scholarly journals Effect of endoscope on the peristaltic transport of a couple stress fluid with heat transfer: Application to biomedicine

2019 ◽  
Vol 8 (1) ◽  
pp. 619-629 ◽  
Author(s):  
K. Ramesh ◽  
M. Devakar
Keyword(s):  
Heat Transfer ◽  
Couple Stress ◽  
Medical Engineering ◽  
Horizontal Tube ◽  
Vertical Tube ◽  
Long Wavelength ◽  
Flow Parameters ◽  
Wide Range ◽  
Cylindrical Coordinate ◽  
Frictional Forces

Abstract In this investigation, we have studied the problem of peristaltic flow with heat transfer through the gap between coaxial inclined tubes where the inner tube is rigid and the outer tube has sinusoidal wave travelling down its wall. The problem has been formulated in cylindrical coordinate system. The equations governing the flow have been simplified under the long wavelength and low Reynolds number assumptions. The exact solution is obtained for the temperature profile. The perturbation solutions for the velocity and pressure gradient are obtained for small couple stress parameter. Pressure difference per wavelength and frictional forces on the tube walls have been computed numerically. Results are demonstrated for various flow parameters. The better pumping results occur in vertical tube, while less pumping is seen in horizontal tube. The size of trapped bolus is small in triangular wave as compared to other waves. The present study has a wide range of applications in bio-medical engineering like the transport phenomenon in peristaltic micro pumps.

Thermal Properties of Couple-Stress Fluid Flow in an Asymmetric Channel With Peristalsis

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Y. Abd elmaboud ◽  
Kh. S. Mekheimer ◽  
A. I. Abdellateef
Keyword(s):  
Heat Transfer ◽  
Couple Stress ◽  
Wave Train ◽  
Pressure Rise ◽  
Couple Stress Fluid ◽  
Two Dimensional ◽  
Asymmetric Channel ◽  
Long Wavelength ◽  
Axial Pressure Gradient ◽  
Frictional Forces

The heat transfer characteristics of a couple-stress fluid (CSF) in a two-dimensional asymmetric channel is analyzed. The channel asymmetry is produced by choosing the peristaltic wave train on the walls to have different amplitudes and phase. Mathematical modeling corresponding to the two-dimensional couple stress fluid is made. Analytical expressions for the axial velocity, stream function, heat transfer, and the axial pressure gradient are established using long wavelength assumption. Numerical computations have been carried out for the pressure rise per wavelength. The influence of various parameters of interest is seen through graphs on frictional forces, pumping and trapping phenomena, and temperature profile.

An Analytical Study of Laminar Film Condensation: Part 2—Single and Multiple Horizontal Tubes

1961 ◽  
Vol 83 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Michael Ming Chen
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Horizontal Tube ◽  
Vertical Tube ◽  
Film Condensation ◽  
Transfer Coefficients ◽  
Inertia Effects ◽  
Horizontal Tubes ◽  
Laminar Film ◽  
Laminar Film Condensation

The boundary-layer equations for laminar film condensation are solved for (a) a single horizontal tube, and (b) a vertical bank of horizontal tubes. For the single-tube case, the inertia effects are included and the vapor is assumed to be stationary outside the vapor boundary layer. Velocity and temperature profiles are obtained for the case μvρv/μρ ≪ 1 and similarity is found to exist exactly near the top stagnation point, and approximately for the most part of the tube. Heat-transfer results computed with these similar profiles are presented and discussed. For the multiple-tube case, the analysis includes the effect of condensation between tubes, which is shown to be partly responsible for the high observed heat-transfer rate for vertical tube banks. The inertia effects are neglected due to the insufficiency of boundary-layer theory in this case. Heat-transfer coefficients are presented and compared with experiments. The theoretical results for both cases are also presented in approximate formulas for ease of application.

Peristaltic Flow of a Jeffery Fluid with Heat Transfer in an Inclined Porous Tube under the Influence of Slip and Variable Viscosity

2019 ◽  
Vol 393 ◽  
pp. 16-30 ◽  
Author(s):  
Gudekote Manjunatha ◽  
Hanumesh Vaidya ◽  
Choudhari Rajashekhar ◽  
K.V. Prasad
Keyword(s):  
Heat Transfer ◽  
Frictional Force ◽  
Variable Viscosity ◽  
Pressure Rise ◽  
Velocity Slip ◽  
Slip Parameter ◽  
Porous Tube ◽  
Closed Form Solutions ◽  
Long Wavelength ◽  
Frictional Forces

The present paper investigates the role of heat transfer on peristaltic transport of Jeffery liquid in a porous tube. The effect of variable viscosity and slip impacts are taken into account. The closed-form solutions are obtained with the help of long wavelength and small Reynolds number. The results of physiological parameters on velocity, pressure rise, frictional force, trapped bolus, and temperature are plotted graphically. It is seen that the pressure rise and the frictional forces decline with an expansion in the viscosity parameter. The study further demonstrates that an increase in the value of the slip parameter significantly alters the pressure rise, frictional force, and temperature. Moreover, the volume of trapped bolus increases with an increase in the value of the velocity slip parameter.

Effect of Circumferentially Nonuniform Heating on Laminar Combined Convection in a Horizontal Tube

1978 ◽  
Vol 100 (1) ◽  
pp. 63-70 ◽  
Author(s):  
S. V. Patankar ◽  
S. Ramadhyani ◽  
E. M. Sparrow
Keyword(s):  
Heat Transfer ◽  
Secondary Flow ◽  
Forced Convection ◽  
Horizontal Tube ◽  
Nonuniform Heating ◽  
Convection Flow ◽  
Nusselt Numbers ◽  
Wide Range ◽  
Bottom Heating ◽  
Over The Top

An analytical study has been made of how the circumferential distribution of the wall heat flux affects the forced/natural convection flow and heat transfer in a horizontal tube. Two heating conditions were investigated, one in which the tube was uniformly heated over the top half and insulated over the bottom, and the other in which the heated and insulated portions were reversed. The results were obtained numerically for a wide range of the governing buoyancy parameter and for Prandtl numbers of 0.7 and 5. It was found that bottom heating gives rise to a vigorous buoyancy-induced secondary flow, with the result that the average Nusselt numbers are much higher than those for pure forced convection, while the local Nusselt numbers are nearly circumferentially uniform. A less vigorous secondary flow is induced in the case of top heating because of temperature stratification, with average Nusselt numbers that are substantially lower than those for bottom heating and with large circumferential variations of the local Nusselt number. The friction factor is also increased by the secondary flow, but much less than the average heat transfer coefficient. It was also demonstrated that the buoyancy effects are governed solely by a modified Grashof number, without regard for the Reynolds number of the forced convection flow.

Flow and Heat Transfer in Heat Recovery Steam Generators

2007 ◽  
Vol 129 (3) ◽  
pp. 232-242 ◽  
Author(s):  
N. Hegde ◽  
I. Han ◽  
T. W. Lee ◽  
R. P. Roy
Keyword(s):  
Heat Transfer ◽  
Heat Recovery ◽  
Gas Flow ◽  
Horizontal Tube ◽  
Vertical Tube ◽  
Computational Method ◽  
Laboratory Model ◽  
Steam Generators ◽  
Combustion Gas ◽  
Flow And Heat Transfer

Computational simulations of flow and heat transfer in heat recovery steam generators (HRSGs) of vertical- and horizontal-tube designs are reported. The main objective of the work was to obtain simple modifications of their internal configuration that render the flow of combustion gas more spatially uniform. The computational method was validated by comparing some of the simulation results for a scaled-down laboratory model with experimental measurements in the same. Simulations were then carried out for two plant HRSGs—without and with the proposed modifications. The results show significantly more uniform combustion gas flow in the modified configurations. Heat transfer calculations were performed for one superheater section of the vertical-tube HRSG to determine the effect of the configuration modification on heat transfer from the combustion gas to the steam flowing in the superheater tubes.

MAGNETOHYDRODYNAMIC PERISTALTIC FLOW OF A COUPLE STRESS FLUID THROUGH COAXIAL CHANNELS CONTAINING A POROUS MEDIUM

2012 ◽  
Vol 12 (05) ◽  
pp. 1250088 ◽  
Author(s):  
DHARMENDRA TRIPATHI ◽  
O. ANWAR BÉG
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Couple Stress ◽  
Mechanical Efficiency ◽  
Peristaltic Flow ◽  
Width Ratio ◽  
Long Wavelength ◽  
Channel Ratio ◽  
Frictional Forces ◽  
Inner Channel

This article studies the hydromagnetic peristaltic flow of couple stress fluids through the gap between two concentric channels containing a Darcian porous medium, with the inner channel being rigid. A sinusoidal wave propagates along the outer channel. Long wavelength and low Reynolds number assumptions are used. The effects of couple stress parameter, magnetic field, permeability, and the channel ratio width on pressure and frictional forces on the inner and outer channels are depicted graphically. Mechanical efficiency and trapping are also studied. Pressure diminishes with increasing coupling and permeability parameters whereas it increases with Hartmann number and channel width ratio. Applications of the model include transport of complex bio-waste fluids and magnetic field control of gastro-intestinal disorders.

Turbulent Flow in Closely-Pitched Internally Enhanced Tubes

2000 ◽  
Author(s):  
T. S. Ravigururajan ◽  
J. Srinivasan
Keyword(s):  
Heat Transfer ◽  
Turbulent Flow ◽  
Friction Factor ◽  
Helix Angle ◽  
Independent Study ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Flow Parameters ◽  
Wide Range ◽  
Enhanced Tubes

Abstract General correlations are developed and verified for friction factor and heat transfer coefficients for single-phase turbulent flow in internally augmented tubes, with low pitch to height ratios. Data from existing investigations were collected for a wide range of tube parameters with e/d: 0.01 to 0.2; p/e: < 8; α/90: 0.2 to 1.0, and flow parameters; Re: 2000 to 250,000 and Pr: 0.66 to 37.6. The data were applied to a linear model to get normalized correlations that were then modified to approach smooth tube correlations, as the roughness variables became very small. The correlations predicted 92% of data from an independent study on microfin tubes within ± 30%. For closely-pitched enhanced tubes, the proposed correlations predict heat transfer/friction factor with better overall accuracy and are suitable for different types of internal enhancements. The heat transfer increases with decreasing p/e ratio and increasing helix angle. The effects of roughness height and pitch on both friction and heat transfer are similar to that experienced in traditional enhancement design (p/e > 8).

Flow Boiling of R134a and R134a/Propane Mixtures at Low Saturation Temperatures Inside a Plain Horizontal Tube

2008 ◽  
Vol 130 (6) ◽  
Author(s):  
A. Rabah ◽  
S. Kabelac
Keyword(s):  
Heat Transfer ◽  
Flow Boiling ◽  
Local Heat Transfer ◽  
Horizontal Tube ◽  
Local Heat ◽  
Transfer Coefficients ◽  
Azeotropic Point ◽  
Heat Transfer Coefficients ◽  
Wide Range ◽  
Maximum Decrease

Local heat transfer coefficients for flow boiling of pure 1,1,1,2-tetrafluoroethane (R134a) and binary mixtures of propane (R290) and R134a were measured. The experimental setup employed a vapor heated plain horizontal tube (di=10mm, do=12mm, L=500mm). The measurements covered a wide range of saturation temperatures (233≤Ts≤278K), mass fluxes (100≤ṁ≤300kg∕m2s), qualities (0≤ẋ≤1), and concentrations (0≤z̃≤0.65). In the zeotropic region of R134a/R290 mixtures, the measured local heat transfer coefficient was found to show a maximum decrease by a factor of 2 relative to that for pure R134a. At the azeotropic point (65% R290), it was found to increase by a factor of 1.2. The measured local heat transfer coefficients for both R134a and R134a/R290 were compared with a number of correlations.

Laminar Film Condensation on a Porous Horizontal Tube With Uniform Suction Velocity

1965 ◽  
Vol 87 (1) ◽  
pp. 95-102 ◽  
Author(s):  
N. A. Frankel ◽  
S. G. Bankoff
Keyword(s):  
Heat Transfer ◽  
Perturbation Technique ◽  
Porous Plate ◽  
Horizontal Tube ◽  
Film Condensation ◽  
Suction Velocity ◽  
Uniform Suction ◽  
Laminar Film Condensation ◽  
Wide Range ◽  
Perturbation Parameters

The analysis of Bankoff and Jain [10] of film condensation on a vertical porous plate with uniform suction velocity is extended to the case of a horizontal porous tube. Integral momentum and energy balances are written for the system, including the effects of interface drag and condensate heat capacity, and the dimensionless equations are solved using a perturbation technique. All dependent variables are expressed in a double power series in the two perturbation parameters, ξ = kΔt/μλ (acceleration parameter) and α (dimensionless suction velocity), and the resulting equations are solved up to the second order perturbation. An asymptotic solution valid for high values of α is derived, and this solution together with the perturbation solution describes the system for a wide range of α. The case of heat transfer in a zero gravity field is treated, and the Nusselt number is found to be directly proportional to the suction velocity. Based on the results it is concluded that significant increases in heat transfer are possible with the use of suction.

scholarly journals Effects of Heat and Mass Transfer on the Peristaltic Transport of MHD Couple Stress Fluid through Porous Medium in a Vertical Asymmetric Channel

2015 ◽  
Vol 2015 ◽  
pp. 1-19 ◽  
Author(s):  
K. Ramesh ◽  
M. Devakar
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Couple Stress ◽  
Couple Stress Fluid ◽  
Asymmetric Channel ◽  
Governing Equations ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Frictional Forces ◽  
Generation Parameter

The intrauterine fluid flow due to myometrial contractions is peristaltic type motion and the myometrial contractions may occur in both symmetric and asymmetric directions. The channel asymmetry is produced by choosing the peristaltic wave train on the walls to have different amplitude, and phase due to the variation of channel width, wave amplitudes and phase differences. In this paper, we study the effects of heat and mass transfer on the peristaltic transport of magnetohydrodynamic couple stress fluid through homogeneous porous medium in a vertical asymmetric channel. The flow is investigated in the wave frame of reference moving with constant velocity with the wave. The governing equations of couple stress fluid have been simplified under the long wave length approximation. The exact solutions of the resultant governing equations have been derived for the stream function, temperature, concentration, pressure gradient, and heat transfer coefficients. The pressure difference and frictional forces at both the walls are calculated using numerical integration. The influence of diverse flow parameters on the fluid velocity, pressure gradient, temperature, concentration, pressure difference, frictional forces, heat transfer coefficients, and trapping has been discussed. The graphical results are also discussed for four different wave shapes. It is noticed that increasing of couple stresses and heat generation parameter increases the size of the trapped bolus. The heat generation parameter increases the peristaltic pumping and temperature.

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