Experience: Thermal Simulation and Modeling

DESIGN

ANALYSIS AND TESTING

OPERATIONS

EXPERIENCE

THERMAL SIMULATION AND MODELING

S&V Siu Associates improved a client's RF Ablation Model.

ISSUE

Our client presented us with data showing an unacceptably large variation in RF ablation dosage from their device. Variations in measured dosage were as high as 25%. It was unclear whether there were issues with the measurement or whether there were issues with variability in the ablation device. Our initial task was to examine the data and measurement system to determine the accuracy of the measurements.

ROOT CAUSE ANALYSIS

We inspected the system and analyzed the methodology to determine the RF dosage from our client's device. The client used a calorimetry type system, and we determined that a lack of understanding of the thermal behavior of the system was the root cause of the large variations in the measurements. Effects from the lab environment as well as thermal loading effects (heating/cooling history) were not sufficiently taken into account.

IMPLEMENT SOLUTION

To provide a solution for our client a computer model was first constructed to simulate the thermal behavior of the system. The simulation results were compared to actual real time thermal measurements of the client's calorimeter and showed good agreement. The simulation was then used to help design a better calorimeter. The new design was implemented and reduced the measurement uncertainties from >25% to less than 5% which then enabled our client to more accurately access the variability in their ablation device.