Thermoacoustic waves in liquid metal targets for high power Spallation Neutron Sources

The target of the Spallation Neutron Source (SNS) is subjected to bursts of protons lasting less than a microsecond that occur 60 times each second. Each Proton burst deposits thermal energy that causes a pressure distribution in the target. The evolution of this pressure distribution with time must be accurately simulated to facilitate a robust target design. The experimental facility described herein uses a one-dimensional waveguide to create fluid and fluid-structure interactions prototypic of those expected from the pressure wave propagation. This experimental facility permits the collection of data that characterize the interaction of large amplitude pressure waves with various structures. Incident pressure waves exceeding 6.89 MPa (1000 psi) are possible in mercury with pulse widths less than one millisecond. Various materials are used to reflect these waves, and the effect of material properties and surface condition can be examined by observing variations in incident and reflected pressure waves. The facility provides data suitable for validation of the material physics codes used to simulate the SNS target response to the proton pulse deposition. Consequently, data from this experiment allows validation of the material physics code currently employed to simulate the SNS target response.