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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.


Volume and Wetted Area of Partially Filled Vertical Vessels
Volume and Wetted Area of Partially Filled Vertical Vessels

The calculation of the wetted area and volume of a vertical vessel is required for engineering tasks such fire studies and the determination of level alarms and control set points. However the calculation of these parameters is complicated by the geometry of the vessel, particularly the heads. This article details formulae for calculating the wetted area and volume of these vessels for various types of curved ends including: hemispherical, torispherical, semi-ellipsoidal and bumped ends.


Manning Characteristic Roughness
Manning Characteristic Roughness

The Manning Characteristic Roughness is used to characterise the surfaces over which water can flow in streams, channels, ditches and flumes. This article presents a reference of roughness values for many common materials of construction for channels and natural formations of streams.


Flow in Open Channels and Partially Filled Pipes
Flow in Open Channels and Partially Filled Pipes

The transport of fluid under gravity is often achieved using partially filled pipes, channels, flumes, ditches and streams. To determine the slope and elevation change required or the flow rate that is achievable one must be able to calculate the head loss and friction factor. This article provides relationships for the calculation of head loss and friction factor for fluids flowing via these conduits.


Mach Number

The Mach number is the ratio of the relative velocity of a fluid to the local speed of sound. This article provides the equation for the calculation of the Mach number and a discussion of its uses.


Speed of Sound in Fluids and Fluid in Pipes

This article provides the formulae for the calculation of speed of sound in fluids and fluid filled circular pipes. The speed of sounds is important in piping systems for the calculation of choked flow for gases and pressure transient analysis of liquid filled systems.


Bulk Modulus of Elasticity of Liquids

The bulk modulus or elasticity is a measure of the resistance to compression of a substance. This article presents the bulk modulus for various liquids.


Comparing Volumetric Flow Rates for Equivalent Pressure Loss

Standard volumetric flow rates of a fluid are often used to describe the capacity of a vent or pressure relief device. To determine how this capacity compares for another fluid under different pressure and temperature conditions a conversion must be made on the basis of equivalent pressure loss. This article describes the method for calculating the volumetric flow rate of a gas which will give the equivalent pressure drop to another gas through a fixed restriction such as a vent.


Torricelli's Law
Torricelli's Law

This article presents Torricelli’s law, a simplified method of estimating the velocity of fluid passing through an open orifice under static pressure.


Bernoulli's Equation
Bernoulli's Equation

Bernoulli’s Principle is an important observation in fluid dynamics which states that for an inviscid flow, an increase in the velocity of the fluid results in a simultaneous decrease in pressure or a decrease in the fluid’s potential energy. This principle is often represented mathematically in the many forms of Bernoulli’s equation. This article presents some useful forms of Bernoulli’s Equations and their simplifying assumptions.


Exponent Laws
Exponent Laws

Algebraic expressions can often be simplified and subsequently solved through the use of the exponent laws (also called laws of indices or power laws). These laws allow an equation to be manipulated into a form which provides enhanced readability or opens up potential simplifications and substitutions. This article provides a reference for these laws.


Algebraic Factoring
Algebraic Factoring

When developing algebraic expressions it is often useful to factorise the expression to familiar components. Through factorisation, one can increases both the readability and manipulability of the expression. This article summarises the common algebra factorisation relationships.


Laws of Thermodynamics

The laws of thermodynamics are fundamental laws which describe the behaviour of heat and work in a thermodynamic system. These laws forbid phenomena such as perpetual motion machines, a hypothetical machine the development of which was pursued during the industrial revolution.


Specific Energy and Energy Density of Fuels

Specific energy and energy density are useful measures of the energy that will be released from a given weight or volume of fuel when it is burned. This article provides a quick reference for common values of specific energy and energy density.


Pressure Loss in Hoses
Pressure Loss in Hoses

The Pressure loss through a hose is often approximated using coarse heuristics, but utilization of more accurate correlations increase the efficiency of pump and piping designs. This article presents more accurate methods to estimate the pressure loss in various type of hoses using multiples of the pipe length. Methods of estimating pressure loss caused by couplings, curves and coiled hose are also detailed.


Heat of Combustion

The heat of combustion is the energy liberated when a substance undergoes complete combustion, at constant pressure usually in an environment with excess Oxygen. The heat of combustion is utilised to quantify the performance of a fuel in a combustion system such as furnaces, power generation turbines and motors. This article describes the heat of combustion and provides a list of heats of combustion for commons fuels and fuel components.


Thermal Relief Cascades
Thermal Relief Cascades

For systems where liquid product may be trapped in a pipe section of an extended period of time thermal expansion can become a problem. Heating of the fluid in the pipe results in a rapid pressure rise as the fluid expands which can quickly exceed the design pressure of the pipeline. The damaging effects of the thermal expansion can be mitigated through the use of thermal relief valves and where there is several potential pipe blockages in series, it is often necessary to ‘cascade’ thermal relief valves back to a tank. This article describes how to design a cascading thermal relief system.


Baumé Scale

The Baumé scale was first developed in 1768 as a method of measuring the density of liquids. Today it is largely superseded, however it is still used in some industries as a measure of density or concentration. This article presents formula for the calculation of degrees Baumé for a liquid.


API Gravity

API gravity is measure of the density of liquid hydrocarbons relative to water. This article provides a reference to the API gravity calculation formula and some typical values of API gravity for common hydrocarbons.


Calculating Thermal Relief Flow Rates

For long sections of pipe, the thermal expansion of trapped liquid can be significant. It is often required that the increase in volume of the fluid be determined in order to select suitable thermal relief valves to protect the integrity of the pipework. This article details how to calculate the required relief flow rate to prevent over pressure due to thermal expansion.


Flash Steam
Flash Steam

When condensate is discharged from a high pressure steam system to a system of lower pressure, a proportion of the condensate may vaporise to form low pressure steam. This is known as flash steam and may be utilised in low pressure heating systems to improve plant efficiency. This article discusses the generation of flash steam and presents a method by which it can be quantified.


Calculating Interface Volumes for Multi-product Pipelines
Calculating Interface Volumes for Multi-product Pipelines

Due to their large capital expense, pipelines are often utilized for the transfer of multiple products. During operation of these multi-product pipelines, the interface between two adjacent products extends (referred to as interface mixing), resulting in the contamination of each product. This interface is typically sent to slops collection for reprocessing or disposal at additional cost to the operator. Therefore the economics of a pipeline can often be improved through a study of product interfaces under various operational conditions to aide in the minimization of interface mixing. This article presents several empirical methods by which interface mixing can be quantified.


Thermal Conductivity of Metals and Alloys

This article provides thermal conductivity data for a selection of metals and alloys. Thermal conductivity measures a materials ability to allow heat to pass through it via conductance.


Thermal Conductivity of Common Materials

This article provides thermal conductivity data for a selection of common materials. Thermal conductivity measures a materials ability to allow heat to pass through it via conductance.


Estimating the Viscosity of Mixtures

For some engineering calculations, particularly in hydrocarbon processing, it is necessary to estimate the viscosity of a mixture (blend) of two or more components. This article presents the Gambill and Refutas methods, which are commonly used in petroleum refining for predicting the viscosity of oil blends.


Relief Valve Orifice Area to API RP 526

This article lists the standard effective orifice areas for the orifice designations found in API RP 526 5th edition. These orifice designations set the minimum effective orifice area which a relief valve must have to meet the API 526 requirements and must be used with the sizing equations in API RP 520 Part I.