THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS Film-Cooling from Holes with Expanded Exits: A Comparison of Computational Results with Experiments

Abstract A 3D Navier-Stokes code, together with the standard k-c model with wall function approach. was used to investigate the flowfield in the vicinity of three different single scaled-up film-cooling holes. The hole geometries include a cylindrical hole, a hole with laterally expanded exit, and a hole with forward-laterally expanded exit. Comparisons of numerical results with detailed flowfield measurements of mean velocity and turbulent quantities are presented for a blowing ratio and density ratio of unity. Additionally, experimental data for different blowing ratios and a density ratio of about two are taken to perform validation of the code for adiabatic film-cooling effectiveness prediction. Results show that for both the round and the expanded hole geometries the code is able to capture all dominating flow structures of this jet in crossflow problem. However, discrepancies are found when comparing the flowfield inside the hole and at the hole exit. In particular, jet location at the hole exit differs significantly from measurement for the expanded hole geometries. For the adiabatic film-cooling effectiveness, it is shown that for round and expanded hole exits the intensity of the shear regions and the source of turbulence, respectively, have a strong influence on the predictive capability of the numerical code

Enhancing Livelihood Security through the National Employment Guarantee Act Toward Effective Implementation of the Act

The National Rural Employment Guarantee Act of 2005 is a major development in the history of poverty reduction strategies and rural development policies in India. Though the successful passage of the Act is due to the long struggle by NGOs, academics, and some policymakers, its successful implementation is a much bigger challenge. Effective implementation of the Act requires that labor-intensive works be planned for the needy poor on a continuous basis; that the right kind of assets are undertaken to promote the development of the local/regional economy; and that the labor-absorbing capacity of the mainstream economy be raised and assets maintained well and used productively to generate benefits for the poor, as well as to promote pro-poor economy growth. The past experiences of wage employment programs in India, however, suggest that there are several challenges ahead. These include strengthening the planning component of the program, particularly planning for infrastructure and natural resource management; coordination and conversion of the Employment Guarantee Scheme with ongoing programs; ensuring supply of labor on EGS works; promoting equity in the ownership of the assets; and using assets to improve the employment generation in the long run. This paper discusses these challenges and observes that the Employment Guarantee Act should not be treated as one more poverty alleviation program, but should be seen as an opportunity to eradicate the worst kind of poverty and to empower the poor and promote pro-poor growth of the Indian economy