Study on recent progress and advances in air-to-air membrane enthalpy exchangers: Materials selection, performance improvement, design optimisation and effects of operating conditions

2022 ◽  
Vol 156 ◽  
pp. 111941
Author(s):  
A.K. Albdoor ◽  
Z. Ma ◽  
F. Al-Ghazzawi ◽  
M. Arıcı
Keyword(s):  
Performance Improvement ◽  
Recent Progress ◽  
Operating Conditions ◽  
Materials Selection ◽  
Design Optimisation

Fully Parametric High-Fidelity CFD Model for the Design Optimisation of the Cyclic Stagger Pattern of a Set of Fan Outlet Guide Vanes

2009 ◽  
Author(s):  
Andrea Milli ◽  
Olivier Bron
Keyword(s):  
Complex Geometry ◽  
Single Point ◽  
Sensitivity Study ◽  
Operating Conditions ◽  
High Fidelity ◽  
Cfd Model ◽  
Design Optimisation ◽  
Guide Vanes ◽  
High Loss ◽  
Design Variables

The present paper deals with the redesign of cyclic variation of a set of fan outlet guide vanes by means of high-fidelity full-annulus CFD. The necessity for the aerodynamic redesign originated from a change to the original project requirement, when the customer requested an increase in specific thrust above the original engine specification. The main objectives of this paper are: 1) make use of 3D CFD simulations to accurately model the flow field and identify high-loss regions; 2) elaborate an effective optimisation strategy using engineering judgement in order to define realistic objectives, constraints and design variables; 3) emphasise the importance of parametric geometry modelling and meshing for automatic design optimisation of complex turbomachinery configurations; 4) illustrate that the combination of advanced optimisation algorithms and aerodynamic expertise can lead to successful optimisations of complex turbomachinery components within practical time and costs constrains. The current design optimisation exercise was carried out using an in-house set of software tools to mesh, resolve, analyse and optimise turbomachinery components by means of Reynolds-averaged Navier-Stokes simulations. The original configuration was analysed using the 3D CFD model and thereafter assessed against experimental data and flow visualisations. The main objective of this phase was to acquire a deep insight of the aerodynamics and the loss mechanisms. This was important to appropriately limit the design scope and to drive the optimisation in the desirable direction with a limited number of design variables. A mesh sensitivity study was performed in order to minimise computational costs. Partially converged CFD solutions with restart and response surface models were used to speed up the optimisation loop. Finally, the single-point optimised circumferential stagger pattern was manually adjusted to increase the robustness of the design at other flight operating conditions. Overall, the optimisation resulted in a major loss reduction and increased operating range. Most important, it provided the project with an alternative and improved design within the time schedule requested and demonstrated that CFD tools can be used effectively not only for the analysis but also to provide new design solutions as a matter of routine even for very complex geometry configurations.

Recent progress in research on TDLAS fiber optical gas sensor performance improvement

2019 ◽  
Author(s):  
Jiachen Sun ◽  
Jun Chang ◽  
Qinduan Zhang ◽  
Yulei Xie ◽  
Zhiwen Zhang ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Performance Improvement ◽  
Recent Progress ◽  
Sensor Performance ◽  
Fiber Optical ◽  
Optical Gas Sensor

Performance Improvement of a Mixed Flow Turbine Using 3D Blading

2020 ◽  
Author(s):  
Matthew Elliott ◽  
Stephen Spence ◽  
Martin Seiler ◽  
Marco Geron
Keyword(s):  
Performance Improvement ◽  
Design Feature ◽  
Secondary Flows ◽  
Operating Conditions ◽  
Optimized Design ◽  
Mixed Flow ◽  
Performance Improvements ◽  
Blade Shape ◽  
Real Performance ◽  
A Performance

Abstract Mixed flow turbines have reached a level of maturity where iterative performance improvements are very small, with real performance benefits coming from better matching to a given application as opposed to improvements in technology. One ubiquitous design feature of mixed flow turbines used to control stress within the wheel is the radial fibre constraint, wherein blade material is stacked radially outward along the entirety of the blade. While this constraint yields a mechanical benefit, it constrains the aerodynamic design significantly, with the blade shape defined by one camberline. One potential means of realizing a performance improvement is the use of 3D blading, where the blade is not constrained to a radially fibred structure. In such a design, the blade shape could be freely modified to better control blade loading and secondary flows. This study investigated the viability of such 3D blading through optimization of a state of the art mixed flow turbine. An equivalent design was ensured by maintaining the meridional shape and operating conditions of the baseline wheel, thus facilitating a fair comparison between the radial and 3D wheels. The paper details the optimization including an innovative constraint-driven geometry modification tool, experimental validation of performance predictions, and an investigation into why 3D blading facilitated a performance improvement. The optimization process identified a performance improvement across the entire turbocharger operating line. With performance improvements facilitated through a reduction in tip leakage loss, and improved pressure recovery within the conical diffuser. Importantly, the optimized design met targets for mass flow, maximum stress levels, and modal behaviour, through the use of the novel geometry modification process.

Performance improvement of a resonant pressure sensor by means of model based design optimisation

2008 ◽  
Author(s):  
Goran Radosavljevic ◽  
Ljiljana Zivanov ◽  
Andrea Maric ◽  
Laslo Nao ◽  
Walter Smetana ◽  
...  
Keyword(s):  
Performance Improvement ◽  
Pressure Sensor ◽  
Design Optimisation ◽  
Model Based

Helicopter Performance Improvement with Variable Rotor Radius and RPM

2014 ◽  
Vol 59 (4) ◽  
pp. 17-35 ◽  
Author(s):  
Mihir Mistry ◽  
Farhan Gandhi
Keyword(s):  
Performance Improvement ◽  
High Speed ◽  
Power Reduction ◽  
Operating Conditions ◽  
The Other ◽  
Light Conditions ◽  
Large Power ◽  
Low Speed ◽  
Significant Power ◽  
Low Altitude

This paper examines rotor power reductions achievable through a combination of radius and RPM variation. The study is based on a utility helicopter similar to the UH-60A and considers +17% to –16% variation in radius and ±11% variation in RPM about the baseline, over a range of airspeed, gross weight, and altitude. Results show that decreasing RPM alone effectively reduced power at cruise velocities in low-and-light conditions, but the power reductions diminished at increasing altitude and/or gross weight, and in low-speed flight. Increasing radius alone, on the other hand, had greatest effectiveness in power reduction in high-and-heavy operating conditions and at lower flight speeds. When radius and RPM variation is used in combination, minimum RPM is always favored, along with radius increases at increasing altitude and gross weight, and in low-speed operation. At low-to-moderate gross weight, the significant power reductions seen in cruise and at low altitude with RPM variation alone are obtained even at higher altitude, and over the airspeed range, using radius and RPM variation in combination. In high-and-heavy conditions, the combination of RPM reduction and radius increase yields very large power reductions of over 20% and up to 30% over the baseline. Power reduction in low-and-light conditions comes almost entirely from profile power reduction due to RPM decrease. In cruise and high-speed flight, the profile power reductions progressively give way to induced power reductions at increasing gross weight and altitude. At low speeds, reduction in induced power due to increased radius and decreased disk loading dominates.

Performance Improvement of a Hidden Ceiling Fan

2013 ◽  
Vol 479-480 ◽  
pp. 279-283
Author(s):  
Sheam Chyun Lin ◽  
Ming Yuan Hsieh ◽  
Cheng Ju Chang
Keyword(s):  
Flow Pattern ◽  
Performance Improvement ◽  
Horizontal Plane ◽  
Fluid Dynamic ◽  
Air Flow ◽  
Axial Flow ◽  
Critical Factor ◽  
Operating Conditions ◽  
Induced Flow ◽  
And Performance

A hidden ceiling-fan is the new design of embedding and hiding itself deeply into the ceiling floor. This design is different from conventional ceiling-fans or circulating fans that usually without an enclosing housing. The majority part of hidden ceiling-fan is embedded in the ceiling floor; hence the enclosing housing will be needed and be created to surround the axial-flow fan. The housing geometric is critical factor for hidden ceiling-fan because the air flow will pass though the horizontal plane of ceiling floor which the inlet and outlet are almost located at same plane. Consequently, the inappropriate design of enclosing housing will cause inhale-return phenomenon. It affects the induced flow performance of a hidden ceiling-fan. Few studies have investigated fan induced flow and its characteristics in a selected space. In this study, computational fluid dynamic (CFD) numerical simulation and experimental investigation were used to predict and valid the flow pattern with different geometric housing and operating conditions. The results showed that the flow pattern has different features as it leaves the fan downward the floor. The unique inhale-return phenomenon probably happens when inappropriate enclosing housing was designed such as high ring-plate and outlet-inlet ratio. Furthermore, the blockage effect will happen if the blockage distance is to short. In conclusion, thissystematic design investigation on hidden ceiling-fan not only provides the fan engineer’s design ability to avoid the inhale-return phenomenon, but also the predicting capability on the air flow induced characteristics and performance.

Aircraft Engine Performance Improvement by Active Clearance Control in Low Pressure Turbines

2009 ◽  
Author(s):  
Christian Knipser ◽  
Wolfgang Horn ◽  
Stephan Staudacher
Keyword(s):  
Fuel Consumption ◽  
Performance Improvement ◽  
Engine Performance ◽  
Aircraft Engine ◽  
Low Pressure ◽  
Performance Model ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Cooling Air ◽  
Clearance Control

In order to minimize fuel consumption, resulting in reduced operating costs and lower environmental impact, turbofan engines must be of high overall efficiency. The design of the low pressure turbine (LPT) plays a significant role in the development of such engines. During a flight mission changing operating conditions (spool speeds, temperatures, pressures, etc.) cause altering magnitudes of the LPT tip clearance, leading to a decrease in LPT performance. As minimum clearances usually do not occur in steady state cruise condition — the major flight condition concerning fuel consumption — active measures to minimize radial tip clearance (ACC – active clearance control) must be incorporated to achieve a considerable reduction in fuel consumption over the whole flight mission. Actively minimizing radial tip clearance by manipulating the turbine casing requires energy in terms of cooling air (thermal ACC), electrical or hydraulical power (mechanical ACC). The cooling air or the power respectively must be provided by the engine itself, thus partly compensating the benefit gained through the improved LPT behavior. This paper investigates the potential of ACC systems from a whole engine perspective. The approach uses a performance model of a state-of-the-art high bypass turbofan engine with a thermal LPT-ACC system to assess the different benefits and detriments of an enhanced ACC. The overall benefit in TSFC for the simulated engine is compared to measured data of other engines indicating an increase of ACC effectiveness with increasing bypass ratios. To compensate deterioration losses due to single rub-in events, closed-loop controls are required. A tip clearance sensor allows the ACC to adapt to an individual engine. As thermal ACC systems show an optimum benefit with a corresponding optimum ACC cooling air flow, the additional TSFC benefit by compensating deterioration is limited. The achievable overall performance improvement is evaluated for different control loops. Mechanical ACC systems bear the highest potential of eliminating clearance losses, while only minor improvements can be made for thermal ACC systems.

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