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The purpose of this paper is to design a special automatic redundant robot painting system (RRPS), which can automatically navigate and paint in the long non-regular duct.

The RRPS is designed with three subsystems: a redundant robot, a spraying system and a control and safety system. Based on the modular design theory, the robot falls naturally into a mobile platform, a 4-DOF location mechanism and a 10-DOF manipulator. The restriction of the distance between the links and the duct axis is used to plan the trajectory of the manipulator so that it would not collide with the duct. The restriction model is constructed by minimizing the sum of the weighed distances between the duct axis and the special points.

A fully working prototype system has been developed. Test results show that the minimal distance between the robot joints and duct is 18 mm, and it can finish painting long non-regular ducts at the speed of 12.5 cm/s and the spraying distance of 16 cm. The quality of coating layers is good.

The RRPS was used to paint non-regular rectangular ducts, cylindrical ducts and long non-regular ducts. The feasibility of painting long non-regular duct is proved with the prototype implementation and successful test results.

The RRPS shows a novel solution that is based on the 14-DOF redundant robot design for painting long non-regular ducts which is used in airplane.

To investigate the effect of aspect ratio on the quantitative analogy between developing laminar flows in orthogonally rotating straight ducts and stationary curved ducts

A fractional step method is used to obtain the numerical solution of the governing equations by decoupling the solution of the momentum equations from the solution of the continuity equation. In order to clarify the similarity of the two flows, dimensionless parameters K_LR and Rossby number, Ro, in a rotating straight duct were used as a set corresponding to Dean number, K_LC, and curvature ratio, λ, in a stationary curved duct.

Under the condition that the aspect ratio was larger than one and that the magnitude of Ro or λ was large enough to satisfy the “asymptotic invariance property” the quantitative analogy between the two flows was established clearly.

As the aspect ratio decreased below one, the difference between the secondary flow intensities of these two flows increased, and therefore, the analogy between the two flows was not as evident as that for the larger aspect ratios.

Based on this methodology, the characteristics of the developing flow in orthogonally rotating ducts of higher aspect ratio can be predicted by considering the flow in stationary curved ducts, and vice versa.

The results obtained in this study will suggest an optimal criterion for the application of this approach to the flow similarity analysis in rectangular ducts with arbitrary aspect ratios.

Operational energy use in buildings accounts for 28% of global energy demand. One method to reduce operational energy is upgrading old appliances to more efficient ones. In Australia, the most common residential heating type is reverse-cycle heating, followed by gas heating. This article aims to determine the energy balance resulting from a gas heating upgrade through a life cycle assessment (LCA).

Extensive primary data were collected for operational energy performance of 61 ducted gas heating upgrades. To address the scarcity of data on material composition, one ducted gas heater was deconstructed and assessed in terms of material composition (types and weights). The comparison between embodied energy and operational energy savings allows us to establish whether operational energy savings offset the embodied energy incurred with the upgrade. The end of life stage of the old appliance, as well as the production, construction and use stage of the new appliance were assessed.

The results show that the operational energy savings offset the following impact categories: global warming, ozone layer depletion, aquatic acidification, nonrenewable energy and carcinogens. Only the mineral extraction is not offset by the operational energy savings. The results clearly demonstrate that operational energy savings outweigh the embodied energy and therefore contribute positively to the environment.

This study is the first to focus on the LCA of building services through extensive primary data collection and a focus on a high number of appliances. This supports ongoing energy efficient upgrades in Australia and paves the way for further, similar studies to confirm or disprove these findings in other parts of the world.

AN interesting feature of modern aeroplane design is the growing use of duct systems. The low drag and heat regeneration obtainable from a cooling duct is now an accomplished fact. Ventilation systems for cabin aircraft have been introduced. In the future we may see duct systems used in connexion with the control of the boundary layer. As aeroplane design is improved, new applications of duct systems continue to appear.

Hydrodynamic forces and efficiency of bare propeller and ducted propellers with a wide range of advance ratio (J) and attack angle (θ) are examined. The thrust and torque coefficients and the efficiency are presented and discussed in detail. The present results give a reliable guidance to the improvement of the hydrodynamic characteristics of ducted propellers.

The effect of a duct on the hydrodynamic performance of the KP458 propeller is numerically investigated in this study. Finite volume method (FVM)-based simulations are performed for a wide range of advance ratio J (0 ≤ J ≤ 0.75) and attack angle θ of the duct (15° ≤ θ ≤ 45°). A cubic computational domain is employed in this study, and the moving reference frame (MRF) approach is adopted to handle the rotation of the propeller. Turbulence is accounted for with the RNG k-ε model. The present numerical results are first compared against available experimental data and a good agreement is achieved.

The simulation results demonstrate that the hydrodynamic forces and efficiency increases and decreases with J, respectively, at the same attack angle. In addition, it is demonstrated that the hydrodynamic forces and efficiency are both improved due to the presence of the duct, which eventually leads a better hydrodynamic performance at high advance ratios. It is further revealed that as the attack angle increases, the pressure difference between the suction- and pressure-surfaces of the propeller is also augmented, which results in a larger thrust. The wake field is more uniform at θ = 30°, suggesting that a higher efficiency can be obtained.

The present study aims to investigate the effect of a duct on the KP458 propeller subjected to uniform inbound flow. The relationship between the uniform incoming flow and the attack angle of the duct is mainly focused, and the design of the ducted propellers for any ship hull can be improved according to this relationship.

This paper aims to numerically solve fully developed laminar flow in trapezoidal ducts with rounded corners which result following forming processes.

A two-dimensional model for a trapezoidal duct with rounded corners is developed and conservation of momentum equation is solved. The flow is assumed to be steady, fully developed, laminar, isothermal and incompressible. The key flow characteristics including the Poiseuille number and the incremental pressure drop have been computed and tabulated for a wide range of: sidewall angle (θ); the ratio of the height of the duct to its smaller base (α); and the ratio of the fillet radius of the duct to its smaller base (β).

The results show that Poiseuille number decreases, and all the other dimensionless numbers increase with increasing the radii of the fillets of the duct; these effects were found to amplify with decreasing duct heights or increasing sidewall angles. The maximum axial velocity was shown to increase with increasing the radii of the fillets of the duct. For normally used ducts in hydrogen fuel cells, the impact of rounded corners cannot be overlooked for very low channel heights or very high sidewall angles.

The data generated in this study are highly valuable for engineers interested in estimating pressure drops in rounded trapezoidal ducts; these ducts have been increasingly used in hydrogen fuel cells where flow channels are stamped on thin metallic sheets.

Fully developed laminar flow in trapezoidal ducts with four rounded corners has been solved for the first time, allowing for more accurate estimation of pressure drop.

A numerical study of a quantitative analogy of fully developed turbulent flow in a straight square duct rotating about an axis perpendicular to that of the duct and a stationary curved duct of square cross‐section was carried out. In order to compare the two flows, the dimensionless parameters K_TR=Re^1/4/√Ro and the Rossby number, Ro=w_m/Ωd_h, in the rotating straight duct flow corresponded to K_TC=Re^1/4/√λ and the curvature ratio, λ=R/d_h, in the stationary curved duct flow, so that they had the same dynamical meaning as those parameters for fully developed laminar flow. For the large values of Ro or λ, the flow field satisfied the “asymptotic invariance property”; there were strong quantitative similarities between the two flows, such as in the flow patterns and friction factors for the same values of K_TR and K_TC. Based on these similarities, it is possible to predict the flow characteristics in rotating ducts by considering the flow in stationary curved ducts, and vice versa.

This paper aims to design an optimal shape for an annular S-duct, considering both energy losses and exit flow uniformity, starting from a given baseline design. Moreover, this paper seeks to identify the design factors that affect the optimal annular S-duct designs.

The author has carried out computational fluid dynamic (CFD)-based shape optimization relative to five distinct numerical objectives, to understand their interrelations in optimal designs. Starting from a given baseline S-duct design, they have applied control node-induced shape deformations and high-order polynomial response surfaces for modeling the functional relationships between the shape variables and the numerical objectives. A statistical correlation analysis is carried out across the optimal designs.

The author has shown by single-objective optimization that the two typical goals in S-duct design, energy loss minimization and exit flow uniformity, are mutually contradictory. He has presented a multi-objective solution for an optimal shape, reducing the total pressure loss by 15.6 per cent and the normalized absolute radial exit velocity by 34.2 per cent relative to a baseline design. For each of the five numerical objectives, the best optimization results are obtained by using high-order polynomial models.

The methodology is applicable to axisymmetric two-dimensional geometry models.

This paper applies a recently introduced shape optimization methodology to annular S-ducts, and, it is, to the author’s knowledge, the first paper to point out that the two widely studied design objectives for annular S-ducts are contradictory. This paper also addresses the value of using high-order polynomial response surface models in CFD-based shape optimization.

The dimple is adopted into a pin fin wedge duct which is widely used in modern gas turbine vane cooling structure trailing edge region. The purpose of this paper is to study the effects of dimple depth and duct converging angle on the endwall heat transfer and friction factor in this pin fin wedge duct.

The study is carried out by using the numerical simulations. The diameter of dimples is the same as the pin fin diameter with an inline manner arrangement in relation to the pin fin. The ratio between dimple depth and dimple diameter is varied from 0 to 0.3 and the converging angle is ranging from 0° to 12.7°. The Reynolds number is between 10,000 and 50,000. Results of the endwall Nusselt number, friction factor, and flow structures are included. For convenience of comparison, the pin fin wedge duct with a converging angle of 12.7° without dimples is considered as the baseline.

It is found that the dimples can effectively enhance the endwall heat transfer due to the impingement on the dimple surface, reattachment downstream the dimple and recirculation in front of the pin fin leading edge. By increasing the converging angle, the heat transfer is also increased but with a large friction factor penalty. In addition, the heat transfer enhancement for deep depth cases is 1.57 times higher than that of the low depth case. The thermal performance indicates that the intensity of heat transfer enhancement depends upon the dimple depth and converging angle.

It suggests that the endwall heat transfer in a pin fin wedge duct can be increase by the adoption of dimples. The optimal dimple relative depth is 0.2 with low friction factor and high heat transfer performance.

The purpose of this paper is to design an S‐duct intake for unmanned aerial vehicles (UAVs) applications with good efficiency in a wide range of operating conditions.

A fully‐parametric 3‐D CAD model of the intake was constructed in order to produce different intake configurations, within specific geometric constraints, and to study the influence of geometry variation on efficiency. O‐type blocking methodology was adopted in order to construct the block‐structured mesh of hexahedral elements, used in the simulations. The commercial CFD code ANSYS‐CFX was used to compute the flow field inside the flow domain of each case considered. The Reynolds averaged Navier‐Stokes (RANS) equations are discretized using an implicit, vertex‐based finite volume method, combined with the shear stress transport (SST) two‐equation turbulence model and an automatic wall treatment.

By shortening the axial length the flow separation after the first turning becomes more pronounced and the losses are increasing. For very long ducts the increased internal wall area leads to increased wall friction and, consequently, to increased loss production.

The adoption of Gerlach‐shaped profiles for the design of the S‐duct resulted in a low pressure loss level for the optimal shape, although more uniform distribution of total pressure losses resulted for ducts longer than the optimal one, which should be taken into account in the design process.