Thermal Performance & Fluid Dynamics

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Thermal Performance & Fluid Dynamics

DEI has significant expertise in modeling and analysis of thermal performance and fluid dynamics in industrial heat exchange equipment, and has authored a number of industry references on these topics, including chapters of Thermal Performance Degradation and Heat-Transfer Fouling and EPRI TR-110018 on thermal performance analysis methodologies. DEI serves as a technical consultant to the EPRI Steam Generator Management Program and EPRI technical committees on a number of topics, including: Plant Engineering, Dispersants and Filming Amines / Filming Products. Our thermal performance and fluid dynamics expertise includes:

  • Thermal performance optimization in power systems
  • Computational fluid dynamics (CFD)
  • Multi-phase flow
  • Fluid-structure interaction
  • Fluid-induced material degradation issues, such as fracture mechanics, turbulence-driven thermal fatigue, flow-accelerated corrosion and erosion/corrosion
  • Multi-physics modeling, such as combined neutronics and thermal hydraulic simulations in a nuclear reactor core
  • Effects of corrosion product deposition on thermal efficiency in heat exchange systems, including steam generators and balance-of-plant heat exchangers
  • Economic analysis to optimize the timing and frequency of inspection, maintenance and repair/replacement activities


Chuck Marks, Ph.D.

Jack Dingee, Ph.D.


Steam Generator Thermal Performance Assessment

Utility Consulting: DEI regularly performs consulting studies to assist utilities in assessing steam generator (SG) thermal performance losses due to corrosion product accumulation, and predicting future rates of thermal performance degradation. In an example study for a US utility, DEI provided the following assistance and insights:

  • Assessment of current levels of SG fouling and thermal efficiency loss
  • Prediction of future thermal performance losses, including probabilistic assessment of when thermal efficiency losses would begin to reduce power output in the absence of corrective measures
  • Economic analysis of candidate measures to restore and mitigate thermal performance losses, including identification of optimal timing and application frequency
  • Updated analysis to assess the thermal performance recovery achieved through implementation of recommended corrective maintenance activities and subsequent rate of re-fouling observed

The analyzed units achieved an 8-10 psi recovery in steam pressure by implementing maintenance activities recommended by DEI and avoided losses in power output by increasing their thermal performance margin relative to the valves-wide open condition.

Thermal Fatigue Modeling in Reactor Coolant Piping

EPRI Research Program: Nuclear plants have experienced cases of material degradation and primary water leaks due to turbulence-driven thermal fatigue. DEI has supported a multi-year EPRI research program to develop high-resolution industrial models for thermal fatigue using computational fluid dynamics (CFD) and other numerical solvers. DEI efforts in this area have included:

  • CFD modeling of residual heat removal system mixing tees coupled with thermal, structural, and fatigue analysis
  • CFD modeling of turbulent swirl penetration in normally stagnant branch lines, including comparison to semi-empirical industrial models and experimental validation using high-resolution particle image velocimetry
  • Inverse system analysis to determine piping in-leakage and cross-flow using custom Python codes and field measurements
  • Assessment and modeling of craze crack growth and arrest

The efforts above benefit the industry by reducing the risk of unplanned outages due to thermal fatigue degradation, while reducing O&M costs through optimized inspection intervals.

Analysis of Sonic Jet Transients in Waste Treatment Facility

CFD Modeling & Experimental Validation: The integrated waste treatment unit (IWTU) in Idaho uses sonic gas pulses to backwash and regenerate gas filters operating at high temperature. Optimization of the gas pulse system and downstream Venturi block geometry is needed to ensure the desired performance is achieved, maximizing filter regeneration. DEI has provided the following technical consulting and support for this effort:

  • Transient computational fluid dynamics (CFD) modeling of the sonic jet, including flow into and through the porous filter elements
  • Design and construction of a test rig for molecular tagging velocimetry (MTV) acquisitions to validate CFD modeling results
  • Lumped-parameter modeling of the backpulse gas volumes from an upstream reservoir to a choked flow nozzle using a custom transient Python solver

DEI modeling and experimental validation has supported improved understanding of the design and operation of both pilot-scale and full-scale plant conditions, and optimization of the process gas filters for reliable long-term operation.