CFD and FE Analysis of a pressure control valve

Our customer Grande Dixence SA is a leading supplier of electrical power and owner of the tallest gravity dam in the world. Several pressure control valves of the hydroelectric power plant had to be inspected in a revision campaign. Due to working conditions different than those used in the design phase 55 years ago, the mechanical behavior of these valves had to be analyzed in order to guarantee the mechanical integrity of the system.
A one way fluid-structure simulation was performed to determine the pressure acting on the valve during the newly defined operating conditions and the structural behavior of the system. The most critical areas to be carefully checked in the revision campaign have been highlighted.

CFD and FE Analysis of a pressure control valve
Streamlines in the fluid domain

Task

Grande Dixence S.A. in Sion (Switzerland) is a leading supplier of electrical power and owner of the Grande Dixence dam in the valaisian Alps, the tallest gravity dam in the world. They have to perform a revision campaign for the maintenance of several pressure control valves (large hydraulic installations that evacuate water in case of overpressure in the pipes). These devices are quite old and the present working conditions have changed since their installation. It is therefore necessary to know the new solicitations of the structure due to water flow. In order to understand this behavior, a coupled one way fluid-structure simulation was performed.

Solution

The geometry was created with ANSYS Design Modeler based on 55 year old construction drawings. The fluid domain, including downstream pipe section was then transferred to ANSYS CFX. The new operating conditions were used to determine the model boundary conditions. With this CFD simulation, the pressure field in the fluid volume and on the internal walls of the ducts was calculated.

In order to assess structural integrity, a Finite Element Model (FE model) based on the structure of the device was built. The concrete surrounding the pipework was also considered. The pressure field obtained from the CFD calculation was used as load condition on the FE model. This allowed calculating the stress field in the structure using ANSYS mechanical.

 

 

CFD and FE Analysis of a pressure control valve
Stress field on the structure due to the effect of fluid pressure

Customer Benefit

With the contribution of CADFEM (Suisse) AG, Grande Dixence S.A. knows the flow behavior in the pressure control valve and structural stress due to the new operating conditions. This allows Grande Dixence SA to identify the most solicited zones of the structure, which have to be carefully checked during the revision campaign.

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CADFEM (Suisse) AG

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