Advanced Instrumentation for Non-Nulling Stack Velocity Testing

Industrial facilities, manufacturing plants, and electric power plants that burn fossil fuels exhaust the combustion products to atmosphere through their smokestacks. Stack pollutant emissions are quantified using manual testing methods developed in the 1960s, which are prone to error if non-axial flow exists in a stack.Recently, NIST has been working on an improved technique of performing 3D flow testing for smokestacks which will greatly reduce the complexity, duration, and potential for human-error. Advanced data acquisition systems and software are required to accommodate the NIST test methodology. These systems must be highly accurate but also able to operate in potentially harsh environmental conditions since the testing is conducted year round on outdoor platforms of smokestacks.This project proposes to develop an advanced data acquisition system suitable for the NIST “non-nulling” test technique. The system requires highly accurate pressure sensors, working collectively to acquire data from multiple velocity probes. In addition, the system must have capability to purge the probe pressure lines of any debris or condensation that would degrade accuracy, operate in harsh weather, and provide a straightforward interface to an operator. The system will thus involve both advanced instrumentation along with custom software to follow the NIST “non-nulling” protocol.