The Augmentation of Flow Boiling Heat Transfer in Tubes(II).
Abstract
The study was oriented toward the fabrication and testing of improved repeatable, high-porosity turbulators for augmenting heat transfer in cylindrical tubes. It was found that the spiral brush insert was superior in repeatability, uniformity, and ease of emplacement to the other types (fiber-filled and knitted wire) considered. Experiments were performed to evaluate the effectiveness of spiral brush inserts in augmenting forced convection heat transfer at high fluxes with water as the fluid under both single-phase and subcooled boiling conditions. Based on equal Reynolds number, use of the spiral brush turbulators resulted in an eightfold increase in heat transfer coefficient over values achievable with comparable empty tubes. Judged on the same criterion, the burnout (critical) heat flux was raised by a factor of three using the spiral brush turbulators. On an equal-pumping-power basis, single-phase heat transfer performance was approximately equal for the two configurations. The results indicate that the spiral brush turbulator method of augmentation is highly advantageous in situations where high heat fluxes must be transferred while, at the same time, restrictions are imposed on available amounts of heat transfer area and coolant. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1971
- Accession Number
- AD0732464
Entities
People
- F. E. Megerlin
- Richard W. Murphy
Organizations
- Raytheon Missiles & Defense