With the development of simulation programs, it is necessary to simulate the problems that occur in the human body that are related to mechanical engineering. Whereas blood is a liquid with mechanical properties, the artery is a substance that also contains mechanical properties. Smoking increases blood viscosity, and this viscosity affects the velocity and blood pressure as well as the artery itself. In this research article, the effect of blood viscosity on the aorta will be studied because it is one of the main arteries of the heart and obtains blood flow in the artery. The blood’s kinetic equations were solved using the COMSOL program’s laminar processor, and fluid–structure interaction was utilized to connect the mechanics of motion with the stresses that affect the artery. In addition, the effect of viscosity on the deformation of the artery and its movement was studied, and the result showed that most of the blood does not reach the branches of the artery, where the speed of blood flow was 0.18 m/s at the value of the viscosity of 0.1 Pa s. The increase in viscoelasticity leads to an increase in pressure at the beginning of the carotid artery, which hinders the flow of blood. The velocity of blood flow decreases with the increase in viscosity, and this reduces pressure on the artery walls, as the stress on 0.1 Pa s was equal to 16,705 Pa s (m.124). An artery’s deformation is directly related to the stresses on it, and when the deformation goes down, the artery’s size goes down.

No abstract

Enhancing heat transfer efficiency is crucial for the performance of heat exchangers, and the implementation of corrugated tubes has been shown to be an effective approach. In this study, a numerical investigation was conducted to analyze the impact of varying corrugation depths in rod baffles and two types of corrugated tubes (1 start and 3 start) on heat transfer and pressure drop characteristics. Water was used as the working fluid on the shell side of the heat exchanger, while a constant wall temperature was maintained on the tube side. Corrugation ratios (e/dh) of 0.1 and 0.13, pitch (p) of 10, 20, and 30 mm, and two types of rod baffle spacing (x/d) of 1.25 and 1.375 were considered. The analysis was performed in the turbulent flow regime with Reynolds numbers ranging from 4,000 to 24,000. Three-dimensional governing equations were solved using the standard k-ε model in ANSYS-Fluent 18.1 to examine the flow behavior within the corrugated tubes. The results indicated that a primary vortex was formed in the main flow due to the induced rotational flow along the helical path, as well as a secondary vortex behind the rib. These vortices disrupted the boundary layer and promoted flow mixing between layers. The average Nusselt number for corrugated tubes (pitch 10 mm) increased by 25% and 55% for corrugation depths of 0.1 and 0.13, respectively. However, the friction factor for corrugated tubes with (e/dh) = 0.1 and 0.13 was found to be higher than that of smooth tubes by 66%, 133%, and 130%. With the incorporation of both corrugated tubes and rod baffles, the thermal enhancement factor reached 1.9 for x/d = 1.25 and 1.97 for x/d = 1.375 at the same pumping power (50 mm). This study provides valuable insights into the effects of corrugated tubes and rod baffles on heat exchanger performance for various Reynolds numbers.

No abstract