Articles with tag: "evaporation"

1. NACA-TN-3024-revisited

   "evaporation losses are ... very small (less than 1 percent) in the case of smaller obstacles (of icing-rate-measurement-cylinder size)."

   "Maximum Evaporation Rates of Water Droplets Approaching Obstacles the Atmosphere under Icing Conditions" Evaporation calculations ¹

   

   Summary

   Less that 1% of drops evaporate approaching an obstacle for most cases.

   Key points

   1. Equations are detailed for the evaporation of water drops approaching an obstacle.
   2. The equations were coded into a python program.
   3. Less that 1% of drops evaporate approaching an obstacle for most cases.
   4. A water drop that approaches on the stagnation line but does not impinge is predicted to evaporate away.

   NACA-TN-3024 was reviewed previously, herein we will concentrate on comparing our own code to the results in NACA-TN-3024.

   Abstract

   When a closed body or a duct envelope moves through the atmosphere, air pressure and temperature rises occur ahead of the body or, under ram conditions, within the duct. If cloud water …

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2. AEDC1DMP

   "The third part of the study comprised some numerical computations of two-phase, dilute, air and entrained water particle flows, using a new version of the AEDC one-dimensional, multiphase flow code, AEDC1DMP."

   

   The AEDC 1-Dimensional Multi-Phase code (AEDC1DMP) and the iads1dmp

   Abstract

   The AEDC1DMP calculates the water drop speed and evaporation in an icing wind tunnel. The AEDC1DMP is described in "Second Report for Research and Modeling of Water Particles in Adverse Weather Simulation Facilities" ¹. AEDC is the Arnold Engineering Development Complex, formerly the Arnold Engineering Development Center.

   1.0 INTRODUCTION TO THE RESEARCH
   This report describes a continuation of research into the modeling of water particle freezing for application to adverse weather simulation facilities. The research was initiated in FY1996 to investigate the physics of freezing of submillimeter supercooled water particles or droplets in both natural and artificial or simulated adverse weather environments. The first phase of the research …

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3. Let's Build a 1D Water Drop Trajectory Simulation

   

   "The discrepancies are of the magnitude to be expected from ... the step by step integration". ¹

   Let's build a 1D water drop trajectory simulation

   Summary

   Water impingement values on a cylinder are calculated with step-by-step integration.

   Key points

   1. 1D equations of motion were implemented.
   2. Results agree well with the minimum drop size required for impingement.
   3. Water drops may contact the cylinder at very low K values.
   4. The methods appears accurate enough to use for other applications.

   Discussion

   We are going to start with a one dimensional simulation along a single line, the stagnation line of flow around a cylinder, y=0 in the figure above.

   We will implement the equations of motions for a drop around a cylinder from "Mathematical Investigation of Water Droplet Trajectories" ¹.

   Readers unfamiliar with "Mathematical Investigation of Water Droplet Trajectories" may wish to review it before proceeding further herein, especially to be familiar with the …

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4. Super-Cooled Water Droplets in Rising Currents of Cold Saturated Air

   "It is possible to develop this theory to cover also growth of water droplets during the adiabatic expansion of a rising mass of saturated air."

   

   Irving Langmuir, "Super-Cooled Water Droplets in Rising Currents of Cold Saturated Air"

   Summary

   Evaporation and condensation rates on water drops are calculated.

   Key Points

   1. A theory of water drop growth by condensation in the atmosphere is developed.
   2. The drop size measurement by oiled-slide and multicylinder instruments is improved.
   3. The evaporation rates of stationary water drops is analyzed.

   Abstract

   As this is an extensive work (130 pages), and as Langmuir did not provide an abstract or introductory summary, we will begin with the Langmuir's conclusions as a summary.

   Summary of Main Conclusions of Part I to April 1, 1944

   Before analyzing the new data it is desirable to summarize the main conclusions reached from the foregoing parts of this report:

   1. The Glauert theory of the deposition …

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