Pre-swirl Research Papers - Academia.edu (original) (raw)

Enhancing heat transfer surface are used in many engineering applications such as heat exchanger, air conditioning, chemical reactor and refrigeration systems, hence many techniques have been investigated on enhancement of heat transfer rate and decrease the size and cost of the involving equipment especially in heat exchangers. One of the most important techniques used are passive heat transfer technique. These techniques when adopted in Heat exchanger proved that the overall thermal performance was improved significantly. This experimental works can be taken by researchers on Augmentation Technique such as Twisted Tape. So, Researchers tried to increase the effective surface area Contact with fluid to increases the heat transfer rate in the heat exchanger. We tried to enhance the Heat transfer rate with the help of Twisted Tape insert with Wiry Metallic Sponge and find out the effect of Metallic Wiry Sponge on Flow of Fluid.

- by
- •
- Heat Exchanger, Vortex dynamics, Pre-swirl, Tube

Pre-and post-swirl fins-based energy-saving devices (ESD) are designed to improve the propulsive performances of a twin-screw ship. To this aim, BEM and RANSE calculations are employed. Depending on the application, a simple actuator disc model (post-swirl) with radially varying load or a combined BEM/RANSE method for self-propulsion prediction (preswirl) are required. Both the approaches are included in a framework for a design by optimization, where systematic variations of the ESD geometry are used to explore the design space and maximize the energy-saving effect of the devices. Considering the particularity of the case selected for the study, results show encouraging improvements that reach a promising 5% in the case of the combined action of both devices.

- by Stefano Gaggero
- •
- Naval Engineering, Naval Architecture, Optimization, Energy saving systems

Pre-swirl stator concept is proposed in this paper to improve the overall efficiency of Horizontal Axis Tidal Turbine (HATT). Numerical simulation of HATT with and without pre-swirl stator
concept is conducted in different Tip Speed Ratio (TSR). A three bladed tidal turbine is numerically modelled and solved by a three-dimensional finite volume solver. Turbine model is studied using a timeaccurate Reynolds-Averaged Navier-Stokes (RANS). The transient rotor-stator model with sliding mesh technique is used. The power coefficients of a HATT without pre-swirl stator are predicted numerically and validated by existing experimental data. It has been found that the use of pre-swirl stator can improve
the velocity field around the turbine leading to an increase of the overall turbine efficiency by about 13% in specific TSR.

- by Islam Amin
- •
- Renewable Energy, Pre-swirl, Horizontal Axis Tidal Turbine

This paper describes the modelling of direct transfer pre-swirl cooling air delivery systems using a library of secondary air system components developed in an object-oriented simulation environment. The modelling accounts for the flow through the stationary pre-swirl nozzles and rotating receiver holes, the moments and convective heat transfer from the chamber surfaces and the mixing of seal flows. The model is validated against measured data from experimental rigs representative of aeroengine conditions. The modelling approach allows for rapid evaluation of alternative component designs for optimum overall performance at system or engine level.

- by Alexios Alexiou
- •
- Delivery System, Convective Heat Transfer, System performance, Pre-swirl

"This paper describes the modelling of direct transfer pre-swirl cooling air delivery systems using a library of secondary air system components developed in an object-oriented simulation environment.
The modelling accounts for the flow through the stationary pre-swirl nozzles and rotating receiver holes, the moments and convective heat transfer from the chamber surfaces and the mixing of seal flows.
The model is validated against measured data from experimental rigs representative of aero-engine conditions.
The modelling approach allows for rapid evaluation of alternative component designs for optimum overall performance at system or engine level."

- by Alexios Alexiou
- •
- Pre-swirl, PROOSIS, Engine Performance Modelling, Secondary Air System

A design method for pre-swirl stators energy saving devices, using a combined BEM-RANSE approach, is proposed. RANSE calculations, using actuator disks, are employed to provide the required thrust and the effective wake to an unsteady Boundary Element Method through which the rate of revolution of the propeller and its averaged performance in self-propulsion are evaluated. An automatic variation of the pre-swirl geometry, driven by an optimization algorithm that operates on the parameters defining the device, realizes an automatic "try-and-error" process, which is used as a design tool for the maximization of the energy saving effect. Results obtained for different numbers of stator fins show outstanding improvements, up to a reduction of the required shaft power of about 8%.

- by Stefano Gaggero and +1
- •
- Naval Engineering, Naval Architecture, Computational Fluid Dynamics, Optimization

This paper describes the modelling of typical secondary air system elements such as rotating orifices, seals and flow passages with heat and work transfer from the surrounding surfaces. The modelling is carried out in an object-oriented simulation environment that allows the creation of different configurations in a simple and flexible manner. This makes possible to compare the performance between different designs of individual components or complete secondary air systems as well as integrate them directly in whole engine performance models. The modelling is validated against published experimental data and computational results. An example of implementation in an engine model is also presented.

- by Alexios Alexiou
- •
- Performance Modeling, Rotating Cavity, Pre-swirl, PROOSIS