Identification of generic errors for effective formative feedback in energy studies thematic area of mechanical engineering

The paper describes the findings from a CETL funded project for the identification of generic errors made by undergraduate students within the thematic area of energy studies in an accredited Mechanical Engineering programme. The idea came from the author’s own experience of teaching in the above thematic area when he observed that the mistakes and errors that the students usually make have some recurrence. Also, the mistakes committed within this subject area are very much theme focused. A systematic qualitative investigation was carried out on the student works available within module boxes. Usually the number of student works kept in a module box is square root of n, where n represents the total number of scripts in a cohort. Four different modules spread over three academic levels (Levels 3,4,5) and for three academic years were available and considered for data collection. Altogether the number of student works that were available was 185. The methodology involved the standard qualitative categorisation approach where the scripts were scrutinised and re-scrutinised in an attempt to identify the commonality of mistakes. After several trials along with critical analysis of the tutor feedback on each individual script, it was possible to identify nine generic errors and mistakes. The frequencies were then counted and data presented in percentages. Interestingly, the findings from this study have later been compared with errors found in examination scripts (of one energy study module) in later years and a broad similarity has been found. Based on such observation, the author regularly uses the findings to remind students of the generic errors and mistakes and highlights the various ways in which they can be minimsed. The feedback from students has been found to be very positive. The results also highlight that similar templates can be produced for other thematic areas of learning such as ‘design’ or ‘mechanics’ within engineering disciplines. Students will greatly benefit from such an in-house list which may serve as a feed-forward template in their future years in the university and beyond

Teaching ethics to engineering undergraduates - lessons learned and a guide for lecturers: perspective from an English University

The issue of ethics within engineering profession has been gaining more and more importance due to globalisation, increasing awareness of sustainability and the fast changing business culture within engineering organisations. As a direct result of such factors the accrediting bodies such as the IMechE and the ABET are very vocal about explicit ethics content in relevant undergraduate engineering programmes. However it is a very challenging exercise to deliver the topic in an effective way due to a number of reasons. First and foremost is the general reluctance of today’s lecturers who themselves were not taught such topics and hence the vast majority are not very keen to consider such ‘softer’ topics very seriously. It is also difficult to accommodate the contents within the engineering curriculum which is already filled with various technical subjects. At the same time, a significant proportion of students find it difficult to relate ethics to real life working environment due to inexperience and hence would consider ‘ethics’ to be ‘not so rigorous’ a subject resulting in poor engagement. The present paper discusses the complete journey of how engineering ethics has been incorporated into an accredited BEng programme in Mechanical engineering. The three steps in course design i.e., breadth and depth of content, detailed planning for effective delivery and assessment and feedback – are all critically discussed by reference to available literature. The author also provides more than one pathway such that the experience may prove useful to the wider communit

Numerical modelling of heat transfer in a tube furnace for steel wire annealing

In order to relieve stresses from cold drawing and to regain ductility, steel wires are annealed in furnaces under prolonged exposure to an appropriate temperature termed as ‘soaking’. This ensures the attainment of the required product quality. Literature suggests that the annealing processes are still determined by trial and error approach due to a lack of standards and also due to the proprietary nature of furnace designs. This paper investigates the heat transfer mechanism in a 12-metre long tube furnace filled with an inert gas and through which a cold-rolled steel wire travels at a specified speed. The length of the furnace is divided into three regions i.e. heating zone, soaking zone and cooling zone of which the heating and the cooling zones are given special attention. The methodology involves the use of Computational Fluid Dynamics by coupling both solid (steel wire) and gaseous zones (Hydrogen or Nitrogen). Radiation has been incorporated via a suitable model and convection taken care of by considering laminar flow of gases. The results suggest that the time needed in the heating zone is influenced by the choices of the surrounding atmosphere, speeds of gas and of the wire. These factors have an impact on the wire drawing speed and eventually on the overall productivity. It is also implied that the proposed numerical method may be used to shorten the ‘soaking’ time and hence to reduce energy consumption. The work demonstrates the usefulness of CFD in understanding and optimisation of the transfer process as well as highlights the challenges associated with numerical results

A review of life cycle assessments of renewable energy systems

A review of life cycle assessments (LCAs) of wind energy published in the past few years are presented in this paper. The aim is to identify the differences of the developed methodologies, in particular, the factors such as methods used, energy performance and influence of uncertainty. Each of the factors is addressed to highlight the shortcomings and strengths of various approaches. Potential issues were identified regarding the way LCA is used for assessing environmental impact and energy performance of wind energy. It is found that the potential of incorporating the quantification of uncertainty in the manufacturing phase has not been studied elaborately. A framework methodology has been proposed in this paper to address this issue

Interaction effects between surface radiation and double-diffusive turbulent natural convection in an enclosed cavity filled with solid obstacles

The work reported here is a 2D numerical study on the buoyancy-driven low speed flow of humid air inside a rectangular cavity partially filled with solid cylindrical objects and whose vertical walls are maintained at 1.2 and 21 oC. This is a case of double diffusion where both temperature and concentration gradients are significant. Detailed calculations were carried out and results compared with reliable data, with the aim of investigating the influence of surface emissivity on heat and moisture transport. The Rayleigh number of the fluid mixture (air and water vapour) based on the height of the vertical wall is found to be 1.45 x 109. In the computations, turbulent fluxes of the momentum, heat and mass were modelled by low-Re (Launder-Sharma) k-ε eddy viscosity model. The effect of radiation has been found to be significant even for the moderate temperature difference of 19.8 oC between the hot and the cold walls with the humid air participating in the radiation heat transfer. Variations of average Nusselt number and buoyancy flux are analysed and profiles of turbulent quantities are studied in order to observe the net effect of the intensity of turbulence. It has been found that a change in surface emissivity influences the humidity distribution and heat transfer within the cavity. It was also observed that during natural convection process the air/water vapour combination results in an increase in the heat transfer as compared to pure natural convection. An increase in heat transfer is observed using thermo-physical materials of higher surface emissivity. It can thus be implied that with the appropriate choice of components, the fluid flow, heat and mass transfer due to natural convection can be increased passively

CFD modelling of cooling air in the NNPB process for glass container production

The aim of this paper is to scientifically understand the operation of the plunger cooling system and quantify the heat transferred from the parison to the plunger during the glass container production process. The paper highlights the results attained and the problems encountered during this investigation. The computational fluid dynamics (CFD) analysis of the cooling air flowing within the plunger cooling tube system used experimental data obtained from both the laboratory test rig and container manufacturing process on the shop floor. Preliminary results attained demonstrated choking together with recirculation of air in some areas along the airflow passage. This confirmed previous findings that areas of excessive tool temperature and rapid tool wear were caused by the ineffective heat extraction. The ineffective heat extraction can be attributed to the poor circulation of cooling air in the plunger. It was concluded that the cooling tube design should be reassessed to improve the airflow in the plunger cooling tube system