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.
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
The following is an excerpt from Exceptional People Magazine, conducted by Monica Davis and focused on profiling SoftInWay’s CEO, Dr. Leonid Moroz. The article appeared in the September/October 2019 issue. A link to the full interview can be found here
Turbomachinery design is critical in industries like aerospace, oil and gas, defense, and clean technology. Dr. Leonid Moroz’s company, SoftInWay Inc., also helps some of the world’s largest manufacturers of turbines, turbochargers, pumps, and fans. But Moroz is happy to explain that his company’s innovations also impact the car you drive, the vacuum cleaner you use, the air conditioning in which you work, and the electricity needed to power your mobile phone.
A lover of music and athletics as a child, Moroz knew early on that engineering held promise as a lifelong career. So he started his career as a Group Leader at TurboAtom. TurboAtom, while a state-owned entity, is one of the world’s top thermal, nuclear, and hydropower plant turbine construction companies. It’s a company that operates at the level of companies like General Electric and Siemens.
Moroz designed both gas and steam turbines during his eight years at TurboAtom. While he was there, he also earned his Ph.D. in Turbomachinery from the Kharkiv Polytechnic Institute in Ukraine.
When he founded global aerospace engineering leader SoftInWay, Inc. in 1999, he intended to assist turbomachinery manufacturers needing his expertise. What evolved from that intent has revolutionized engineering design and allowed improved efficiencies for multiple system types: Its flagship software, AxSTREAM.
AxSTREAM helps engineers develop efficient turbomachinery flow path design, redesign, analysis, and optimization. Under Moroz’ direction, AxSTREAM itself has also evolved into a design platform supporting rapid development of a new generation of liquid rocket engines.
Still a relatively small company, SoftInWay supports over 400 companies worldwide and works closely with universities, research laboratories, and government organizations. The company takes its educational responsibilities seriously, continually offering webinars, training sessions, educational blogs, and online workshops on topics like When To Upgrade Your Pump, The Pros and Cons of Wind Energy, and Radial Outflow Turbine Design.
Moroz loves to talk about his work, his company, its innovations, and his team. He’s proud to have had the same group of engineers for 30 years, so SoftInWay feels more like a family than a workplace. As the company has become a leading global R&D engineering company, it has expanded to encompass locations in Boston, Massachusetts; Zug, Switzerland; Ukraine; and India.
Yes, Moroz’ specialty is indeed a bit technical for people who aren’t in turbomachinery engineering design. But Moroz and his team clearly enjoy what they’re doing because it benefits society and makes life easier and more comfortable in myriad ways.
Next time you switch on that ShopVac or Hoover, be sure to thank Dr. Leonid Moroz.
Monica: We often take for granted how engineering plays a huge role in our daily lives. How much of the world depends on the kind of technology and engineering capabilities you produce?
Dr. Moroz: Quite substantially. For example, society produces a lot of waste and heat. If you have options, it utilizes waste and heat to produce power, or it is thrown away. We’ve helped companies to utilize this energy and to produce power to heat or cool our houses, to prepare food, and to help our businesses survive.
Another example again would be launchers design. Launchers are important for turbomachinery. A significant part of space development depends on turbomachinery inside those launchers.
It’s important to understand two directions where people can utilize turbomachinery with power consumption and power generation. Power generation is when you produce power, so we need to be more efficient, but the second part, when we get this power, we need to cool our houses, we need to cool our cars, and so on, and again, it’s turbomachinery.
You can be sure that you utilize turbomachinery to develop an air conditioning system that is efficient and is quite substantially in large buildings.
Power consumption for air conditioning is like 30 or 40 percent of the overall power consumption. Can you imagine if you were to decrease this by 10 to 20 percent? It would be a considerable saving…Read the full interview here
In every modern cleaning system there exists at least one pumping unit. With this in mind, understanding how it works and how to use it efficiently is critical to the successful operation and maintenance of that cleaning system. This blog will discuss centrifugal pumps in this context and take a look at important attributes to bear in mind when working with these systems.
In general, pumps are devices which impart energy to a flow of liquid. Although there are different types of pumps based on the flow direction, blade designs, and so on, centrifugal pumps are in the majority of those used in cleaning systems. Centrifugal pumps are simple, efficient, reliable, relatively inexpensive, and easily meet the needs of most cleaning system requirements including spraying, overflow sparging, filtration, turbulation and the basic function of moving liquids from one place to another using pressure.
A centrifugal pump uses a combination of angular velocity and centrifugal force to pump liquids. The below figure illustrates the working principle of the centrifugal pump.
The pump consists of a circular pump housing which is usually made up of metals, (stain steels etc.) solid plastic, or ceramics. The outlet extends tangentially from the diameter of the pump housing. Inside the pump housing there is a rotating component an “impeller” which rotates perpendicular to the central axis and is driven by a shaft secured to its center of rotation. The shaft, powered by an electric motor, enters the pump housing through a liquid tight seal which prevents leaking. Liquid entering the pump through the inlet is swirled in a circular motion and displaced from the rotation center of the impeller by centrifugal force. The combination of the swirling action (angular velocity) and centrifugal force (radial velocity) pushes the liquid out of the pump through the outlet.
Axial and mixed flow fans have been in high demand for a number of years. The application of these machines span many different industries including HVAC, automotive, appliance, military equipment, and much more. Like many other types of turbomachinery, changing industry standards and market trends have resulted in fierce rivalry to compete on lifespan, efficiency, environmental and user friendliness, and overall quality. With this in mind, it goes without saying that companies are looking for tools needed to develop highly efficient equipment while minimizing noise as quiet fans are typically more desirable which results in higher demand and marketability.