# Welcome to Neutrium

Neutrium is a knowledge base of engineering topics, centred mainly around chemical engineering design challenges faced by engineers in their daily work. We created Neutrium to bridge the gap between theory and practice. Feel free to ask a question, leave feedback or take a look at one of our in-depth articles.

This article describes the method of calculating the velocity head of flowing fluid. The velocity head uses units of length as a measure of the kinetic energy of the flowing fluid.

This article presents the method to convert between pressure and head for several common unit sets. Head relates the pressure of a fluid to the height of a column of that fluid which would produce an equivalent static pressure at its base. It is particularly useful for the specification of pumps as it provides a measure of pressure as it is independent of fluid density.

Affine transformations are a class of transformations fundamental to modelling objects in three dimensions. This article presents the transformation and inverse transformation matrices for translating, scaling and rotating.

When working on problems in three dimensional space it is often required convert between two or more co-ordinate systems. This article presents the formulae to convert between Cartesian and Spherical co-ordinate systems.

There are several common ways to express the losses caused by pipe fittings and equipment. Depending on the calculation programs or methods available and engineer may require to convert between one form or another. This article details the equations required to convert between the resistance coefficient and flow coefficient methods (K, Cv and Kv).

This article contains formulae and tabulated data for the properties of air as a function of temperature.

Restriction orifices and control valves are commonly used for pressure reduction and measurement of flow rates, however for a liquid system, excessive pressure drop across these items of equipment may result in cavitation. This article describes methods of predicting cavitation across restriction orifices and valves and proposes designs which may be used to avoid cavitation.

This article details the most common methods to quantify the concentration of a component in a mixture, and details how to convert between these concentrations. Concentration is commonly expressed in moles per volume, mass per volume, mass percentage, volume percentage, mole percentage and parts per million. Using density and/or molecular weight properties it is possible to convert between any of the above measures.

Viscosity is a measure of a fluids propensity to flow. There are two kinds of viscosity commonly reported, kinematic and dynamic. Dynamic viscosity is the relationship between the shear stress and the shear rate in a fluid. The Kinematic viscosity is the relationship between viscous and inertial forces in a fluid. Most common fluids are Newtonian fluids and their viscosity is constant with shear stress and shear rate. Non-Newtonian fluids are less common.

Fittings such as elbows, tees, valves and reducers represent a significant component of the pressure loss in most pipe systems. This article discusses the differences between several popular methods for determining the pressure loss through fittings. The methods discussed for fittings are: the equivalent length method, the K method (velocity head method or resistance coefficient method), the two-K method and the three-K method. In this article we also discuss method for calculating pressure loss through pipe size changes as well as control valves.