Charles Parsons and His Contribution to Engineering

Welcome to this special edition of the SoftInWay blog! While we at SoftInWay are known for helpful articles about designing various machines, retrofitting, and rotordynamics, we believe it is also important to examine the lives of some of the men and women behind these great machines.

The compound steam turbine is one of the greatest inventions, not just in turbomachinery but around the world. Once it was introduced to the marine industry, the steam turbine exploded in popularity as a means of allowing ships to travel faster and farther than ever before. It would go on to become a critical part in the naval arms race that preceded the First World War. The steam turbine not only revolutionized marine and naval propulsion, it became one of the best ways to generate electricity. After its inception, the steam turbine became one of the best ways to reliably generate power on a large scale, and make electricity the regular utility that it is today. But who invented the modern steam turbine?

Sir Charles Parsons
Image courtesy of Wikimedia

Sir Charles Algernon Parsons, (1854 – 1931), is the inventor of the modern steam turbine. The work he undertook in his life had a massive impact on the world, continuing the legacy of James Watt by bringing steam technology into the modern era. Born on June 13th 1854 into an Anglo-Irish family, Sir Charles Parsons was born into a well-respected family with roots in County Offaly, Ireland. In fact the town now known as Birr was then known as Parsonstown, from the early 1600’s through to 1899. Parsons was the sixth son of the 3rd Earl of Rosse, and had a family lineage that had made great strides in the areas of military, political, and physical science. The family’s castle in Birr, which is still owned by the Parsons family and is the permanent residence of the 7th Earl of Rosse, was a rendezvous for men of science during the childhood of Sir Charles. Suffice it to say, there was no better place for a future-engineer to grow up. He alongside his brothers would receive private tutorship from Sir Robert Ball and Dr Johnstone Stoney, famous Irish astronomer and physicist, respectively. Read More

Basics of Steam Turbine Design

Steam turbines account for more than half of the world’s electricity production in power plants around the world and will continue to be the dominant force in electricity power generation for the foreseeable future. The enhancement of steam turbine efficiency is increasingly important as the urgency to reduce CO2 emissions into the atmosphere is a problem at the forefront of power production. Increasing efficiency in steam turbines, and other components of power plants, will help meet the growing demands for electricity worldwide while reducing harmful greenhouse emissions.

Figure 1 Steam Turbine with Long Last-Stage Blades
Figure 1. Steam Turbine with Long Last-Stage Blades. Source

Steam turbines are used in coal-fired, nuclear, geothermal, natural gas-fired, and solar thermal power plants. Also steam turbines are increasingly needed to stabilize fluctuating power demands from solar and wind power stations as renewable energy sources grow worldwide. The current emphasis on steam turbine development is for increasing efficiency, mainly by increasing steam turbine capacity, as well as increasing operational availability, which translates to rapid start up and shut down procedures.  Read More

Choosing the Right Turbomachinery Component

Traditionally the engineering process starts with Front End Engineering Design (FEED) which is essentially the conceptual design to realize the feasibility of the project and to get an estimate of the investments required. This step is also a precursor to defining the scope for Engineering Procurement and Construction Activities (EPC). Choosing the right EPC consultant is crucial as this shapes the final selection of the equipment in the plant including turbomachinery.

Large thermal power machine

Choosing the right component for the right application is not an easy task. Too many times, one ends up choosing a component that is not the best choice by far. This is quite true when we look at component selections in the process industries compared to those in a power plant where the operating conditions are more or less constant. This improper selection of components is due to multiple reasons such as: insufficient research and studies; limitation of time, resources, budget etc. Read More

Unsteady Flow Simulation in Hydraulic Systems

[:en]An unsteady flow is one where the parameters change with respect to time. In general, any liquid flow is unsteady. But if a hydraulic system is working at constant boundary conditions, then the parameters of the fluid flow change slowly; thus this flow is considered steady. At the same time, if the parameters of the fluid flow oscillate over time relative to some constant value, then it called quasi-steady flow 1.

In practice, most fluid flows are steady or quasi-steady. Examples of the three flows are presented in Figure 1. Steady flow is presented by a simple pipe. The quasi-steady flow is represented by a sharpened edge channel. The unsteady flow is presented by an outflow from a reservoir.

Figure 1 - Different Types of Fluid Flow
Figure 1 – Different Types of Fluid Flow
Different Cases of Unsteady Flow

During operations, hydraulic systems act for long intervals at steady conditions which are called operating modes. Change between two different operating modes occurs over a short time interval (called a transient mode). If any hydraulic system works more than 95% of the time at these operating modes though, why is the unsteady flow is so important? Because the loads depend on time intervals. If the load is less, then the maximum system pressure is higher. Read More

Gas Turbine Lubrication Systems

Gas turbines have had a presence in many industries for more than a century. They are a unique technology for either producing an energy or propelling a vehicle and the efficiency of modern gas turbines is being improved continuously. One of them, a cooling system, has been described in earlier blogs. Another is the lubrication system of a gas turbine which we will cover in this blog. This  system, similar to that of a piston engine or a steam turbine, provides lubrication to decrease mechanical losses and prevent of wear on friction surfaces. Another function is the removal of heat released during friction by high rotational part and transmitted from the hot part of a turbine.  The basic units which need lubrication are the bearings supporting a shaft of a gas turbine 2.

Modern Dual Journal
Figure 1. The construction of modern dual journal4
Elements for lubrication

In a common case, gas turbine installation contains three main journal bearings used to support the gas turbine rotor 3. Additionally, thrust bearings are also maintained at the rotor-to-stator axial position 4. Click here for additional information about optimization of journal bearings. The bearing has important elements in its construction to prevent leakages from a lubrication system. The work, design and analysis of labyrinth seals is describe here.

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Optimization of the Closed Supercritical CO2 Brayton Cycle with the Detailed Simulation of Heat Exchangers

Recently scientists and engineers have turned their attention again to carbon dioxide as a working fluid to increase the efficiency of the Brayton cycle. But why has this become such a focus all of a sudden?

The first reason is the economical benefit. The higher the efficiency of the cycle is, the less fuel must be burned to obtain the same power generation. Additionally, the smaller the amount of fuel burned, the fewer emission. Therefore, the increase in efficiency also positively affects the environmental situation. Also, by lowering the temperature of the discharged gases, it is possible to install additional equipment to clean exhaust gases further reducing pollution.

So how does all of this come together? Figure 1 demonstrates a Supercritical CO2 power cycle with heating by flue gases modeled in AxCYCLE™. This installation is designed to utilize waste heat after some kind of technological process. The thermal potential of the exhaust gases is quite high (temperature 800° C). Therefore, at the exit from the technological installation, a Supercritical CO2 cycle was added to generate electrical energy. It should be noted: if the thermal potential of waste gases is much lower, HRSG can be used. More information on HRSG here:

Any cycle of a power turbine installation should consist of at least 4 elements : 2 elements for changing the pressure of the working fluid (turbine and compressor) and 2 elements for changing the temperature of the body (heater and cooler). The cycle demonstrated in Figure 1 has an additional regenerator, which makes it possible to use a part of the heat of the stream after the turbine (which should be removed in the cooler) to heat the stream after the compressor. Thus, part of the heat is returned to the cycle. This increases the efficiency of the cycle, but it requires the introduction of an additional heat exchanger.

The heat exchangers used in the sCO2 cycle are of three basic types: heaters, recuperators, and coolers. Typical closed Brayton cycles using sCO2 as the working fluid require a high degree of heat recuperation.

Supercritical CO2 Power Cycle with Heating by Flue Gases
Figure 1 – Supercritical CO2 Power Cycle with Heating by Flue Gases

Having examined this scheme and examined the process in detail, we can draw the following conclusions about the advantages of this cycle which is demonstrated in Figure 2: Read More

Considerations when Designing Turbomachinery with sCO2 as a Working Fluid

Supercritical CO2 (sCO2) power cycles offer higher efficiency for power generation than conventional steam Rankine cycles and gas Brayton cycles over a wide range of applications, including waste heat recovery, concentrated solar power, nuclear, and fossil energy. sCO2 cycles operate at high pressures throughout the cycle, resulting in a working fluid with a higher density, which will lead to smaller equipment sizes, smaller carbon footprint, and therefore lower cost. However, the combinations of pressure, temperature, and density in sCO2 power cycles are outside the experience of many designers. Challenges in designing sCO2 cycles include turbomachinery aerodynamic and structural design, bearings, seals, thermal management and rotordynamics. According to the report from Sandia National Lab, compressors operating near critical point and turbines have received only TRL (technical readiness level) 4 and 5 out of 9. This blog discusses the impact on turbomachinery design.

Radial or Axial

The selection of radial or axial for turbomachinery is typically performed based on the operating conditions (adiabatic head H and inlet volumetric flow Q). Non-dimensional turbomachinery parameters of specific speed Ns and specific diameter Ds can be selected from NsDs charts to estimate size, speed, and type of turbomachinery. Turbomachinery types for a sCO2 recompression cycle with scales ranging from 100 kW to over 300 MW have been studied and concluded that systems below 10 MW will likely feature only radial turbines and compressors with a single-stage or low stage counts. Such recompression cycle can be simulated in AxCYCLE™ tool which is shown in Figure 1. As size increases, the most efficient configuration for the turbine and recompressor transitions from radial to axial at approximately 30 MW and 100 MW, respectively. Suitable types of turbomachinery and its components for different power range can be reviewed in Figure 2. A radial configuration for the main compressor was expected at all scales due to its lower volume flow and wider range to facilitate variation in gas properties due to operation near the critical point.

Recompression Cycle simulated in AxCYCLE
Figure 1 – Recompression Cycle Simulated in AxCYCLE

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Introduction to Heat Recovery Steam Generated (HRSG) Technology

[:en]The acronym HRSG (Heat Recovery Steam Generated) is in different sources describing the operation of cogeneration and heating plants, but what does it mean? Heat Recovery Steam Generated (HRSG) technology is a recycling steam generator which uses the heat of exhaust from a gas turbine to generate steam for a steam turbine generating electricity.

The simplest scheme of a Combined Cycle Gas Turbine (CCGT) is presented in Figure 1.

The simplest scheme of CCGT
Figure 1: The simplest scheme of CCGT.

In Figure 1, the exhaust flue gases temperature on the outlet of the turbine is equal to 551.709 ℃. This is a too high a temperature to release the gasses into the environment. The excess heat is able to be disposed of while receiving additional electric power which is approximately equivalent to 30% of the capacity of a gas turbine.

To reach the maximum economical and eco-friendly criteria possible for the installation, many pieces of equipment are used including: a waste heat boiler (HRSG); turbines with a selection for a deaerator (Turbine With Extraction, Deaerator); feed and condensate pumps (PUMP2, PUMP); a condenser (Condenser); and a generator (Generator 2). Exhaust gases entering into the HRSG transfer heat to water which is supplied by the condensate pump from the steam turbine condenser to the deaerator and further by the feed pump to the HRSG. Here boiling of water and overheating of the steam occurs. Moving further, the steam enters the turbine where it performs useful work.

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Oil Systems for Turbine Lubrication

[:en]The oil system is an integral element of the turbine unit, which largely determines its reliability and trouble-free operation. The main purpose of the turbine lubricating oil system is to provide fluid friction in the bearings of turbines, generators, feed pumps, and gearboxes.

An oil system should provide:

– continuous supply of the required amount of oil in all modes of operation of the turbine unit, which guarantees:

  • – prevention of wear on friction surfaces;
  • – reduction of friction power losses;
  • – removal of heat released during friction and transmitted from the hot parts of the turbine

– maintaining the required temperature of the oil in the system; and

– cleaning the oil from contamination.

At the same time, the necessary qualities of the lubricating oil system are reliability, safety of operation, ease of maintenance.

The pressure and the temperature of the oil should be constantly monitored during operation of the turbine unit. Specifically, the lube oil temperature after the bearings requires special attention. Overheating of the bearing leads to wear of the working parts and changes in the properties of the lubricant itself. The quality of the lube oil is controlled by physicochemical characteristics such as density and viscosity. The system leaks must be stopped quickly and oil replenished on time. These factors will significantly extend the service life of the steam turbine.

Nowadays, computer simulation is a very powerful and useful tool. It helps you predict the processes occurring in the bearing chambers, and determine the flow of the working fluid when the operating modes change, all without installing expensive experimental equipment.

We suggest using the 1D-Analysis AxSTREAM NET™ tool to simulate the lubrication system. This software product allows you to quite simply, clearly and quickly build the desired model. It provides a flexible method to represent fluid path as a set of 1D elements, which easily can be connected to each other to form a thermal-fluid network. The program calculates fluid flow parameters for inlet and outlet of each element. There are many different components that allow you to simulate stationary and non-stationary modes. Also there is a convenient library of fluids. It is also possible for a user to add fluids of their choice.

The example of modeling in AxSTREAM NET™ is the system of oil supply for the K-500-240 turbine. This turbine is quite massive with bearing loads of up to 450 kN. The schematic diagram of the oil supply K-500-240-2 is shown in Figure 1.

Figure 1 Principle Scheme of K-500-240 Steam Turbine
Figure 1. Principle Scheme of K-500-240 Steam Turbine.


(1 – main tank; 2 & 3 – pumps; 4 – oil cooler; 5 – damp tank; 6 – journal bearings; 7 – thrust bearing).

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An Overview of Axial Fans

[:en]Axial fans have become indispensable in everyday applications starting from ceiling fans to industrial applications and aerospace fans.  The fan has become a part of every application where ventilation and cooling is required, like in a condenser, radiator, electronics etc., and they are available in the wide range of sizes from few millimeters to several meters. Fans generate pressure to move air/gases against the resistance caused by ducts, dampers, or other components in a fan system. Axial-flow fans are better suited for low-resistance, high-flow applications and can have widely varied operating characteristics depending on blade width and shape, number of blades, and tip speed.

Fan Types

The major types of axial flow fans are: propeller, tube axial, and vane axial.

  • – Propellers usually run at low speeds and handle large volumes of gas at low pressure. Often used as exhaust fans these have an efficiency of around 50% or less.
  • – Tube-axial fans turn faster than propeller fans, enabling operation under high-pressures 2500 – 4000 Pa with an efficiency of up to 65%.
  • – Vane-axial fans have guide vanes that improve the efficiency and operate at pressures up to 5000 Pa. Efficiency is up to 85%.
Types of Fans
Figure 1 Different Types of Axial Fans
Aerodynamic Design of an Axial Fan

The aerodynamic design of an axial fan depends on its applications. For example, axial fans for industrial cooling applications operate at low speeds and require simple profile shapes. When it comes to aircraft applications however, the fan must operate at very high speeds, and the aerodynamic design requirements become significantly different from more traditional fan designs. Read More