Document Details |
|||||
| Name of Department/Committee : | WRD 09 | ||||
|---|---|---|---|---|---|
| Document Number : | WRD 09 ( 26616) | ||||
| Document Title [English] : | Hydraulic Design of Spillway Aerators — Guidelines | ||||
| Document Title [Hindi] : | उत्प्लाव वातकों का हाइड्रोलिक डिज़ाइन — दिशानिर्देश | ||||
| Document Type : | Revision | ||||
| Language : | English | ||||
| Priority : | 3 | ||||
| ICS Code : | 93.160 | ||||
| Date of Project Approval : | 30-07-2024 | ||||
| Standards to be Revised : |
|
||||
| Standards to be Superseded : |
|
||||
Classification Details |
|
| Group : | Civil Engineering Design and Construction |
| Sub Group : | Hydraulic and other related structures |
| Sub Sub Group : | Design, Construction, Planning and Related Standards on Spillways |
| Aspects : | Code of Practice |
| Risk : | None |
| Certification : | Not Certifiable |
| Short Commom Man's Title : | |
| ITCHS Code : | |
| Ministry : |
|
| Sustainable development Goals : | |
| Degree of Equivalence : | Indigenous |
| Identical/Equivalent Standards : | |
| Organization Type: | |
| Sl.No. | Synosis Points | |
| 1 | Spillways and outlets of high-head dams may be exposed to high-velocity flows and the associated destructive phenomenon of cavitation. The extent of cavitation erosion depends to a large extent on the surface finish of the spillway/outlet. As velocity increases above a certain limit, the surface finish required to prevent cavitation erosion exceeds the tolerance to be expected from standard construction practice. In such cases, the spillway surfaces are usually protected from cavitation damage by introducing air near the flow boundary. Devices called aerators which supply the air are located on the spillway floors. | |
| 2 | The procedure outlined in the existing standard (1989) provides the guidelines for preliminary design of aerator for overflow spillway. However, the orifice spillway is a recent development in spillway design for dual purpose of passing the flood and flushing of sediment from the reservoir. The hydraulic characteristics of the orifice spillway are entirely different than the overflow spillway. The hydraulics of orifice spillway changes with varying reservoir levels. The flow is Free flow for reservoir water levels below the roof of the sluice, for higher water levels the flow is orifice flow. Therefore, the design guidelines for aerator on overflow spillway are not applicable to design the aerator on orifice spillway. Aerators on deep-seated orifice spillways with heads more than 50 m are required for mitigating cavitation damage. However, no systematic studies have been reported until now for the aerators on orifice spillways except for a few project-specific studies. | |
| 3 | This standard was first published in 1989. The first revision of this standard incorporates the latest information available for designing the spillway aeration system including need of aerator, types of aerators and its spacing, types of air passages to aerator, jet trajectory calculation, design aspects of aerators and air entrainment mechanism for overflow and orifice type of spillway. The title of the standards has also been updated as ‘hydraulic design of spillway aerators — guidelines’. | |
Timeline Details |
|||||||
|
|
|||||||
|
|||||||
|
|||||||
Stages |
|||||
| Sl. No. |
Stage | Date of Occurence | Remarks | Circulated to | Files |
| 1 | Generation of Document Number | 30-07-2024 | ------- | ||
| 2 | P-Draft Waived | 20-09-2024 | ------- | ||
| 3 | WC Draft | 20-09-2024 | Duration : 60 Days Submitted for HOD approval |
------- | |
| 4 | WC Draft | 20-09-2024 | WC rejected by HOD Remarks: Resubmit with the corrections suggested |
------- | |
| 5 | WC Draft | 07-10-2024 | Duration : 60 Days Submitted for HOD approval |
------- | |
| 6 | WC Draft | 07-10-2024 | WC rejected by HOD Remarks: Resubmit with minor corrections |
------- | |
| 7 | WC Draft | 07-10-2024 | Duration : 60 Days Submitted for HOD approval |
------- | |
| 8 | WC Draft | 07-10-2024 | WC approved by HOD |
WRDC WRD 09, | ------- |