Analysis and Comparison of the Temperature Differences between

Concurrent and Countercurrent Flow in Concentric Tube Heat Exchangers

By Dave Onarheim

MANE-6980 Engineering Project

Spring 2010

MANE-6980 Project- Concentric Tube HX

Forced convection heat transfer is caused by fluid flow of different temperatures passing parallel to each other separated by a boundary (pipe wall)

Flow can be in the same direction (parallel) or in the opposite direction (countercurrent)

Problem Description

The overall objective is to determine the max temperature difference in cases for both laminar and turbulent flow for a variety of flow rates and inlet temperatures

Flow will be considered fully developed and incompressible The cooling medium will be water and the working fluid oil Viscosity and density of the fluids will remain constant Specific heat and overall heat transfer coefficients are also assumed

to remain constant

Methodology and Expected Outcome

Use COMSOL multiphysics to develop models of laminar and turbulent flow

5 models will be done for both laminar and turbulent flow: normal flow in a pipe, parallel flow, countercurrent flow, and fouled surfaces for parallel and countercurrent types of HX

Mass flow rate as well as inlet temperature will be varied Results will be analyzed using COMSOL and exported to Excel as

needed Hand calculations will be done to use as a cross check The countercurrent flow is expected to yield the larger temperature

difference in both fouled and unfouled HX surfaces

Milestones/Deadlines

2/05/10:Project proposal due, Brief Presentation of proposed work 2/10/10:Complete research, Document results 2/17/10:Complete first model of laminar flow in a pipe, Complete second model of laminar flow for

2 concentric pipes (parallel flow HX) and document results 2/24/10:Complete third model of laminar flow for 2 concentric pipes (countercurrent flow HX),

Document results 2/26/10:First progress report due 3/03/10:Complete fourth and fifth models of laminar flow for 2 concentric Pipes (fouled HX

surface), Document results 3/10/10:Complete first model of turbulent flow in a pipe, Complete second model of turbulent flow

for 2 concentric pipes (parallel flow HX) and document results 3/17/10:Complete third model of turbulent flow for 2 concentric pipes (countercurrent flow HX),

Document results 3/19/10:Second progress report due, Comprehensive presentation of work 3/24/10:Complete fourth and fifth models of turbulent flow for 2 concentric Pipes (fouled HX

surface), Document results. Gather data, ensure all models and plots needed are obtained 3/31/10:Complete rough draft of paper, Complete peer editing 4/9/10: Final draft of project 4/21/10:Final report due, Comprehensive presentation of work

Questions?