What Is the Crossflow Heat Exchanger Effectiveness-NTU Calculator?
The Crossflow Heat Exchanger Effectiveness-NTU Calculator evaluates thermal performance and outlet temperatures of perpendicular-flow heat exchangers.
How Does the Crossflow Heat Exchanger Effectiveness-NTU Calculator Work?
It computes capacity rates, calculates NTU, and solves the analytical Kays-London exponential equation for crossflow effectiveness.
Crossflow Heat Exchanger Effectiveness-NTU Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
Kays & London analytical crossflow formulation for unmixed and mixed fluid channels.
How to Use the Crossflow Heat Exchanger Effectiveness-NTU Calculator
- Enter fluid heat capacity rates (m_dot × c_p) for both streams.
- Specify overall conductance UA in W/K.
- Input hot and cold stream inlet temperatures and select channel mixing configuration.
Step-by-Step Example Calculation
Automotive Radiator Crossflow Sizing
Input Values:
Understanding Your Result
Thermal Effectiveness (ε): Percentage of maximum theoretical heat transfer actually achieved.
Actual Heat Duty: Thermal power exchanged between streams in kilowatts.
Outlet Temperatures: Predicted leaving temperatures for both hot and cold streams.
Factors That Affect the Result
- Increasing UA raises NTU, increasing effectiveness asymptotically toward a limit set by Cr.
- Both-unmixed cores yield 5% to 8% higher effectiveness than mixed cores at equal NTU.
When Should You Use This Calculator?
- Automotive cooling packs, HVAC fan coil units, heat recovery recuperators, and electronic air-to-air cooling.
Assumptions & Limitations
- Assumes steady-state operation, constant fluid specific heats, and negligible external casing heat loss.
Frequently Asked Questions
Calculation Accuracy & Reference Note
Adheres to Kays & London Compact Heat Exchangers (3rd Edition) and Incropera heat transfer principles.