 5.1 to 6.2 bar. It is shown that significant heat transfer enhancement is achieved by adding nanoparticles to the baseline mixture and Pure Refrigerant. The maximum heat transfer augmentation was observed for nano-Refrigerant with 1.5% mass fraction; 83% higher heat transfer rate compared to Pure-Refrigerant fluid flow at the same experimental conditions.
S Baqeri - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation of flow boiling heat transfer of r 600a oil cuo in a plain horizontal tube
Experimental Thermal and Fluid Science, 2014Co-Authors: M A Akhavanbehabadi, M Nasr, S BaqeriAbstract:Abstract The aim of this paper is to experimentally investigate the effect of CuO nanoparticles on flow boiling of R-600a/Polyester mixture (99/1) inside a horizontal smooth tube. The experimental conditions of this study include mass velocities from 50 to 400 kg/m 2 s, inlet vapor qualities from 0 to 0.9, heat fluxes from 3 to 8 kW/m 2 and mass fractions of CuO nanoparticles from 0 to 1.5 wt%. The well instrumented experimental apparatus including pump, flow meter, preheater, test evaporator, by-pass and condenser was designed, fabricated and installed in order to measure the experimental data on flow boiling heat transfer of Refrigerant, Refrigerant oil and Refrigerant nanooil. Ultrasonic instrument was used to approach to the well dispersed nanooil and then the nanooil was injected with a syringe into the Pure Refrigerant through the cycle. The solutions were mixed by running them through the system at a high velocity for approximately 3 h. The results show that, nanoparticles cause a maximum heat transfer enhancement up to 63% relative to heat transfer coefficient of R-600a/oil without nanoparticles.
