A High Power, High Resolution LDA/PDA System Applied to Gasoline Direct Injection Sprays
✍ Scribed by Graham Wigley; Graham K. Hargrave; John Heath
- Book ID
- 102661874
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 670 KB
- Volume
- 16
- Category
- Article
- ISSN
- 0934-0866
No coin nor oath required. For personal study only.
✦ Synopsis
A new generation LDAaPDA transmitter system has been designed and constructed. The heart of the optical system is a new type of Bragg cell. Advances in laser power handling and symmetrical splitting at high Bragg angles of the shifted and unshifted beams have made it possible to construct a simple yet elegant LDAaPDA transmitter. The optical system integrates the Bragg cell with a laser beam expander to offer variable beam separation and high beam expansion ratios to produce a measurement volume with a high spatial resolution and at high power levels. The transmitter is proving to be a signi®cant contribution to LDAaPDA optical system design and, not only applicable as a research tool for use in ¯ows of a demanding nature but, due to its simplicity, ¯exibility and cost, an asset to teaching.
The LDAaPDA system is being applied to characterise the atomization of fuel by high pressure automotive injectors as found in Gasoline Direct Injection (GDI) engines. Although the PDA system was con®gured to measure two orthogonal velocity components (2D) and size, its operation was not restricted to this con®guration. An analysis of the spray with the PDA system in 1D and size and the LDA system in 2D and 1D con®gurations indicated the complexity of the atomization and break-up processes occurring in the spray. Single-shot imaging was used to study the spatial structure of the spray as a function of time. Use of the light sheet imaging technique alone could lead to false impressions of the atomization process.