Fluid Dynamic Simulation and Optimization of Compact Heat Exchangers with Louver Fins

2015 ◽  
Vol 798 ◽  
pp. 205-209
Author(s):  
Diego Amorim Caetano de Souza ◽  
Lúben Cabezas Gómez ◽  
José Antônio da Silva
Keyword(s):  
Heat Exchangers ◽  
Energy Use ◽  
Fluid Dynamic ◽  
Flow Behavior ◽  
Mechanical Energy ◽  
The Body ◽  
Compact Heat Exchangers ◽  
Simulation And Optimization ◽  
Wide Range ◽  
Computational Fluid Dynamics Cfd

Every technological process developed since the beginning of humanity to the present day always involves some kind of energy use, either mechanical energy of the body or energy from burning fuel or the solar energy obtained from the sun. To manipulate and use that energy, the man always developed resources and equipment to allow it. Among the wide range of equipment, heat exchangers, designed to transfer heat from one fluid to another, will be analyzed in this work. To do this analysis, are used computational fluid dynamics (CFD) techniques to analyze the flow behavior of a compact heat exchanger, of tube and louvered fins type. After this step that aims to pull the parameters of efficiency, optimization features will be used to be able to propose a model for more efficient fin.

scholarly journals Aerodynamic Investigation of Datum and Slotted Blade Profiles under Different Mach Number Conditions

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1673
Author(s):  
Yumeng Tang ◽  
Yangwei Liu
Keyword(s):  
Mach Number ◽  
Fluid Dynamic ◽  
Mechanical Energy ◽  
Adverse Pressure Gradient ◽  
Dissipation Function ◽  
Suction Surface ◽  
Trailing Edge ◽  
Loss Mechanism ◽  
Wide Range ◽  
Downstream Flow

Mach number effects on loss and loading are evaluated in both the datum and slotted compressor profiles under a wide range of incidences based on two-dimensional (2D) computational fluid dynamic (CFD) simulations. First, total pressure loss and loading abilities are compared. Then, three kinds of deficit thickness are defined and evaluated, and a correlation is made between the loading and the momentum deficit thickness at the profile trailing edge. Finally, the nondimensionalized destruction of mean mechanical energy and dissipation function are employed to analyze the loss mechanism. The slotted profile broadens the low loss range towards the positive incidence range. The slotted profile allows a higher diffusion factor (DF) than the datum profile. It is hard to distinguish failure simply based on the DF values, whereas the Zweifel loading coefficient connects well with the low momentum deficit in the profile trailing edge. The peak of the V-shaped distributions in the Ψ - θ d e f plot could better suggest the design condition and determine the correct operating range despite the occurrence of bulk separation. The slotted profile gains the ability of the boundary layer flow near the suction surface to resist the adverse pressure gradient, hence, a reduced shear thickness and a uniformed downstream flow field is obtained.

Effects of Intracoronary Fentanyl on Left Ventricular Mechanoenergetics in the Excised Cross-circulated Canine Heart (Revised Publication)

1997 ◽  
Vol 87 (3) ◽  
pp. 658-666 ◽  
Author(s):  
Kunihisa Kohno ◽  
Miyako Takaki ◽  
Kazunari Ishioka ◽  
Yasunori Nakayama ◽  
Shunsuke Suzuki ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Energy Use ◽  
Mechanical Energy ◽  
Systolic Pressure ◽  
Left Ventricular ◽  
Canine Heart ◽  
Loading Conditions ◽  
Wide Range ◽  
Total Mechanical Energy ◽  
Lv Volumes

Background It is still unclear whether fentanyl directly alters left ventricular (LV) contractility and oxygen consumption. This is because of the difficulty in defining and evaluating contractility and energy use independently of ventricular loading conditions and heart rate in beating whole hearts. Methods This study was conducted to clarify the mechanoenergetic effects of intracoronary fentanyl in six excised cross-circulated canine hearts. The authors used the framework of the Emax (a contractility index)-PVA (systolic pressure-volume area, a measure of total mechanical energy)-VO2 (myocardial oxygen consumption per beat) relationship practically independent of ventricular loading conditions. The authors measured LV pressure, volume, coronary flow, and arteriovenous oxygen content difference to calculate Emax, PVA, and VO2. They first obtained the VO2-PVA relationship for varied LV volumes at control Emax. The authors then obtained the VO2-PVA relationship at a constant LV volume, whereas coronary blood fentanyl concentration was increased in steps up to 240 ng/ml. Finally, they obtained the VO2-PVA relationship for varied LV volumes at the final dose of fentanyl. Results Fentanyl at any concentrations did not significantly change Emax, PVA, and VO2 from the control. The linear end-systolic pressure-volume relations and their slopes were virtually the same between the control and fentanyl volume loading in each heart. Further, either the slope (oxygen cost of PVA) or the VO2 intercept (unloaded VO2) of the linear VO2-PVA relationship remained unchanged by fentanyl. Conclusions These results indicate that intracoronary fentanyl produces virtually no effects on LV mechanoenergetics for a wide range of its blood concentration.

scholarly journals Body Shape Selection of "Bono Kampar" For Urban Concept Student Car Formula to Fulfill Indonesian Energy-Saving Standards (“KMHE”) with Aerodynamic Analysis

CFD letters ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 104-114
Author(s):  
Nazaruddin ◽  
Syafri ◽  
Yudi Saputra
Keyword(s):  
Drag Coefficient ◽  
Computational Fluid Dynamic ◽  
Body Shape ◽  
Energy Use ◽  
Energy Savings ◽  
Fluid Dynamic ◽  
Flow Simulation ◽  
The Body ◽  
Car Body ◽  
Selection Of

The body shape of a vehicle and the structure need to be considered when designing a vehicle. In addition, the shape of the body tends to significantly affect the vehicle's energy use to counter aerodynamic forces due to wind loads. Therefore, this research aims to determine the body length, width, height, wheel base and ground clearance of vehicles in the selection of Bono Kampar for Urban Concept Car Formula to Fulfill Indonesia Energy-Savings Standards (“KMHE”) with Aerodynamics Analysis. The methods used to create four models of vehicle bodies are dynamic simulation on Computational Fluid Dynamic software are coefficient drag, lift and bland force. The result showed that the car body design needs to have the smallest drag coefficient. This is because when vehicles have a large drag coefficient value, it tends to greatly influence its efficiency or performance. Furthermore, this is useful for minimizing fuel usage, and in allowing the vehicle to reduce the friction force caused by air while driving. The Computational Fluid Dynamic (CFD) software is used to obtain drag coefficients, which is used in Solid works Flow Simulation. From aerodynamic simulation results on four alternative car bodies carried out in this study, the smallest Cd (Coefficient Drag) is the second car body model, which has Drag Coefficient (Cd) of 0.21 Pa.

scholarly journals A Review on Design and optimization of shell and tube heat exchanger by varying parameters

2020 ◽  
Vol 6 (6) ◽  
Author(s):  
Shiv Kumar ◽  
Dharamveer Singh
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Fluid Dynamic ◽  
Exchange Process ◽  
Cost Savings ◽  
Thermal Control ◽  
Tube Heat Exchanger ◽  
Design And Optimization ◽  
Compact Heat Exchangers ◽  
Computation Fluid Dynamic

In recent years, thermal control systems performance has improved in numerous ways due to developments in control theory and information technology. Efforts have been made to produce more efficient heat exchangers by employing various methods of heat transfer enhancement.  An increase in heat exchanger performance can lead to a more economical design of heat exchanger which can help to make energy, material & cost savings related to a heat exchange process. Compact heat exchangers (CHEs) technologies are expected to be one of the solutions for the new generation heat exchanger.  In this paper are presented of the compact heat exchanger, Plate-fin heat exchanger, and Printed Circuit Heat Exchanger. And computation fluid dynamic is used which offers an alternative to the quick and inexpensive solution for the design and optimization of compact heat exchangers.

Air-Side Performance Characterization of Air-to-Refrigerant Heat Exchangers Using Parallel Parameterized CFD

2013 ◽  
Author(s):  
Khaled Saleh ◽  
Weizhe Han ◽  
Vikrant Aute ◽  
Reinhard Radermacher
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Cfd Simulations ◽  
Cfd Models ◽  
F Factor ◽  
Wide Range ◽  
Different Types ◽  
Computational Fluid Dynamics Cfd ◽  
Friction Performance

The goal of the study presented in this paper is to use Computational Fluid Dynamics (CFD) to characterize the heat transfer and friction performance of fins used in air-to-refrigerant heat exchangers. Five different types of fins used in air-cooled heat exchangers (HXs) are studied using Parallel Parameterized CFD (PPCFD) approach described in this paper. The fin types considered in this paper are; Plain, Wavy, Slit, Super Slit, and Louver. 3-D CFD models are built and tested for these fin types. Based on the CFD results, air side heat transfer coefficient (HTC), Colburn j factor, Fanning f factor, and pressure drop are calculated. The results from CFD simulations are compared against experimental data from the literature for the different fin types and a good agreement is found between the two. In addition, the results from CFD simulations are used to evaluate the thermal and hydraulic performance for a wide range of heat exchanger parameters such as tube diameters, fin pitch, number of rows, and frontal air velocity. The results show the advantages of using PPCFD to efficiently develop correlations for different types of fins used in air-cooled HX, with significant reduction in engineering time. The PPCFD approach can be extended to efficiently optimize novel heat transfer surfaces.

Effects of Intracoronary Fentanyl on Left Ventricular Mechanoenergetics in the Excised Cross-circulated Canine Heart 

1997 ◽  
Vol 86 (6) ◽  
pp. 1350-1358 ◽  
Author(s):  
Kunihisa Kohno ◽  
Miyako Takaki ◽  
Kazunari Ishioka ◽  
Yasunori Nakayama ◽  
Shunsuke Suzuki ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Energy Use ◽  
Mechanical Energy ◽  
Systolic Pressure ◽  
Left Ventricular ◽  
Canine Heart ◽  
Loading Conditions ◽  
Wide Range ◽  
Total Mechanical Energy ◽  
Lv Volumes

Background It is still unclear whether fentanyl directly alters left ventricular (LV) contractility and oxygen consumption. This is because of the difficulty in defining and evaluating contractility and energy use independently of ventricular loading conditions and heart rate in beating whole hearts. Methods This study was conducted to clarify the mechanoenergetic effects of intracoronary fentanyl in six excised cross-circulated canine hearts. The authors used the framework of the E(max) (a contractility index)-PVA (systolic pressure-volume area, a measure of total mechanical energy)-VO2 (myocardial oxygen consumption per beat) relationship practically independent of ventricular loading conditions. The authors measured LV pressure, volume, coronary flow, and arteriovenous oxygen content difference to calculate E(max), PVA, and VO2. They first obtained the VO2-PVA relationship for varied LV volumes at control E(max). The authors then obtained the VO2-PVA relationship at a constant LV volume, whereas coronary blood fentanyl concentration was increased in steps up to 240 ng/ml. Finally, they obtained the VO2-PVA relationship for varied LV volumes at the final dose of fentanyl. Results Fentanyl at any concentrations did not significantly change E(max), PVA, and VO2 from the control. The linear end-systolic pressure-volume relations and their slopes were virtually the same between the control and fentanyl volume loading in each heart. Further, either the slope (oxygen cost of PVA) or the VO2 intercept (unloaded VO2) of the linear VO2-PVA relationship remained unchanged by fentanyl. Conclusions These results indicate that intracoronary fentanyl produces virtually no effects on LV mechanoenergetics for a wide range of its blood concentration.

scholarly journals Simulation of oil cooling of a submersible motor using a heat exchanger

2021 ◽  
pp. 69-75
Author(s):  
R. R. Gizatullin ◽  
◽  
S. N. Peshcherenko ◽  
N. A. Lykova ◽  
◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Flow Direction ◽  
Mechanical Energy ◽  
Thermal Contact ◽  
Heat Removal ◽  
Annular Channel ◽  
Electrical Energy ◽  
The Body ◽  
Submersible Motor

Submersible motors are part of submersible oil production pumps that convert electrical energy, which is supplied through a cable from VSD, into mechanical energy of pump rotation. Currently, in about 30% of cases, the failure of an electrical submersible pump is due to a failure of the submersible motor. One of the main causes of failures is overheating of the stator winding insulation. Overheating of submersible oil-filled electric motors occurs because more heat is generated inside the motor than is removed through its outer surface. To intensify the heat removal, it is proposed to connect a heat exchanger in series with the motor and to organize the circulation of the oil in a closed loop. Both in the submersible motor and in the heat exchanger, oil flows along the annular gap along the inner surface of the housing, the oil channel is closed through a hole inside the shaft. The aim of the work is to select such a configuration of the annular channel, in which its length would be minimal. Intensification of heat removal by increasing the speed of the coolant is not advisable, because requires the motor to be equipped with a powerful pump for pumping oil, which will become an additional source of heat. Therefore, it was decided to increase the surface area of the annular channel through which heat, through the body of the installation, is removed to the well fluid. A series of calculations was performed for heat exchangers with smooth walls, with fins (perpendicular to the flow direction), and with spiral grooves (which additionally increase the length of the trajectory of oil particles and the time of their thermal contact with the stacks of the heat exchanger body). Computational fluid dynamics calculations showed that heat exchangers made according to the first two design options removed less than half of the heat. According to the third option, the oil was cooled practically to the temperature of the well fluid with a heat exchanger length of about 10% of the submersible motor length.

scholarly journals Study of the Effect of Vertical Airfoil Endplates on Diffusers in Vehicle Aerodynamics

Designs ◽  
2021 ◽  
Vol 5 (3) ◽  
pp. 45
Author(s):  
Laura Porcar ◽  
Willem Toet ◽  
Pedro Javier Gamez-Montero
Keyword(s):  
Cfd Simulation ◽  
Fluid Dynamic ◽  
Flow Behavior ◽  
Simulation Software ◽  
The Body ◽  
Ride Height ◽  
Diffuser Flow ◽  
Vehicle Aerodynamics ◽  
High Level ◽  
Ahmed Body

Diffusers and the floor ahead of them create the majority of the downforce a vehicle creates. Outside motorsports, the diffuser is relatively unused, although its interaction with the ground is a consistent field of study owing to the aerodynamic benefits. The diffuser flow behavior is governed by three fluid-mechanical mechanisms: ground interaction, underbody upsweep, and diffuser upsweep. In addition, four different flow regimes appear when varying ride height, the vortices of which have great importance on downforce generation. The present study focuses on the diffuser’s fluid-dynamic characteristics undertaken within an academic framework with the objective of finding and understanding a high level of performance in these elements. Once the functioning of diffusers has been analyzed and understood, a new configuration is proposed: rear vertical airfoil endplates. The aim of the paper is to study the effect in performance of vertical airfoil endplates on diffusers in vehicle aerodynamics in a simplified geometry. The candidate to this geometry is the inversed Ahmed body, a geometry that is used as a model that simulates the flow behavior of car diffusers. Three different diffuser configurations are performed, namely 0° diffuser, 25° diffuser, and in the third case vertically installed rear vertical airfoil endplates are added to the 25° diffuser Ahmed body to change the flow field. These analyses are carried out by using open-source CFD simulation software OpenFOAM. An inlet velocity of 20 m/s is considered, as this is a typical velocity when cornering in motorsport. It is concluded that the 25° diffuser configuration generated more downforce than the 0° diffuser, which makes sense as the aim of adding a diffuser is to increase the amount of downforce produced. In addition, and as a result of the newly proposed configuration, the 25° diffuser Ahmed body with the vertical airfoil endplates emerges in a substantial increase of downforce thanks to the low-pressure zone generated at the back of the body.

Development of 1 MWe Supercritical CO2 Test Loop

2015 ◽  
Author(s):  
Jeff Moore ◽  
Klaus Brun ◽  
Neal Evans ◽  
Chiranjeev Kalra
Keyword(s):  
Heat Exchangers ◽  
High Efficiency ◽  
Material Selection ◽  
Flow Behavior ◽  
Brayton Cycle ◽  
Compact Heat Exchangers ◽  
Southwest Research Institute ◽  
Test Loop ◽  
Turbo Expander ◽  
Cycle Efficiency

Recent studies have demonstrated that sCO2 in a closed-loop recompression. Brayton cycle offers equivalent or higher cycle efficiency when compared with supercritical- or superheated-steam cycles at temperatures relevant for CSP applications. With funding under the SunShot initiative, the authors are developing a high-efficiency sCO2 turbo-expander for the solar power plant duty cycle profile and novel compact heat exchangers for the sCO2 Brayton cycle. However, no test loop exists to test the turbine and heat exchangers under development. Therefore, a customized test loop is being developed at Southwest Research Institute that will accommodate the full test pressures (80 to 280 bar) and temperatures (45 to 700°C) of the proposed Brayton cycle. The paper describes the design methodology to predict the pipe flow behavior and thermal growths as well as material selection. A customized natural gas fired heater is currently being designed, since no heater like it is available currently.

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