Articles with tag: "water catch"

Computer Impingement Analysis Tools Examples

LEWICE 1990 Figure 4.2. Definition of total and local collection efficiency.
from Users Manual for the NASA Lewis Ice Accretion Prediction Code (LEWICE) (1990 version) ntrs.nasa.gov

Prerequisites

You need to complete the Aircraft Icing Handbook Water Catch Examples.

You need to select a computerized tool to work with. See Analysis Toolset for obtaining LEWICE, and some other options.

Aircraft Icing Handbook Example 2-2

Example 2-2
This example illustrates the estimation of the impingement parameters E, β, h, Su and SL using graphical data (reference 2-12). The graphical data is all presented with Ko as the independent variable. Much data is available in this form.

The conditions of Example 2-1 for a NACA 0012 airfoil are assumed: thus Ko = 0.05. It also is assumed for simplicity that the angle of attack, α, is 0 degrees. From figure 2-11, E, the total impingement efficiency, is estimated to be 0.23 for these conditions. So about 23 percent of the water …

Aircraft Icing Handbook Water Catch Examples

Graph of water catch efficiency Em versus Ko for a cylinder.
Public domain image by Donald Cook.

Introduction

The "Aircraft Icing Handbook", DOT/FAA/CT-88/8-1, provides examples of two-dimensional water catch rates for the ice accretion process.

The Handbook uses something like "US Customary" or "Engineering" units in the calculations. This may limit the direct reuse of the equations.

These calculations can be reasonably accomplished through hand calculations, or a spreadsheet. However, they can be important "stepping stones" to build more complex capabilities.

Code written in the python programming language is available via github.com/icinganalysis, file "intermeadiate/basics_water_catch_calculations.py" (and associated files) for the solutions, under the LGPL license. Internally, the code uses (mostly) SI units (see A Brief Digression on Unit Systems for details). There are unit conversion functions in the python code. Values here are reported in the handbook units.

You are encouraged to run the provided code, or to start building your own library of such …