Subtopic: Functional requirements, principles of working, construction and operation of manual, animal, tractor and renewable energy operated equipment for tillage, sowing, planting, fertilizer application, inter-cultivation, spraying, mowing, chaff cutting, harvesting and threshing
Question Statement:
Laser diffraction analysis of the droplet spray spectrum from an agricultural flat-fan nozzle yielded the following cumulative volume diameters: $D_{10} = 120\text{ }\mu\text{m}$, $D_{50} = 250\text{ }\mu\text{m}$ (Volume Median Diameter, VMD), and $D_{90} = 410\text{ }\mu\text{m}$. The Relative Span Factor ($RSF$) of the droplet size spectrum is ________ (round off to 2 decimal places).
Answer Key:
1.16
Step-by-Step Solution & Explanation
The Relative Span Factor ($RSF$) is a dimensionless parameter describing the width (uniformity) of a spray droplet distribution:
$RSF = \frac{D_{90} - D_{10}}{D_{50}}$
Given $D_{90} = 410\text{ }\mu\text{m}$, $D_{10} = 120\text{ }\mu\text{m}$, and $D_{50} = 250\text{ }\mu\text{m}$:
$RSF = \frac{410 - 120}{250} = \frac{290}{250} = 1.16$