The influence of various inlet geometries on mixed convection flow of ethylene glycol in a backward facing step

Numerical simulations of two dimensional laminar mixed convection flow over backward facing step with different inlet geometries in a duct is investigated by using finite volume method. The wall down downstream of the step is kept at a temperature of 330K and constant heat flux of 500W/m2, while the other walls that form the other side of the duct are thermally insulated. Ethylene glycol is used as working fluid and three types of barrier which are triangular, parallelogram and semicircle are carried out to compare with a simple entrance of backward facing step. The Reynolds number was in the range of 50Re200 and fluid temperature is 300K at the inlet of the channel. Parallelogram inlet has the highest average velocity in all sections and highest average Nusselt number over downstream. Also triangular inlet has the highest shear stress all over the downstream of the duct and cause to make a highest skin friction coefficient

Numerical study on heat transfer of turbulent flow in a channel with composite arrangement obstacles

Forced convective heat transfer of turbulent flow in a two-dimensional channel mounted triangular and trapezoidal obstacles in upper wall and bottom wall arranged with periodic grooves is numerically studied. Continuity, momentum and energy equations are discretized with second order upwind method is applied to solve the equations. (RNG) k-ε model is implemented to predict the thermo-hydraulic performance of the flow. A thick of 3mm made up by aluminum is implemented for channel walls that the bottom and upper walls are heated with a uniform heat flux. The thermo-hydraulic effects of shapes and positions of obstacles mounted on upper wall referred to the bottom ribbed and grooved wall of the channel as well as its thermal enhancement factorare tested in a Reynolds number range of 3000 to 5000 with engine oil as working fluid. The numerical results demonstrate that combination of trapezoidal obstacles arrays of the upper wall placed against of ribs array of the bottom wall reveals highest thermal enhancement factor due to trapezoidal obstacles with increasing height in flow direction not only lead the flow to the bottom grooved wall but also the flow osculate surface of the obstacle and restart the thermal boundary layer with lowest friction factor compared to other cases

Effect of vertical baffle installation on forced convective heat transfer in channel having a backward facing step

In this study, forced convective heat transfer is considered in channel over a backward facing step having a baffle on the top wall. Four different geometries with different expansion ratios and different type of baffles are numerically investigated. The study clearly shows that the geometry with expansion ratio 2 and solid baffle has the highest Nusselt number compared to other geometries. Considering both Nusselt number and skin friction coefficient for all four geometries clearly illustrated an increase in average Nusselt number by increasing the expansion ratio. This study clearly shows that mounting a slotted baffle at the top wall instead of a solid baffle caused a decline in average Nusselt number. It is also found that for geometry with expansion ratio of 3 and a slotted baffle on the top of the channel, skin friction coefficient in both bottom wall and step wall has its minimal compared to other geometries

Exploring the Affordance of Distance Learning Platform (DLP) in COVID19 Remote Learning Environment

2020, Springer Nature Switzerland AG. Higher Education has been facing the dilemma of the preferred delivery method for over two decades. COVID19 pandemic in 2020 made the need for further exploration of the same even more imperative. Although the urgency of events did not leave much time for policymakers and educators to decide, it did inspire the authors of this article to analyse the affordances of Distance Learning Platform (DLP), and the ways students perceived the online learning due to current uncertain circumstances. Students as critical stakeholders in the learning process were on the receiving end of the decisions taken to facilitate distance learning. The focus of this study was to understand students\u27 experience of using the Distance Learning Platform (DLP) in a crises-induced environment at a university in the United Arab Emirates. A sample size of 60 undergraduate students who took academic study skills classes was used to collect data. Students were asked to reflect on their experience of distance learning, and the data were analysed to understand the students\u27 preferences of their study method while enabling them to recognise their cognitive skillset. The data indicated reasons behind students\u27 preferences of the preferred delivery method