Stagnation Point Flow Of Hybrid Nanofluid Over A Permeable Vertical Stretching/Shrinking Cylinder With Thermal Stratification Effect

Hybrid nanofluid is invented to improve the heat transfer performance of traditional working fluids (water, traditional nanofluid) in many engineering applications. The present study highlights the numerical solutions and stability analysis of stagnation point flow using hybrid nanofluid over a permeable stretching/shrinking cylinder. The combination of copper (Cu) and alumina (Al2O3) nanoparticles with water as the base fluid is analytically modeled using the single phase model and modified thermophysical properties. A set of transformation is adopted to reduce the complexity of the governing model and then, numerically computed using the bvp4c solver in Matlab software. Suction parameter is vital to generate dual similarity solutions in shrinking cylinder case while no solution is found if the surface is impermeable. Two solutions are possible for the assisting and opposing flow within a specific value of the buoyancy parameter. For the shrinking cylinder, Al2O3-water nanofluid has the lowest heat transfer rate than Cu-water and hybrid Cu-Al2O3/water nanofluids. A suitable combination of alumina and copper nanoparticles volumetric concentration in hybrid nanofluid can produce higher heat transfer rate than the Cu-water nanofluid. The execution of stability analysis reveals that the first solution is more realistic than second solution. However, the present results are only fixed to the combination of copper and alumina nanoparticles only and the other kind of hybrid nanofluid may have different outcome

Flow And Heat Transfer Past A Permeable Power-Law Deformable Plate With Orthogonal Shear In A Hybrid Nanofluid

This study concerns the three-dimensional hybrid nanofluid flow and heat transfer due to a deformable (stretching/shrinking) plate with power-law velocity and orthogonal surface shear. The flow due to the shrinking sheet is maintained with the imposition of wall mass suction. The effect of adding Cu and Al2O3 nanoparticles are represented by a homogeneous mixture model with the modified thermophysical properties. Two types of thermophysical properties for hybrid nanofluids are discussed and compared in this interesting work. The three-dimensional model is then, reduced into a relevant set of ordinary differential equations using similarity transformation. The results are generated using the bvp4c solver and presented in the tables and graphs. Duality of solutions are observed in both stretching and shrinking regions, however, only the first solution is proved to be stable and realistic. Surprisingly, the heat transfer rate augments when the power law velocity is used. The hybrid nanofluid with an upsurge of copper volume fraction also reduces the rate of heat transfe

Unsteady Axisymmetric Flow And Heat Transfer Of A Hybrid Nanofluid Over A Permeable Stretching/Shrinking Disc

Purpose: This study aims to analyze the unsteady flow of hybrid Cu-Al2O3/water nanofluid over a permeable stretching/shrinking disc. The analysis of flow stability is also purposed because of the non-uniqueness of solutions. Design/methodology/approach: The reduced differential equations (similarity) are solved numerically using the aid of bvp4c solver (Matlab). Two types of thermophysical correlations for hybrid nanofluid (Type 1 and 2) are adopted for the comparison results. Using correlation Type 1, the heat transfer and flow analysis including the profiles (velocity and temperature) are presented in the figures and tables with different values control parameters. Three sets of hybrid nanofluid are analyzed: Set 1 (1% Al2O3 + 1% Cu), Set 2 (0.5% Al2O3 + 1% Cu) and Set 3 (1% Al2O3 + 0.5% Cu). Findings: The comparison of numerical values between present (Types 1 and 2 correlations) and previous (Type 2 correlations) results are in a good compliance with approximate percent relative error. The appearance of two solutions is noticed when the suction parameter is considered and the unsteady parameter is less than 0 (decelerating flow) for both stretching and shrinking disc while only one solution is possible for steady flow. The hybrid nanofluid in Set 1 can delay the separation of boundary layer but the hybrid nanofluid in Set 3 has the greatest heat transfer rate. Moreover, the inclusion of wall mass suction for stretching case can generate a significant increment of heat transfer rate approximately 90% for all fluids (water, single and hybrid nanofluids). Originality/value: The present findings are novel and can be a reference point to other researchers to further analyze the heat transfer performance and stability of the working fluids

Melting Heat Transfer In Hybrid Nanofluid Flow Along A Moving Surface

The impact and capability of Cu–Al2O3/water nanoliquid as the heat transfer fluid are numerically investigated along a moving surface with melting heat transfer. The reduced differential equations are solved and presented in the figures and tables. The percent error between present and previous numerical values is 0% which supports the model validation. The volumetric concentration of both Al2O3 and Cu nanoparticles is chosen at most 4% to avoid the instability of the nanofluid. The dual solutions are only seen when the external flow and solid surface move in an opposite direction. Remarkably, the use of hybrid nanofluid assists the boundary layer separation in the presence of melting heat transfer. However, the heat transfer rate of Cu–Al2O3/water is inevitably greater than the pure water and Cu–water. An increase in melting parameter reduces the heat transfer rate and accelerates the separation of boundary layer. The stability analysis supports the initial hypothesis from the graphical results that the second solution is unstable

Lecturers’ Method of Teaching Mathematics: Engineering Technology Students’ Perceptions in UTeM

Teaching Mathematics courses at the tertiary level institutions nowadays can be quite challenging especially when the delivery method for the subject matter is known to always be very traditional using the chalk and board. This study examined the Engineering Technology (ET) students’ perceptions of their lecturers’ teaching method for Mathematics courses at the Faculty of Engineering Technology (FTK), Universiti Teknikal Malaysia Melaka, Malaysia (UTeM). A mini survey with quantitative research methods was utilized. 264 second year ET students with different fields of studies at FTK, UTeM, were asked to complete a set of questionnaires administered during the final week of the semester. A questionnaire consists of questions regarding how students perceive their lecturers’ teaching method during the class sessions. From the findings, conclusion has been drawn regarding the students’ perceptions of their Mathematics lecturers in promoting different methods in teaching Mathematics. The result shows that most of the mathematics lecturers incorporated both active and passive teaching methods in teaching of the subject matter

A New Similarity Solution With Stability Analysis For The Three-Dimensional Boundary Layer Of Hybrid Nanofluids

Purpose: The purpose of this study is to implement a new class of similarity transformation in analyzing the three-dimensional boundary layer flow of hybrid nanofluid. The Cu-Al2O3/water hybrid nanofluid is formulated using the single-phase nanofluid model with modified thermophysicalproperties. Design/methodology/approach: The governing partial differential equations are reduced to the ordinary (similarity) differential equations using the proposed similarity transformation. The resulting equations are programmed in Matlab software through the bvp4c solver to obtain their solutions. The features of the reduced skin frictions and the velocity profiles for different values of the physical parameters are analyzed and discussed. Findings: The non-uniqueness of the solutions is observed for certain physical parameters. The dual solutions are perceived for both permeable and impermeable cases and being the main agenda of the work. The execution of stability analysis proves that the first solution is undoubtedly stable than the second solution. An increase in the mass transpiration parameter leads to the uniqueness of the solution. Oppositely, as the injection parameter increase, the two solutions remain. However, no separation point is detected in this problem within the considered parameter values. The present results are decisive to the pair of alumina and copper only. Originality/value: The present findings are original and can benefit other researchers particularly in the field of fluid dynamics. This study can provide a different insight of the transformation that is applicable to reduce the complexity of the boundary layer equations

A Study on the Perceptions and Attitudes of Manufacturing Engineering Technology Student’s about Student-Centred Learning

Student-Centred Learning (SCL) is a method of teaching that puts student at the center of the learning process. The implementation of SCL requires a shift in focus from the lecturer to the student. This method of teaching is looking suitable to the engineering technology student which focusing more on application and implementation compared to engineering student. This study investigated both perceptions and attitudes of 167 students specializing in the area of Product Design and Process Manufacturing Engineering Technology at the Faculty of Engineering Technology (FTK) in Universiti Teknikal Malaysia Melaka (UTeM). Students were given a set of questionnaires during one of the classes. From the findings, conclusion has been drawn regarding the SCL approach to support teaching and learning. The result shows that the students’ self-directed learning readiness and a positive perception toward SCL should be encouraged. At the same time, the role of lecturers is very important to ensure the successful of the SCL approach in teaching and learning is taking place and thus, will lead to a change in the perceptions and attitudes of the students towards SCL

Attitudes towards Motivation in Mathematics: A Case Study on Engineering Technology Students at FTK, UTeM

The aims of this study were to understand and examine the Engineering Technology (ET) students’ attitudes towards their motivation while learning mathematics during their studies at the Faculty of Engineering Technology (FTK), Universiti Teknikal Malaysia Melaka (UTeM). In this study, a set of questionnaire from a previous study by Galbraith and Haines (1998) was utilized, which included questions on the students’ attitudes towards their motivation while learning mathematics. A total of 332 second year ET students at FTK, UTeM were requested to complete the questionnaire during the final week of semester two of the 2013/2014 session. From the findings, a conclusion was drawn regarding the ET students’ attitudes towards motivation while learning mathematics. The result showed that most ET students had positive attitudes towards their motivation while learning mathematics during their studies at FTK, UTeM

Engineering Technology Students’ Attitudes towards Engagement in Mathematics

The objective of this study is to understand and examine the attitudes of Engineering Technology (ET) students towards engagement in mathematics during their studies at the Faculty of Engineering Technology (FTK), Universiti Teknikal Malaysia Melaka (UTeM). In the study, a set of questionnaire that covers the questions on the students’ attitudes towards engagement in mathematics was utilized. A total of 332 second year ET students at FTK, UTeM were requested to complete this set of questionnaire during the final week of semester two for 2013/2014 session. From the findings, a conclusion has been drawn regarding the attitudes of the ET students towards engagement in mathematics. The result showed that most of the ET students were very engaged in mathematics, and their engagement was more on behavioral types during the learning process of mathematics in class at FTK, UTeM