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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.


Types of Thermodynamic Process

When examining thermodynamic processes some simplifying assumptions may be applied to help describe and analyse a given system. These simplifications can be viewed as 'ideal' thermodynamic processes and include adiabatic, isenthalpic, isentropic, isobaric, isochoric, isothermal, isentropic, polytropic and reversible processes. This article provides a brief overview of each process type and suitability to a given thermodynamic system.


Hydrate Formation in Gas Systems
Hydrate Formation in Gas Systems

Hydrate formation represents a significant risk to process safety as it can result in the plugging of both pipes and instruments. Hydrates typically form in process where light hydrocarbons, water vapor and low temperatures or high pressures are present. This article describes the conditions under which hydrates form, how formation may be prevented and what can be done once hydrates have formed.


Choked Flow
Choked Flow

Choked flow is a phenomenon that limits the mass flow rate of a compressible fluid flowing through nozzles, orifices and sudden expansions. Generally speaking it is the mass flux after which a further reduction in downstream pressure will not result in an increase in mass flow rate.


Erosion Velocity for Gas-Liquid Multiphase Flow
Erosion Velocity for Gas-Liquid Multiphase Flow

The flow of a gas-liquid multiphase system may cause erosion if velocities are high. This article presents an empirical relationship for estimating whether erosion will occur in a system at a certain velocity.


Discharge Coefficient for Nozzles and Orifices
Discharge Coefficient for Nozzles and Orifices

The discharge coefficient is a dimensionless number used to characterise the flow and pressure loss behaviour of nozzles and orifices in fluid systems. Orifices and nozzles are typically used to deliberately reduce pressure, restrict flow or to measure flow rate. This article gives typical values of the discharge coefficient for common orifice and nozzle designs.


Calculation of Flow through Nozzles and Orifices
Calculation of Flow through Nozzles and Orifices

This article provides calculation methods for correlating design, flow rate and pressure loss as a fluid passes through a nozzle or orifice. Nozzles and orifices are often used to deliberately reduce pressure, restrict flow or to measure flow rate.


Fitting of a Polynomial using Least Squares Method
Fitting of a Polynomial using Least Squares Method

Approximating a dataset using a polynomial equation is useful when conducting engineering calculations as it allows results to be quickly updated when inputs change without the need for manual lookup of the dataset. The most common method to generate a polynomial equation from a given data set is the least squares method. This article demonstrates how to generate a polynomial curve fit using the least squares method.


Joukowsky Equation

The Joukowsky equation is a method of determining the surge pressures that will be experienced in a fluid piping system. When a fluid in motion is forced to either stop or change direction suddenly a pressure wave will be generated and propagated through the fluid. This pressure wave is commonly referred to as fluid hammer (also known as water hammer, surge or hydraulic shock) and typically occurs in piping systems when a valve is suddenly closed, isolating the line. The resultant surge pressures are complex to characterise but for simple systems they may be calculated using the Joukowsky equation.


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.


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.