IMPORTANCE OF 3D VEHICLE HEAT EXCHANGER MODELING

2021 ◽  
pp. 1-10
Author(s):  
Michal Schmid ◽  
Fatih Bozkurt ◽  
Petr Pašcenko ◽  
Pavel Petržela
Keyword(s):  
Fluid Flow ◽  
Heat Exchanger ◽  
Fluid Velocity ◽  
Coolant Temperature ◽  
Inlet Temperature ◽  
Vehicle Simulation ◽  
Velocity Magnitude ◽  
Primary Fluid ◽  
The Difference ◽  
Inlet Conditions

Abstract The work demonstrates, via a comprehensive study, the necessity of using a 3D CFD approach for heat exchanger (HTX) modelling within underhood vehicle simulation. The results are presented as the difference between 1D and 3D CFD approaches with a focus on auxiliary fluid (e.g. coolant) temperature prediction as a function of primary fluid (e.g. air) inlet conditions. It has been shown that the 1D approach could significantly underpredict auxiliary fluid inlet temperature due to neglecting the spatial distribution of primary fluid velocity magnitude. The resultant difference in the auxiliary fluid flow HTX inlet temperature is presented and discussed as a function of the Uniformity Index (UI) of the primary fluid flow velocity magnitude. Additionally, the 3D HTX model's importance is demonstrated in an industrial example of full 3D underhood simulation.

scholarly journals Mathematical modeling of a multi-stream brazed aluminum plate fin heat exchanger

2010 ◽  
Vol 14 (1) ◽  
pp. 103-114 ◽  
Author(s):  
Ahmed Kohil ◽  
Hassan Farag ◽  
Mona Ossman
Keyword(s):  
Sensitivity Analysis ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Inlet Temperature ◽  
Outlet Temperature ◽  
Ethylene Plant ◽  
Inlet Flow Rate ◽  
Cold Stream ◽  
Inlet Conditions ◽  
Good Agreement

The need for small size and lightweight heat exchangers in many applications has resulted in the development of many heat transfer surfaces. This type of heat exchanger is much more compact than can be practically realized with circular tubes. In this work a steady-state mathematical model that representing one of the plate fin heat exchangers enclosed in cold box of an ethylene plant has been developed. This model could evaluate the performance of the heat exchanger by predicting the outlet temperatures of the hot and cold streams when the inlet conditions are known. The model has been validated by comparing the results with actual operating values and the results showed good agreement with the actual data. Sensitivity analysis was applied on the model to illustrate the main parameters that have the greatest influence on the model calculated results. The sensitivity analysis showed that the hot stream outlet temperature is more sensitive to cold streams inlet temperatures and less sensitive to hot stream inlet temperature and thermal resistance (fouling), while the cold stream outlet temperature is more sensitive to cold streams inlet flow rate and less sensitive to fouling.

Consideration of Uncertainties in Compact Cross-Flow Heat Exchanger Design for Gas Turbine Engine Application

2013 ◽  
Author(s):  
Randall D. Manteufel ◽  
Daniel G. Vecera
Keyword(s):  
Fluid Flow ◽  
Heat Exchanger ◽  
Gas Turbine ◽  
Flow Rate ◽  
Cross Flow ◽  
Inlet Temperature ◽  
Fluid Flow Rate ◽  
Heat Exchanger Design ◽  
Cold Fluid ◽  
Flow Heat

Recent experimental work characterized the performance of a unique cross-flow heat exchanger design for application of cooling compressor bleed air using liquid jet fuel before it is consumed in the gas turbine combustor. The proposed design has micro-channels for liquid fuel and cools air flowing in passages created using rows of intermittent fins. The design appears well suited for aircraft applications because it is compact and light-weight. A theoretical model is reported to be in good agreement with experimental measurements using air and water, thus providing a design tool to evaluate variations in the heat exchanger dimensions. This paper presents an evaluation of the heat exchanger performance with consideration of uncertainties in both model parameters and predicted results. The evaluation of the design is proposed to be reproduced by students in a thermal-fluids design class. The heat exchanger performance is reevaluated using the effectiveness–NTU approach and shown to be consistent with the method reported in the original papers. Results show that the effectiveness is low and in the range of 20 to 30% as well as the NTU which ranges from 0.25 to 0.50 when the heat capacity ratio is near unity. The thermal resistance is dominated by the hot gas convective resistance. The uncertainties attributed to fluid properties, physical dimensions, gas pressure, and cold fluid flow rate are less significant when compared to uncertainties associated with hot fluid flow rate, hot fluid inlet temperature, cold fluid inlet temperature, and convective correlation for gas over a finned surface. The model shows which heat transfer mechanisms are most important in the performance of the heat exchanger.

scholarly journals A New Approach to Calculate the Velocity of Interdendritic Fluid Flow during Solidification Using Etched Surface Height of Actual Metal Ingot

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 927
Author(s):  
Zibing Hou ◽  
Zhiqiang Peng ◽  
Qian Liu ◽  
Zhongao Guo ◽  
Hongbiao Dong
Keyword(s):  
Fluid Flow ◽  
Fluid Velocity ◽  
Three Dimensional ◽  
Bearing Steel ◽  
New Approach ◽  
Velocity Magnitude ◽  
Interdendritic Fluid Flow ◽  
Gcr15 Bearing Steel ◽  
Etched Surface ◽  
Calculated Velocity

Macrosegregation remains one of main defects affecting metal materials properties, which is mainly caused by interdendritic fluid flow during solidifying. However, as for controlling actual specific segregation, it is still difficult to effectively measure or simulate this kind flow instead of pure fluid flow, especially in complex casting processes of high-grade materials. Herein, a new method for obtaining velocity magnitude and direction of interdendritic fluid flow during metal solidifying is proposed from boundary layer and standard deviation obtained by measuring etched surface heights of the actual ingot and using statistical principles. Taking continuous casting bloom of GCr15 bearing steel as an example, it is indicated that the calculated velocity magnitudes under different sides and superheats can be explained by process features and, hence, solidification mechanism. The velocity magnitude and fluctuation are higher on the inner curve side and under low superheat. Meanwhile, it is found that the fluctuation extent of secondary arm spacing is more relevant with interdendritic fluid flow, although its magnitude is mainly determined by the cooling rate. Moreover, on the basis of the calculated velocity directions and magnitudes, there is a positive correlation between segregation area ratio and the effective ratio between interdendritic flow velocity and growth velocity especially in the equiaxed grain zone, which corresponds with classic macrosegregation formation theory. The above findings and comparison with other results demonstrate the validity of the new approach, which can obtain the magnitude and the direction of interdendritic fluid velocity for two or three-dimensional multiscale velocity distribution by tailoring measuring length and numbers.

scholarly journals Improving thermal performance using Al2O3-water nanofluid in a double pipe heat exchanger filling with porous medium

2020 ◽  
Vol 24 (6 Part B) ◽  
pp. 4267-4275
Author(s):  
Qusay Jasim ◽  
Noah Saleh ◽  
Adnan Hussein
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Fluid Flow ◽  
Heat Exchanger ◽  
Volume Flow ◽  
Inlet Temperature ◽  
Flow Rates ◽  
Inside Diameter ◽  
Double Pipe ◽  
Pipe Heat

A double pipe heat exchanger is significant device for many industrial applications. In this paper, an experimental study using both porous media and nanofluid to enhance heat transfer in a double pipe heat exchanger is performed. The test rig has been fabricated with inner copper pipe of 1.10 m length, 16 mm, and 14 mm outside and inside diameter, respectively. While, the outer PVC pipe is 1 m length, 31 mm, and 27 mm outside and inside diameter, respectively. The inner pipe has been filling with 3 mm diameters of steel balls porous media. The experimental tests were performed utilizing alumina nanofluid (Al2O3-water) with two volume concentrations 0.5% and 1%. The volume flow-rates are in the range of (2-5) Lpm and 10 Lpm through inner and outer pipe, respectively. It was conducted with a constant 28?C inlet temperature of cold fluid-flow inside the inner pipe and 50?C inlet temperature of hot fluid-flow inside the outer pipe. Results indicated that the heat transfer enhanced as nanofluid volume concentrations and volume flow-rates increase. It was observed that effectiveness increases as increase of flow-rate and nanofluid concentrations.

Investigation and Improvement of Thermal Efficiency of Hypersonic Scramjet

2014 ◽  
Author(s):  
Mohammad A. Hossain ◽  
Md. Taibur Rahman ◽  
Mohammad Ikthair Hossain Soiket ◽  
Sarzina Hossain
Keyword(s):  
Thermal Efficiency ◽  
Fluid Velocity ◽  
Specific Impulse ◽  
Flow Analysis ◽  
Inlet Temperature ◽  
Extensive Literature ◽  
Temperature Ratio ◽  
Main Research ◽  
Overall Efficiency ◽  
Inlet Conditions

This work is focused on investigation of thermal efficiency of a Hypersonic scramjet engine and propose some improvement of thermal efficiency based on thermodynamic and fluid flow analysis. Thermal management system is one of the main research fields in scramjet design. As it has no moving parts, the total thermal efficiency depends on inlet conditions, conditions of combustor exit and conditions of the engine exit. A combustor exit condition dictates the velocity and temperature after combustion. we concentrate our focus on this section. The first part of the paper, we tried to describe the fundamental exergy relationship for scramjet and we developed the relation of exergy distribution and exergy delivery rate. From an extensive literature review, we have found the relations between fluid velocity, pressure and temperature, which is described in the later part of the paper. Our main focus is to develop a combined relation of thermal efficiency in terms of engine exit velocity, temperature and air-fuel ratio. Different characteristic parameters such as overall efficiency, thermal efficiency, specific impulse have been determined at different inlet temperature ratio or the cycle static temperature ratio (T3/T0) and an optimum inlet temperature ratio is proposed for maximum overall efficiency.

Inverted Brayton Cycle With Exhaust Gas Condensation

2017 ◽  
Author(s):  
Ian Kennedy ◽  
Zhihang Chen ◽  
Bob Ceen ◽  
Simon Jones ◽  
Colin D. Copeland
Keyword(s):  
Heat Exchanger ◽  
Water Content ◽  
Power Output ◽  
Expansion Ratio ◽  
Coolant Temperature ◽  
Inlet Temperature ◽  
Brayton Cycle ◽  
Exhaust Gas ◽  
Exhaust Gases ◽  
Turbine Expansion

Approximately 30% of the energy from an internal combustion engine is rejected as heat in the exhaust gases. An inverted Brayton cycle (IBC) is one potential means of recovering some of this energy, in order to improve the overall system efficiency. When a fuel is burnt, water and CO2 are produced and expelled as part of the exhaust gases. In an IBC, in order to reduce compression work, the exhaust gases are cooled before compression up to ambient pressure. If coolant with a low enough temperature is available, it is possible to condense some of the water out of the exhaust gases, further reducing compressor work. In this study the condensation of exhaust gas water is studied. The results show that the IBC can produce an improvement of approximately 5% in BSFC at the baseline conditions chosen and for a compressor inlet temperature of 310 K. The main factors that influence the power output are heat exchanger pressure drop, turbine expansion ratio, coolant temperature and turbine inlet temperature. A lower coolant temperature significantly increases power output, particularly when condensation occurs. Larger turbine expansion ratios produce more power and slightly lower the temperature at which condensation onset occurs. The system is very sensitive to heat exchanger pressure drop, as larger pressure drops increase the compressor pressure ratio whilst leaving the turbine expansion ratio unchanged. Higher turbine inlet pressures can also increase net power, but the higher exhaust backpressures may increase engine pumping losses. Finally, for conditions when condensation is possible, the water content of the exhaust gas has a significant influence on power output. The hydrogen to carbon ratio of the fuel has the most potential to vary the water content and hence the power generated by the system. If there is no condensation, water content has a small impact on performance. The effect on power in the condensing region is predominantly due to reduced mass flow in the compressor.

scholarly journals Design of Semi-Submersible Platform using Computational Fluid Dynamics

2020 ◽  
Vol 9 (3) ◽  
pp. 3888-3892
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Fluid Flow ◽  
Average Percentage ◽  
Eddy Simulation ◽  
Velocity Magnitude ◽  
Percentage Difference ◽  
Average Percentage Difference ◽  
The Difference ◽  
Volume Method

This paper reports based on an experimental study to simulate flow due to irregular fluid flow in a semi-submersible platform using computational fluid dynamics. In this paper we use computational fluid dynamics tools which solve simple differential equations and finite volume method (FVM). A turbulence model is considered i.e. large eddy simulation (LES). The semi-submersible model is considered as pontoons, columns, horizontal brace and deck. The pontoons are horizontal placed stadium shaped structures which are submerged into the water. The columns are structures which connect the deck and pontoons in these model circular columns are considered. The horizontal braces are circular tube-like structures which connect the two or more columns which increases the rigidity of the columns. The deck is a flat surface which provides workable area. This paper is a comparison of fluid flow at different velocity magnitude. The velocity contour, pressure contour and streamline contour are simulated and graphically represented. The numerical simulations are compared with experimental solutions and focus on vicinity of the platform. The difference in pressure, temperature and streamline flow are tabulated and graphically represented. The average percentage difference in temperature and pressure are calculated to be 73% and 128% respectively. Thus, the causation is investigated for the case and several governing parameters are recognized.

scholarly journals CFD Analysis of a Tubular Heat Exchanger for the Conditioning of Olive Paste

2021 ◽  
Vol 11 (4) ◽  
pp. 1858
Author(s):  
Claudio Perone ◽  
Roberto Romaniello ◽  
Alessandro Leone ◽  
Pasquale Catalano ◽  
Antonia Tamborrino
Keyword(s):  
Heat Exchanger ◽  
Pressure Drop ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Extraction Process ◽  
Hot Water ◽  
Inlet Temperature ◽  
Cfd Analysis ◽  
Tubular Heat Exchanger ◽  
Inlet Conditions

The use of a heat exchanger for the conditioning of the olive paste could enhance the olive oil extraction process. Particularly, paste pre-heating could reduce the malaxation time and, most of all, improve the temperature control during this process (e.g., 27 °C). In this study, a three-dimensional computational fluid dynamics (CFD) analysis of a tubular heat exchanger was carried out to better understand the influence of the inlet conditions of the olive paste on thermal and hydrodynamic behavior within it. CFD analysis was performed with SOLIDWORKS Flow Simulation (ver.2016). The heat exchanger consists of a tube-in-tube module, in which the inner tube was fed with the olive paste, while the jacket was filled of hot water. The main aim was that to predict the heat transfer and pressure drop in paste side of the exchanger. Multiple analyses by varying the mass flow rate and inlet temperature of the paste were carried out, and temperature and pressure drop were estimated. The numerical model has proved very useful in identifying the main factors affecting the optimization of the heat exchanger in order to improve the extraction process of the olive paste.

Sign in / Sign up

Export Citation Format

Share Document