scholarly journals Research on High-Pressure Hydrogen Pre-Cooling Based on CFD Technology in Fast Filling Process

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2208
Author(s):  
Sen Li ◽  
Jinxing Guo ◽  
Xin Lv ◽  
Teng Deng ◽  
Bo Cao ◽  
...  
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Transfer Process ◽  
Volume Fraction ◽  
Cooling System ◽  
Operating Cost ◽  
Heat Transfer Process ◽  
Inlet Temperature ◽  
Filling Process ◽  
Pressure Hydrogen

In the fast filling process, in order to control the temperature of the vehicle-mounted storage tank not to exceed the upper limit of 85 °C, it is an effective method to add a hydrogen pre-cooling system upstream of the hydrogenation machine. In this paper, Fluent is used to simulate the heat transfer process of high-pressure hydrogen in a shell-and-tube heat exchanger and the phase change process of refrigerant R23. The accuracy of the model is proven by a comparison with the data in the references. Using this model, the temperature field and gas volume fraction in the heat transfer process are obtained, which is helpful to analyze the heat transfer mechanism. At the same time, the influence of hydrogen inlet temperature, hydrogen inlet pressure, and refrigerant flow rate on the refrigeration performance was studied. The current work shows that the model can be used to determine the best working parameters in the pre-cooling process and reduce the operating cost of the hydrogen refueling station.

Heat transfer process of R600a spray cooling system

2015 ◽  
Vol 27 (7) ◽  
pp. 71001
Author(s):  
徐洪波 Xu Hongbo ◽  
钱春潮 Qian Chunchao ◽  
邵双全 Shao Shuangquan ◽  
田长青 Tian Changqing ◽  
司春强 Si Chunqiang
Keyword(s):  
Heat Transfer ◽  
Transfer Process ◽  
Cooling System ◽  
Spray Cooling ◽  
Heat Transfer Process

Brayton Cycle Optimization

1997 ◽  
Author(s):  
Sushanta K. Mitra ◽  
Achintya Mukhopadhaya
Keyword(s):  
Heat Transfer ◽  
Transfer Process ◽  
Power Output ◽  
Practical Importance ◽  
Heat Transfer Process ◽  
Working Fluid ◽  
Operating Parameters ◽  
Inlet Temperature ◽  
Brayton Cycle ◽  
The Ideal

The Brayton Cycle is the ideal cycle for simple gas turbine applications. The heat transfer process in such a cycle is of practical importance as far as power output is considered. The present work focusses on the power output from an ideally reversible Brayton cycle and criteria for optimum power based on its operating parameters like the specific heat of hot and cold fluids, working fluid and heater inlet temperature is discussed here.

Effect of nanofluids on heat transfer and cooling system of the photovoltaic/thermal performance

2019 ◽  
Vol 29 (6) ◽  
pp. 1920-1946 ◽  
Author(s):  
Rehena Nasrin ◽  
Md. Hasanuzzaman ◽  
N.A. Rahim
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Thermal Performance ◽  
Thermal Efficiency ◽  
Volume Fraction ◽  
Cooling System ◽  
Solid Volume Fraction ◽  
Inlet Temperature ◽  
Content Type ◽  
Water Based

PurposeEffective cooling is one of the challenges for photovoltaic thermal (PVT) systems to maintain the PV operating temperature. One of the best ways to enhance rate of heat transfer of the PVT system is using advanced working fluids such as nanofluids. The purpose of this research is to develop a numerical model for designing different form of thermal collector systems with different materials. It is concluded that PVT system operated by nanofluid is more effective than water-based PVT system.Design/methodology/approachIn this research, a three-dimensional numerical model of PVT with new baffle-based thermal collector system has been developed and solved using finite element method-based COMSOL Multyphysics software. Water-based different nanofluids (Ag, Cu, Al, etc.), various solid volume fractions up to 3 per cent and variation of inlet temperature (20-40°C) have been applied to obtain high thermal efficiency of this system.FindingsThe numerical results show that increasing solid volume fraction increases the thermal performance of PVT system operated by nanofluids, and optimum solid concentration is 2 per cent. The thermal efficiency is enhanced approximately by 7.49, 7.08 and 4.97 per cent for PVT system operated by water/Ag, water/Cu and water/Al nanofluids, respectively, compared to water. The extracted thermal energy from the PVT system decreases by 53.13, 52.69, 42.37 and 38.99 W for water, water/Al, water/Cu and water/Ag nanofluids, respectively, due to each 1°C increase in inlet temperature. The heat transfer rate from heat exchanger to cooling fluid enhances by about 18.43, 27.45 and 31.37 per cent for the PVT system operated by water/Al, water/Cu, water/Ag, respectively, compared to water.Originality/valueThis study is original and is not being considered for publication elsewhere. This is also not currently under review with any other journal.

scholarly journals ANALYSIS OF DETERMINING CRITICAL COMPONENTS USING FMECA METHOD IN SEAWATER PUMP OF DIESEL GENERATOR CATERPILLAR 3412

JOURNAL ASRO ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 124
Author(s):  
Saiful Hasan ◽  
Erpan Sahiri ◽  
Suprayitno Suprayitno ◽  
Endin Tri Hartanto
Keyword(s):  
Heat Transfer ◽  
Transfer Process ◽  
Preventive Maintenance ◽  
Cooling System ◽  
Heat Transfer Process ◽  
Failure Model ◽  
Diesel Generator ◽  
Component Reliability ◽  
Operational Conditions ◽  
Critical Components

The seawater pump on the Caterpillar 3412 Diesel Generator is one of the important component to make the Diesel generator can work well. This section serves to circulate seawater for the heat transfer process. The seawater pump is part of a cooling system of the engine which keeps the engine temperature from being too overheat. Seawater pumps with continuous operational conditions, resulting in reduced component reliability. This study applies the FMECA method to identify opportunities for failure at the seawater pump. From the calculation of FMECA, it is obtained an assessment of the level of risk from a failure model that can give priority scale to preventive maintenance that can be done in the future. FMECA analysis of 27 components in seawater pump on the Diesel Generator, found 7 components that had RPN values above the average. The following are the 4 components with the highest RPN value, namely Shaft (7C-3493) RPN value 420,44; Key (175-6716) RPN value 300,31; Bearing Inner (4M-6107) RPN value 285 and Bearing Roller (3N-8463) RPN value 253,13. Components that have high RPN values require more attention, such as routine checks and periodic maintenance.Keyword: Seawater pump, Caterpillar 3412 Diesel Generator, FMECA, RPN.

Comprehensive Reduction of Thermal Resistance in Air Cooled Condensers

2015 ◽  
Author(s):  
Ahmad Saleh ◽  
Jayanta Kapat
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Heat Pipe ◽  
Transfer Process ◽  
Cooling System ◽  
Ambient Air ◽  
Heat Transfer Process ◽  
Air Cooling ◽  
Total Thermal Resistance ◽  
Fin Efficiency

Restriction on water consumption is becoming an increasing problem for the power generation industry. As an alternative both to once-through cooling and to surface condenser/wet-cooling tower combination, utility companies and equipment manufacturers are considering, and even implementing, air-cooled condenser (ACC). However, the industry is quite reluctant to switch over to ACC for three important reasons: (a) lower power output, (b) higher capital cost, and (c) larger physical foot-print, all because of the same reason — it is not as efficient to transfer heat from condensing steam to air as it is to transfer to water. In other words, overall thermal resistance from condensing steam to the ambient air is significantly higher than to cooling water. To get a clear and full understanding of the heat transfer process occur in air-cooling condenser, Detailed mathematical equations were derived to model the heat transfer process through the fined-tubes of the ACC. The total thermal resistance model was analyzed and investigated to identify the design components with highest affect in the process. The paper proposes a viable cooling system based on novel heat pipe technology which addresses these problems. This technology employs boiling as the means to store and transfer heat energy. A detailed mathematical set of equations was derived to model the heat pipe thermal resistance. A comparison of the heat transfer performances of the ACC technology and the proposed method is presented. The proposed cooling system suggests a solution for each of the three components of the thermal resistance, the super-hydrophobic coating of the steam ducts internal surfaces increased the condensing heat transfer rate by an order of magnitude, the proposed design of the heat pipes improved the external heat transfer, and the installation mechanism improves the fin efficiency by eliminating the contact resistance between steam duct and the heat pipe.

Experimental investigation of Silver / Water nanofluid heat transfer in car radiator

2021 ◽  
Vol 15 (1) ◽  
pp. 7743-7753
Author(s):  
H. T. Jarrah ◽  
S. S. Mohtasebi ◽  
E. Ettefaghi ◽  
F. Jaliliantabar
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Performance ◽  
Volume Fraction ◽  
Cooling System ◽  
Pure Water ◽  
Research Work ◽  
Inlet Temperature ◽  
Transfer Performance ◽  
Heat Transfer Efficiency ◽  
Low Concentrations

Currently available fluids for heat transfer including refrigerants, water, ethylene glycol mixture, etc., have been widely exploited in various fields, especially in automobile cooling systems, for many years. However, these fluids possess poor heat transfer capability which means that to achieve acceptable heat transfer activity, high compactness and effectiveness of heat transfer systems are essential. This research work concentrates on preparation and use of water based Silver containing nanofluids in automobile cooling system. Nanoparticles volume fraction, fluid inlet temperature, coolant and air Reynolds numbers were optimized so that the heat transfer performance of the car radiator system was totally improved. It was found that increasing these parameters leads to enhancement of the heat transfer performance. In the best condition, the Ag/water nanofluids with low concentrations could amend heat transfer efficiency up to 30.2% in comparison to pure water.

A Hybrid Modeling Approach for Characterization and Simulation of Cryogenic Machining of Ti–6Al–4V Alloy

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Bin Shi ◽  
Ahmed Elsayed ◽  
Ahmed Damir ◽  
Helmi Attia ◽  
Rachid M'Saoubi
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Tool Wear ◽  
Transfer Process ◽  
Volume Fraction ◽  
Heat Transfer Process ◽  
Hybrid Modeling ◽  
Fe Model ◽  
Cryogenic Machining ◽  
Modeling Approach

A hybrid modeling approach based on computational fluid dynamics (CFD) and finite element method (FEM) is presented to simulate and study cryogenic machining (CM) of Ti–6Al–4V alloy. CFD analysis was carried out to study the characteristics of the fluid flow and heat transfer process of liquid nitrogen (LN2) jet used as a coolant in turning operation. The velocity, turbulence, gas volume fraction, and temperature of the impingement jet were investigated. Based on the analysis results, the coefficient of heat transfer (CHT) between the LN2 and cutting tool/insert was obtained and used in the FEM analysis to model the heat transfer process between the LN2 and the tool/chip/workpiece. A three-dimensional (3D) finite element (FE) model was developed to simulate a real CM operation. CM tests were carried out to validate the 3D FE model by comparing cutting forces and chip temperature. To evaluate LN2 cooling effect on tool temperature and tool wear, a two-dimensional (2D) FE model was developed for steady-state thermal analysis of cryogenic and dry machining. Based on the predicted temperatures, the tool wear was estimated, showing that LN2 cooling can significantly improve tool life.

scholarly journals MODELING THE HEAT TRANSFER PROCESS IN REFRIGERATION UNITS USED IN THE OIL INDUSTRY

2019 ◽  
Vol 6 ◽  
pp. 57-62
Author(s):  
Ibrahim Abulfaz Gabibov ◽  
Rabiya Seydulla Nadjafkulieva ◽  
Sevinj Malik Abasova
Keyword(s):  
Heat Transfer ◽  
Transfer Process ◽  
Cooling System ◽  
High Heat ◽  
Heat Transfer Process ◽  
Gas Production ◽  
Pipeline System ◽  
Processing Plant ◽  
Associated Petroleum Gas ◽  
High Heat Transfer

Currently, the main volume of associated petroleum gas production in Azerbaijan is carried out at offshore fields. About 30 % of this volume is used for SOCAR’s own technological needs of the oil company (to maintain the level of oil production). And the rest are transported to onshore facilities and further for processing to a gas processing plant. Subsequently, dry and purified gas is sent through a gas pipeline system for use by the population, or to a network of trunk pipelines for further export. When gas is transferred to the gas lift system and ashore, it is compressed in compressors, as a result of which the temperature of the working agent rises. The latter dramatically reduces the level of operational safety of the entire process. Based on the foregoing, ensuring the required gas quality at the outlet of the compressor unit is an important and urgent task. Currently used in the gas cooling system, shell-and-tube type refrigeration units have several advantages: high heat transfer coefficient, operability in low and high pressure modes, simplicity of design and service. Along with this, these units are distinguished by large dimensions and high metal consumption, noise effect, vibration, etc. A new design of a heat exchanger for cooling associated petroleum gas at the outlet of gas motor compressors is proposed. Based on the modeling of the heat transfer process, mathematical models have been obtained that make it possible to adequately evaluate the cooling process in the proposed refrigeration device.

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