Peristalsis subject to Entropy Generation

Abstract

Peristalsis is an important activity that is involved extensively in real life situations. Physiological situations greatly witnessed the existence of this phenomenon. Chyme movement in stomach, bile movement, spermatic transportation, ovum movement, urine transport in bladder etc. are few activities found in this regard. This inherent property is responsible for transportation of materials from one part to others. Due to its novel involvement in physiology it is found convenient to build the clinical devices based on this principle. This is found advantageous in the way of diagnosis and cure of certain diseases. This results in vast majorities of new innovations in the fields of biomedical sciences. Many medical devices like heart lung machine (used in open heart surgery supplies the oxygenated blood to aorta that deliver it to rest body part), dialysis machine (through which blood is filter and toxin and solutes are removed from blood), endoscope (used as diagnosis purposes) etc. work under peristalsis. Many pumping devices like roller pumps, finger and hose pumps etc. are also mentioned in this direction. Human physiology systems are found very complex, spontaneous and irreversible. During these complex processes, energy conversion has always been witnessed, which also results in loss of energy in many physiological situations. All these processes cause change in thermodynamics of the system. This may also leads to disorderliness of the system. For stable system it is very essential to study the system and found the factors for these disorderliness and obtain the ways to optimize these. This system’s disorderliness is referred as entropy. Mathematical modeling is found very beneficial to study these analyses and to get an estimate about the factor to increase entropy. Some measures are determined to control these. Mathematical modeling also results in reduction of the experimental expenses and time. In this way firstly data is analyzed theoretically through mathematical model then on the basis of estimate the experiments and further testing techniques are adopted. Here second law of thermodynamics is adopted for entropy analysis. During fluid flow analysis the fluid friction, chemical reactions, thermal irreversibility via magnetic field or radiation, diffusion irreversibility etc. are some factors that may lead to change in entropy. Hence in this thesis different factor are checked for entropy generation in field of peristalsis. Different types of materials with nanofluid features are examined. Effect of different embedded parameters on entropy are observed and analyzed physically. This thesis is structured as follow: Chapter one includes the basic knowledge and literature about the concepts used in this direction. This contains the detailed analysis of peristalsis, non- Newtonian fluids, nanofluids, magnetohydrodynamics (MHD) and current, chemical reaction, porous medium, slip conditions, compliant walls, mixed convection, heat and mass transfer and entropy. This chapter also covers the basic laws for the analysis including mass, momentum, energy and concentration conservation laws. Chapter two contains the mixed convective flow due to peristalsis. Silver water nanofluid has been evaluated in this study. Hall effect and radiation are also studied. Slip conditions are employed at the channel walls. Comparison is set for different shapes of nanomaterial including bricks, cylinders and platelets. Entropy analysis is attempted for different shaped nanoparticles. Technique of perturbation is adopted for solution of system. Effect of sundry parameters on Bejan number and trapping is also accounted. Contents of this chapter are published in Journal of Molecular Liquids, 248 (2017) 447-458. Chapter three covers the magneto-nanoparticles in water based nanoliquids. Mixed convection and viscous dissipation are also considered. Second order slip conditions are accounted at the boundary. Entropy generation and Bejan number are evaluated. Streamlines are also part of the study. Analysis is based on the comparison between Maxwell and Hamilton Crosser models. The content of this chapter is accepted and in press in Scientia Iranica, 27 (2020) 3434-3446. Chapter four aims to cover the concept of hybrid nanofluid. Study is analyzed for titanium oxides and copper nanoparticles with water as base fluid. Secondary velocity is also studied in view of rotating frame. Hall effect and porous medium are present. Convective boundary conditions are accounted. Non-uniform hear source/ sink and radiation are also present. Maxwell-Garnetts model also help to investigate the thermal conductivity for hybrid nanofluid. Entropy generation is also examined. NdSolve of Mathematica is adopted as solution methology. The contents of this chapter are published in Journal of Thermal Analysis and Calorimetry, 143 (2021) 1231-1249. Chapter five reports the investigation on entropy in a channel with inclined magnetic field. Williamson nanofluid is utilized here. Buongiorno model with Brownian motion and thermophoresis effects is utilized. Compliant wall of channel are considered. Further slip effects at boundary are investigated. Entropy anlaysis contains the thermal, Joule, fluid friction and diffusion irreversibilities. Contents of this chapter are reported in Physica Scripta, 94 (2019) 10.1088/1402- 4896/ab34b7. Chapter six addresses the peristaltic phenomenon in curved configuration. Williamson fluid with well-known Soret and Dufour effects are incorporated. MHD characteristics are examined by applying it in radial direction. Curvilinear coordinates are chosen to model the problem. Flexible wall characteristics are incorporated in terms of elastance, rigidity and stiffness. Partial slip is accounted. Considered flow analysis is solved via perturbation. Wessienberg number is adopted to prepare the zeroth and first order approximations. Steamlines are also plotted to investigate the bolus size. Results of this chapter are published in Computer Methods and Programs in Biomedicine, 180 (2019) 105013. Chapter seven communicates the peristalsis for Sisko nanofluid. This chapter further highlights the effects of nonlinear thermal radiation and Joule heating. Slip conditions are also employed. Entropy generation is investigated for viscous dissipation, nonlinear thermal radiation and diffusion and Joule heating irreversibilities. NDSolve is employed as solution technique which gave the convergent results in less computation time. Results are also validated by comparison. This chapter is published in Journal of Thermal Analysis and Calorimetry, 139 (2020) 2129–2143. Chapter eight investigates the study of endoscope impact on peristalsis in present of porous medium. Sisko fluid is utilized for shear thinning effects. Modified Darcy law is incorporated for reporting the porous medium effects. Entropy is accounted for different pertinent parameters. Convective conditions are accounted here. The findings of this analysis are reported in Physica A, 536 (2019) 120846. Chapter nine provide attention on entropy generation for Rabinowitsch nanofluid. A comparative study based on viscous, shear thickening and shear thinning fluid is reported. Chemical reaction is studied. A non-uniform heat source/sink parameter is involved in the energy equation with viscous dissipation and Brownian motion and thermophoresis effects. Slip is also considered on the boundary. Velocity, temperature, concentration, entropy and heat transfer coefficient are examined for comparison. The results of this research is published in Applied nanoscience, 10 (2020) 4177–4190. Chapter ten covers the entropy analysis for homogeneous-heterogeneous reaction. Prandtl nanofluid is utilized in peristalsis. Magnetic field is applied in the perpendicular direction to flow. Joule heating is also considered. Buongiorno model is utilized. Second law of thermodynamics is employed to study entropy generation. Graphs are plotted for velocity, temperature, homogeneous-heterogeneous reaction and heat transfer coefficient and entropy. The findings of this chapter are reported in European Journal Physical Plus, 135 (2020) 296. Chapter eleven investigates the entropy in view of variable thermal conductivity. Third grade fluid for peristalsis is adopted. MHD and Joule heating are considered. Compliant characteristics of channel walls are outlined. Graphs are plotted numerically via NDSolve of Mathematica. Mixed convection is involved in this study. Results are examined graphically. Trapping is also examined via streamlines. This study is published in European Journal Physical Plus, 135 (2020) 421.