One of the succeeded methods to enhance the performance of horizontal axis wind turbine (HAWT) is an attaching a winglet to the blades tip. The current paper study the effect of four key parameters that are used to describe the winglet on the performance of wind turbine which are winglet height H%R, cant angle θ, twist angle β, and taper ratio Λ. A five design cases for each geometric parameters were numerically investigated using computational fluid dynamics (CFD) by ANSYS18.1 software, which totally give a twenty different response. A validation of present computational model with reference experimental results successfully carried out with maximum inconsistency of 3%. A mathematical correlation was established from the CFD results and being used in predicting the turbine power for the different winglet geometric parameters. From CFD and mathematical correlation response, the effect of H and θ were greater than β and Λ on the turbine power. The epoxy E-glass unidirectional material was selected for current study to investigate the effect of winglet on blade structure. The power increases by 2% to 30% due to adding winglet to a wind turbine blade. The maximum power increment corresponds to the design case of W6 with H= 8%R, =30°, β = 3°, and Λ = 0.8. Form the structural analysis the addition of winglet changes the stress distribution over the blade, increasing stresses at the blade root, and achieved the transfer of the maximum deformation from the blade tip to the winglet tip.

PurposeFire door should withstand a high temperature without deforming. In the current paper, the challenges of improving the behaviour of the conventional fire door were described using various internal stiffeners in pair swinging-type fire door.Design/methodology/approachThe temperature distribution on the outside door surface was measured with distributed eight thermocouples. Subsequently the internal side was cooled with pressurized water hose jet stream of 4 bar. The transient simulation for the thermal and structure analysis was conducted using finite element modelling (FEM) with ANSYS 19. The selected cross sections during numerical simulation were double S, double C and hat omega stiffeners applied to 2.2 m and 3 m door length.FindingsDuring the FEM analysis, the maximum deformations were 7.2028, 5.4299, 5.023 cm for double S, double C and hat omega stiffeners for 2.2 m door length and 6.57, 4.26, 2.1094 cm for double S, double C and hat omega stiffeners for 3 m door length. Finally, hat omega gives more than three times reduction in the deformation of door compared to double S stiffeners which provided a reference data to the manufacturers.Research limitations/implicationsThe research limitation included the limited number of fire door tests due to the high cost of single test, and the research implication was to achieve an optimal study in fire door design.Practical implicationsAchieving the optimum design for the internal door stiffeners where the hat omega stiffener gives minimum door deformation compared to the other stiffeners was considered the practical implication. The work included two experimental fire door tests according to the standard fire test (ANSI/UL 10C – Positive Pressure of Fire Tests of Door Assemblies) for a door of 2.2 m length with double S stiffeners and a door of 3 m length with hat omega stiffeners, which achieved minimum deformation.Originality/valueThe behavior and mechanical response of door leaf were improved through using internal hat omega stiffeners under fire testing. This study was achieved using FEM in ANSYS 19 for six cases of different lengths and stiffeners for fire doors. The simulation model showed a very close agreement with the experimental results with an error of 0.651% for double S and 1.888% for hat omega.

The investigation documented here aims to contribute to the understanding of secondary flows in modern high-pressure (HP) turbine blade passages. More specifically, it aims to improve the understanding of vortical structures near the endwall with respect to the presence of an upstream cavity that approximates the gap present in actual engines between the rotor and stator of an HP turbine. Further, it aims to assess the viability of using non-axisymmetric endwall contouring to reduce endwall losses, including those generated by the presence of an upstream cavity, using a modern airfoil, at HP turbine representative speeds and at off-design Mach numbers.To attempt to achieve this, a combination of flow measurement, flow visualization, and computational fluid dynamics (CFD) with linear turbine cascades was used. The test matrix consisted of three cases all with one common blade cascade geometry (SL2P). SL2Pwas combined with one of three endwalls: a baseline flat endwall, a flat endwall with a cavity incorporated upstream of the blade row, and a contoured endwall with the same upstream cavity geometry. A combination of pressure probes, pressure taps, and flow visualization were used to collect quantitative and qualitative data in a blow-down type wind tunnel. Complementary CFD studies were also carried out using the commercial CFD code ANSYS CFX.It was found that the presence of an upstream cavity can noticeably alter the structure and the strength of the secondary flow. When compared to the baseline flat endwall, measurements downstream of the trailing edge have shown a substantial increase in the size and strength of the passage vortex. The presence of the cavity also introduces a significant increase in the level of overturning. The secondary kinetic energy increased significantly due to the presence of the cavity, and a major effect on the overall losses was also evident, with the cavity endwall generating up to 14% higher mixed-out row losses ii relative to the baseline flat endwall at the design Mach number of 0.80. It was also found that the endwall contouring design used can successfully lower the losses by altering the structure and the strength of the secondary flows. When compared to the cavity endwall, the contoured endwall results have shown a significant reduction in the size and strength of the counter vortex, accompanied with a large reduction in the secondary kinetic energy in the vortex-vortex interaction regions between oppositely rotating vortices. Overall, the contoured endwall showed a drop of up to 10.7% in mixed-out row losses relative to the cavity endwall, with slightly higher losses than the baseline flat endwall. In assessing the off-design performance of the endwall contouring, the experimental results showed that the endwall contouring can continue to successfully lower the losses at small off-design Mach numbers (Mach 0.69, 0.75, 0.84, and 0.89).The computations did not agree well with the experiment, and overestimated both the losses and the secondary kinetic energy. They predicted alm...