The feasibility of laminar flow control technology for future wing is bound to the development of a leading edge high-lift system that complies with the requirements on smooth surfaces to enable maintaining the laminar boundary layer flow. Classical leading edge high-lift devices like slats are not suitable as they introduce disturbances in the very sensitive upper surface leading edge area. Within the European AFLoNext (Active Flow, Loads & Noise Control on Next Generation Wing) project, a full scale HLFC leading edge demonstrator was designed and built that incorporated the vented foldable bull nose Krueger. In summer 2018 this demonstrator was wind tunnel tested in the CIRA Icing Wind Tunnel facility. Within this test the aerodynamic design was verified. Additionally, it was tested whether the Krueger device would need a distinct de-icing system. The contribution summarizes the design of the Kruger device together with the findings from the full-scale wind tunnel test of the Krueger flap configuration.
The feasibility of laminar flow control technology for future wing is bound to the development of a leading edge high-lift system that complies with the requirements on smooth surfaces to enable maintaining the laminar boundary layer flow, such as a Krueger flap. Although in principle the aerodynamic performance of a Krueger flap is known, the unsteady behaviour of the flow during deployment and retraction is completely unknown. This is as even more important as during deployment the Krueger flap is exposed to highly unfavourable positions perpendicular to the flow. To mitigate the risk of unfavourable aircraft behaviour, it is therefore expected that a Krueger flap has to be deflected significantly fast and may trigger unsteady aerodynamic effects. Within the European H2020 project UHURA (Unsteady High-Lift Aerodynamics—Unsteady RANS Validation), currently a wind tunnel test is conducted incorporating the vented foldable bull nose Krueger flap. A wind tunnel model based on the DLR-F15 airfoil has been designed and manufactured that features a part span and a full span Krueger device, which can be actuated at high deflection rates up to 360°/s. First wind tunnel tests have been conducted at the ONERA L1 wind tunnel in Lille in October 2020. The tests included the measurements of internal forces, steady and unsteady pressures, as well as phase-locked Particle Image Velocimetry (PIV) to achieve high quality validation data for comparison with numerical methods.
The effect on corrosion performance of duplex stainless steels after cold bending with and without heat treatment have been widely studied and documented within the refining industry and material producers. Current recommendations exists regarding the minimum bend radiuses allowed for both regular duplex and super duplex stainless steels without the need to perform stress relieve heat treatment that could be detrimental to the material performance if not performed properly. While these recommendations are generalized for refinery services, they are based on conclusions drawn from strain calculations and possible resulting residual stresses found when bending 22% chrome duplex stainless steels or, in the case of 25% chrome duplex stainless steels, the recommendations are based on corrosion data for pitting resistance and chloride stress corrosion cracking testing. However, existing data does not address the suitability of either alloy for sour services in the refining industry in the as-bent condition. This study evaluates the suitability of as-bent super duplex stainless steel UNS-S32750 tubing for refinery sour services by presenting data about the impact of work hardening by u-bending and evaluating these results against current hardness limits per NACE standard MR0103 for super duplex stainless steels. Several seamless .75” diameter super duplex tube samples with two different wall thickness were u-bent to bend radius of 1.5, 2, 3, 4, and 5 times the tube diameter. Hardness data as well as corrosion testing per ASTM G48 method A and NACE TM0177 were recorded and will be presented in order to demonstrate the material’s performance despite residual stresses.
This paper broadly covers the most commonly available non-metallic material options for piping systems handling corrosive fluids. It will describe thermoplastic, thermoplastic-lined metallic, thermoset, thermoplastic lined composite, fiberglass reinforced plastic (FRP) and Engineered Structural Composite (ESC) piping. Corrosion/environmental resistance, thermal expansion, temperature/pressure limits are referenced properties. Relative merits and limitations will be broadly discussed for the purpose of providing a general guideline to non-metallic piping material choices currently available. Discussions of each material technology will be comparative to alternative options. Each material option has unique characteristics of which end users should be aware when making their piping material selections.
Demand variation is a key issue in processed food industry, because demands for processed food products vary daily. The organizations in this situation face challenges to meet customer demand. Their products have a definite shelf life and prone to be obsolete. Obsolete products are totally wastes. So, there exists a producer risk. This study has been conducted with the aim of identifying the root causes of demand variation and its impact on sales volume. For this purpose an exploratory study involving two food processing organizations and their forty eight points of sales had been performed. Each food item has different causes and consequences for demand variation. In this regard, three food items having limited shelf life had been selected to find out the causes of their demand variation. The study identified eleven causes and twelve consequences such as special occasion, duration of shelf life, wrong forecasting and so on. Then some root causes are figured out that dominates over others. The impacts of these causes on sales volume are also shown with six months demand data. The research concludes with the level of impact of the significant causes like price, occasion. Lastly some recommendations are mentioned to minimize those root causes of demand variation.
