جستجوی مقالات مرتبط با کلیدواژه "fluid flow" در نشریات گروه "مکانیک"

The present study develops a numerical approach based on the mathematical models governing the behavior of fluid flow and drug transport in tumors to investigate the delivery of a macromolecule under the effect of the vascular normalization into a non-uniform tumor, including different parts of a real solid tumor. In this study, different tumor sizes in the range of  are considered. The area under the curves of the drug average distribution and its deviation in the tumor site over time is studied as the amount of drug delivered and the uniformity of delivered drug to assess the quality of drug delivery. Results show that before and after normalization, the behaviors of interstitial fluid flow and the distribution of therapeutic agent concentration depend on tumor size. Normalization in all sizes reduces the interstitial fluid pressure, which this pressure drop increases as the tumor size reduces. Normalization improves antibody concentration distribution at different times depending on tumor size. However, from the point of view of the average spatiotemporal criterion, vascular normalization improves macromolecule delivery into the tumor site in  by increasing the distribution uniformity. This research, by discussing the mechanisms affecting normalization efficiency, can provide insights for in vivo and in vitro studies that address the combination of anti-angiogenic therapy and chemotherapy.

The present work investigates the nonlinear vibration of a cantilever cylindrical micro-beam subjected to voltage and fluid flow as a micro vortex generator. As the microbeam is subjected to the fluid with given velocity, in addition to the load due to fluid added mass, the lift and drag forces as the two basic flow-induced factors affecting the dynamics of the micro-beam are modelled using the Van der pol equation. The Euler-Bernoulli beam theory is used to model the cross fluid motion of the beam under nonlinear electrostatic force as result of applied voltage. The Galerkin method is used to convert the partial differential equation to regular differential equations as well as to solve the coupled nonlinear equations governing the micro-beam motion and the wake oscillation to evaluate the response of the coupled structure to a combined applied voltage and fluid flow. The effect of fluid flow on Reynolds number and fluid vortex frequency as two main parameters in creation of Lock-in phenomenon is studied. In addition to effect of different fluid velocities, response of the micro-beam to different input voltages in the presence of fluid flow is investigated and it is shown that for a given flowing fluid, applied voltage can be used to control the lock-in regime.

During the continuous casting process, Tundish is the last metallurgical actuator in which there will be an opportunity for removal of impurities present in the melt. Therefore, improving of the fluid flow phenomena inside the tundish, including the type of flow pattern, increasing of inclusion residence time in the tundish, decreasing of volume of stagnant fluid and increasing of fluid flow in the rotation, can improve the process of separation of the inclusion and the preparation of clean steel. In the mathematical method, the FLUENT software is used and in the experimental method, by manufacturing of the glass tundish in 1:4 scale and flow physical simulation, the effect of applying the dam in the tundish, as well as the change in the height of the melt on the behavior of the flow has been investigated, and it has been determined that decreasing of the molten height in the tundish increases the separated inclusion from the molten and inclusion residence time in Tundish. Also, by using the dam at inlet nozzle with a tall dam on the sides of the tundish, flow pattern is improved and the inclusion removal will be.

In this paper, the effect of nozzle divergent section geometry on fluid flow and heat transfer within the convergent-divergent nozzle numerically and experimentally is investigated. Axisymmetric supersonic flow simulation for the converging-diverging nozzle is conducted. The flow field is a steady turbulent two-dimensional flow. The working fluid is a combustion product and is considered as a compressible ideal gas. The flow field is simulated using the commercial code FLUENT. The equations are discretized implicitly with the second order of accuracy. In this study, two convergent-divergent nozzles have been analyzed that the divergent part of one is a cone-shaped and the other is bell-shaped. The calculated parameters in the simulation have been compared with the experimental results. Based on the simulation results and the values obtained in the experimental test, the error is less than 4% that is acceptable and appropriate. According to the results, flow simulation accuracy is appropriate.

Heat transfer enhancement is widely applicable in various industries, specifically in heat exchangers. Optimizing of heat transfer in the absence of increased pumping energy will result in increased of total efficiency in different systems. In this paper, forced convection heat transfer and fluid flow of fully developed laminar regime in a horizontal tube under uniform and non-uniform step heat fluxes is investigated experimentally. The effect of uniform, non-uniform increasing and decreasing applied heat fluxes on heat transfer and fluid flow are investigated. The effect of various parameters on heat transfer and fluid flow characteristics in these models are reported. Uncertainty analysis is performed and acceptable maximum of 1.8 percent is acquired. The primary results compared to well-known Shah and London equation for validation and maximum error of 8.5 percent is reported. In the present paper, Energy and exergy are two approach of analyzing. Convection heat transfer coefficient enhancement of 19.3 and 22.3 percent compared with model 1 are reported for model 2 and 3 respectively, in energy analysis. Furthermore, in this paper, exergy analysis is done and irreversibility values of 0.0887, 0.0803 and 0.1037 are reported for model 1, model 2 and model 3 respectively. Finally, it is concluded that the model number 3 is the best way to enhance heat transfer because of the maximum averaged Nusselt number and the minimum entropy generation values