Accession Number:

ADA181372

Title:

Environmental & Water Quality Operational Studies: Improvement of Hydropower Release Dissolved Oxygen with Turbine Venting.

Descriptive Note:

Final rept.,

Corporate Author:

ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS ENVIRONMENTAL LAB

Report Date:

1987-03-01

Pagination or Media Count:

109.0

Abstract:

This report summarizes various in-lake, in-structure, and downstream techniques to enhance the dissolved oxygen concentration of hydropower releases. In-lake and in-structure techniques appear to be the most applicable for Corps of Engineers projects because of the large discharges of most hydropower projects. Of these, the in-structure techniques, particularly turbine venting, appear very attractive considering cost and degree of improvement. Tests were conducted at the Clarks Hill Dam powerhouse to evaluate various aspects of turbine venting and thereby provide a data base to develop predictive and design capabilities for turbine venting systems. Test results indicated that, at most, the oxygen deficit in the penstock could be reduced by about 30, i.e., if the penstock oxygen deficit is 8.0 mgl, then, at most, about 2.4 mgl of oxygen could be absorbed into the release flow. Two reaeration processes that contributed to the overall oxygen transfer were observed a due to the turbulence in the tailrace area and b due to the air bubbles vented through the turbine as they traveled through the draft tube. A numerical computer model was developed that included the impact of the changes in thermodynamic pressure state as the bubbles passed through the draft tube. By developing the pressure time history, the increased potential for oxygen transfer due to the increase in hydrostatic pressure was included in model formulation. Good agreement was obtained in comparing model predictions and oxygen uptake data from previous tests at Clarks Hill.

Subject Categories:

  • Electric Power Production and Distribution

Distribution Statement:

APPROVED FOR PUBLIC RELEASE