Numerical Heat Transfer and Fluid Flow Modeling of a Nano-Robot Inside the Blood Stream of an Aorta

2007 ◽  
Author(s):  
M. Ghassemi ◽  
M. Varmarzyar ◽  
M. K. Ebrahimi ◽  
M. Zare
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamic ◽  
Nonlinear Partial Differential Equations ◽  
Blood Stream ◽  
Nano Technology ◽  
Medical Treatments ◽  
Numerical Heat Transfer ◽  
Promising Area ◽  
Energy Equations ◽  
Fluid Flow Modeling

The idea of nano-technology started in 1959. It has been used in different applications since its creation. One of its new areas of applications is in medicine. From medical instruments (i.e. sensors etc) to medical treatments nano-technology is playing a major role. Application of nano-robot inside human blood for health purposes is a promising area. The purpose of this study is to investigate the flow field and heat transfer modeling of a nano-robot inside the biggest human vein, Aorta. In our formulation of governing nonlinear partial differential equations, momentum and energy equations are applied to the blood and the nano-robot. The equations are solved by a computational fluid dynamic code. The velocity profile, pressure and temperature distribution of the nano-robot in direction of the blood stream as well as in opposite direction of the blood stream are calculated. Results are verified with a known experimental condition. Results show that the nano-robot does not disturb the blood stream significantly. Therefore it is safe to use such devices inside blood stream for medical purposes.

Theoretical Analysis of Resonance Tube End Wall Heating: Solution of Unsteady Fluid Dynamic and Energy Equations

2015 ◽  
Author(s):  
Ramlala P. Sinha
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamic ◽  
Stable Solution ◽  
Heat Conducting ◽  
Cross Sectional ◽  
Arbitrary Boundary ◽  
Resonance Tube ◽  
Unsteady Fluid ◽  
Energy Equations ◽  
End Wall

A solution of the highly complex unsteady compressible flow field inside a cylindrical resonance tube has been obtained numerically, assuming one dimensional, viscous, and heat conducting flow, by solving the appropriate fluid dynamic and energy equations. The resonance tube is approximated by a right circular cylinder closed at one end with a piston oscillating at resonant frequency at the other end. An iterative implicit finite difference scheme is employed to obtain the solution. The scheme permits arbitrary boundary conditions at the piston and the end wall and allows assumptions for transport properties. For the example considered herein, the solution predicts a rise of 95°F in the mean end wall temperature, from 60°F to 155°F, in 14.313 milliseconds which is in good agreement with the experimentally observed values. The solution would also be valid for tapered tubes if the variations in the cross-sectional area are small. In successfully predicting the resonance tube results, an innovative simple but stable solution of unsteady fluid dynamic and energy equations is provided here for wide ranging research, development, and industrial applications in solving a variety of complex fluid flow heat transfer problems. The method is directly applicable to pulsed or pulsating flow and wave motion thermal energy transport, fluid-structure interaction heat transfer enhancement, and fluidic pyrotechnic initiation devices.

Solution of Unsteady Fluid Dynamic and Energy Equations for High-Speed Oscillating Compressible Flows and Blast Wave Propagations

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Ramlala P. Sinha
Keyword(s):  
Heat Transfer ◽  
Blast Wave ◽  
High Speed ◽  
Fluid Dynamic ◽  
Stable Solution ◽  
Heat Conducting ◽  
Arbitrary Boundary ◽  
One Dimensional ◽  
Unsteady Fluid ◽  
Energy Equations

Abstract A solution of the highly complex unsteady high-speed oscillating compressible flow field inside a cylindrical tube has been obtained numerically, assuming one-dimensional, viscous, and heat conducting flow, by solving the appropriate fluid dynamic and energy equations. The tube is approximated by a right circular cylinder closed at one end with a piston oscillating at very high resonant frequency at the other end. An iterative implicit finite difference scheme is employed to obtain the solution. The scheme permits arbitrary boundary conditions at the piston and the end wall and allows assumptions for transport properties. The solution would also be valid for tapered tubes if the variations in the cross-sectional area are small. In successfully predicting the time-dependent results, an innovative simple but stable solution of unsteady fluid dynamic and energy equations is provided here for wide-ranging research, design, development, analysis, and industrial applications in solving a variety of complex fluid flow heat transfer problems. The method is directly applicable to pulsed or pulsating flow and wave motion thermal energy transport, fluid–structure interaction heat transfer enhancement, and fluidic pyrotechnic initiation devices. It can further be easily extended to cover muzzle blasts and nuclear explosion blast wave propagations in one-dimensional and/or radial spherical coordinates with or without including energy generation/addition terms.

Analyze the Effect of Thermal Conductivity of Cold Insulation Materials in Cryogenic Engineering

2014 ◽  
Vol 986-987 ◽  
pp. 17-20
Author(s):  
Ming Leng ◽  
Zhao Ci Li ◽  
Jian Yuan Feng ◽  
Guang Rang Li ◽  
Zhao Chen Liu
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Low Temperature ◽  
Foam Glass ◽  
Nonlinear Partial Differential Equations ◽  
Heat Transfer Process ◽  
Insulation Layer ◽  
Insulation Materials ◽  
Energy Equations ◽  
Thermal Conductivities

The pipe heat transfer models were constructed, respectively, to simulate the cryogenic insulated structure, nonlinear partial differential equations was obtained considering the temperature-dependent variation in thermal conductivity of insulation materials. In order to get the temperature profile of insulation layer, Kirchhoff integral method was introduced to process, program, and iteratively calculate the simplified energy equations. The influence of heat-transfer process related to the thermal conductivities of four cold insulators was analyzed. Results indicate that phenolic foam, hydrophobic perlite, and RPUR have superior low-temperature insulation at cryogenic environment, while foam glass has better low-temperature insulation at normal temperature. The thickness of inner cryogenic-insulation layer can be reduced largely by using a multicomponent cold insulator in the discharge pipe of LNG stations, which can save both materials and costs. Meanwhile, it offers a new method to solve variable thermal conductivities.

Time-Dependent Solution of Unsteady Fluid Flow Equations for High Speed Oscillating Compressible Flows and Blast Wave Propagations

2020 ◽  
Author(s):  
Ramlala P. Sinha
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Blast Wave ◽  
High Speed ◽  
Fluid Dynamic ◽  
Time Dependent ◽  
Arbitrary Boundary ◽  
One Dimensional ◽  
Unsteady Fluid ◽  
Energy Equations

Abstract A solution of the highly complex unsteady high speed oscillating compressible flow field inside a cylindrical tube has been obtained numerically, assuming one dimensional, viscous, and heat conducting flow, by solving the appropriate fluid dynamic and energy equations. The tube is approximated by a right circular cylinder closed at one end with a piston oscillating at very high resonant frequency at the other end. An iterative implicit finite difference scheme is employed to obtain the solution. The scheme permits arbitrary boundary conditions at the piston and the end wall and allows assumptions for transport properties. The solution would also be valid for tapered tubes if the variations in the cross-sectional area are small. In successfully predicting the time dependent results, an innovative simple but stable solution of unsteady fluid dynamic and energy equations is provided here for wide ranging research, design, development, analysis, and industrial applications in solving a variety of complex fluid flow heat transfer problems. The method is directly applicable to pulsed or pulsating flow and wave motion thermal energy transport, fluid-structure interaction heat transfer enhancement, and fluidic pyrotechnic initiation devices. It can further be easily extended to cover muzzle blasts and nuclear explosion blast wave propagations in one dimensional and/or radial spherical coordinates with or without including energy generation / addition terms.

scholarly journals Experimental performance comparison between circular and elliptical tubes in evaporative condensers

2021 ◽  
Author(s):  
Giuseppe Starace ◽  
Lorenzo Falcicchia ◽  
Pierpaolo Panico ◽  
Maria Fiorentino ◽  
Gianpiero Colangelo
Keyword(s):  
Heat Transfer ◽  
Experimental Approach ◽  
Fluid Dynamic ◽  
Major Axis ◽  
Performance Comparison ◽  
Operating Conditions ◽  
Condensation Temperature ◽  
Air Cooled Condensers ◽  
Reduced Scale ◽  
Dynamic Phenomena

AbstractIn refrigeration systems, evaporative condensers have two main advantages compared to other condensation heat exchangers: They operate at lower condensation temperature than traditional air-cooled condensers and require a lower quantity of water and pumping power compared to evaporative towers. The heat and mass transfer that occur on tube batteries are difficult to study. The aim of this work is to apply an experimental approach to investigate the performance of an evaporative condenser on a reduced scale by means of a test bench, consisting of a transparent duct with a rectangular test section in which electric heaters, inside elliptical pipes (major axis 32 mm, minor axis 23 mm), simulate the presence of the refrigerant during condensation. By keeping the water conditions fixed and constant, the operating conditions of the air and the inclination of the heat transfer geometry were varied, and this allowed to carry out a sensitivity analysis, depending on some of the main parameters that influence the thermo-fluid dynamic phenomena, as well as a performance comparison. The results showed that the heat transfer increases with the tube surface exposed directly to the air as a result of the increase in their inclination, that has been varied in the range 0–20°. For the investigated conditions, the average increase, resulting by the inclination, is 28%.

scholarly journals Heat Transfer and Flow on the Blade Tip of a Gas Turbine Equipped With a Mean-Camberline Strip

2001 ◽  
Vol 123 (4) ◽  
pp. 704-708 ◽  
Author(s):  
A. A. Ameri
Keyword(s):  
Heat Transfer ◽  
Sharp Edge ◽  
Tip Leakage Flow ◽  
Transfer Coefficients ◽  
Large Power ◽  
Tip Leakage ◽  
Numerical Heat Transfer ◽  
Heat Transfer Coefficients ◽  
Blade Tip ◽  
Convective Heat Transfer Coefficients

Experimental and computational studies have been performed to investigate the detailed distribution of convective heat transfer coefficients on the first-stage blade tip surface for a geometry typical of large power generation turbines (>100 MW). In a previous work the numerical heat transfer results for a sharp edge blade tip and a radiused blade tip were presented. More recently several other tip treatments have been considered for which the tip heat transfer has been measured and documented. This paper is concerned with the numerical prediction of the tip surface heat transfer for radiused blade tip equipped with mean-camberline strip (or “squealer” as it is often called). The heat transfer results are compared with the experimental results and discussed. The effectiveness of the mean-camberline strip in reducing the tip leakage and the tip heat transfer as compared to a radiused edge tip and sharp edge tip was studied. The calculations show that the sharp edge tip works best (among the cases considered) in reducing the tip leakage flow and the tip heat transfer.

Turbulent Transport in Pin Fin Arrays: Experimental Data and Predictions

2005 ◽  
Author(s):  
F. E. Ames ◽  
L. A. Dvorak
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Boundary Layers ◽  
Fluid Dynamic ◽  
Turbulent Transport ◽  
Turbulence Models ◽  
Reynolds Numbers ◽  
Velocity Profiles ◽  
Pin Fin ◽  
Pin Fin Arrays

The objective of this research has been to experimentally investigate the fluid dynamics of pin fin arrays in order to clarify the physics of heat transfer enhancement and uncover problems in conventional turbulence models. The fluid dynamics of a staggered pin fin array have been studied using hot wire anemometry with both single and x-wire probes at array Reynolds numbers of 3000; 10,000; and 30,000. Velocity distributions off the endwall and pin surface have been acquired and analyzed to investigate turbulent transport in pin fin arrays. Well resolved 3-D calculations have been performed using a commercial code with conventional two-equation turbulence models. Predictive comparisons have been made with fluid dynamic data. In early rows where turbulence is low, the strength of shedding increases dramatically with increasing in Reynolds numbers. The laminar velocity profiles off the surface of pins show evidence of unsteady separation in early rows. In row three and beyond laminar boundary layers off pins are quite similar. Velocity profiles off endwalls are strongly affected by the proximity of pins and turbulent transport. At the low Reynolds numbers, the turbulent transport and acceleration keep boundary layers thin. Endwall boundary layers at higher Reynolds numbers exhibit very high levels of skin friction enhancement. Well resolved 3-D steady calculations were made with several two-equation turbulence models and compared with experimental fluid mechanic and heat transfer data. The quality of the predictive comparison was substantially affected by the turbulence model and near wall methodology.

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