How to Design a Pump for Reduced NPSH

by Kerry Oliphant on Jun 20, 2017 4:39:30 PM

Cavitation occurs in a pump when the bulk liquid pressure starts to approach the vapor pressure of the liquid, and cavities of vapor form as seen in Figure 1.  This figure shows the inlet of a cavitating pump tested in Concepts NREC’s water flow loop.  These cavities can degrade the head rise and efficiency of the pump, create instabilities, and cause significant damage to the pump impeller and other components.  To avoid these effects, a pump must operate with an inlet head that is at least as high as the required net positive suction head (NSPH) that the pump was designed to achieve.  The NPSH is the difference in the inlet head and the liquid vapor head (or vapor pressure converted to liquid head).  Many pumping systems would benefit from the ability to operate at lower NPSH and so reducing the required NPSH of a pump is often of great concern to pump designers.

Turbomachinery is the Key for Sustainable Development

by Thiago Ebel on Jun 15, 2017 4:28:44 PM

While common sense might lead one to conclude otherwise, increasing energy consumption worldwide is a good thing. Higher per capita energy consumption is associated with a higher quality of life: electricity for home appliances, transportation, affordable heating, lighting and so on. On the other hand, there is and should be enormous concern about the type of energy being used to fuel this increased consumption stemming from issues such as environmental impact, national security, etc.  

The chiller industry is under tremendous pressure to convert to new, more environmentally friendly refrigerants.  This change is driven by new global regulations including, the Montreal Protocol and European Union (EU) F-gas regulation. Many chiller OEMs are already announcing new lines of chillers redesigned to use this latest generation of refrigerants. OEMs that have not have started their redesign efforts have a lot of work to do.

New engine development is a costly endeavor and making the right decisions early in the engine design is extremely important. It requires multi-disciplinary consideration of the engine thermodynamic cycle coupled with preliminary aerodynamic design of key engine components. This includes evaluation of size, weight and cost parameters, with constraints imposed by aero, structural, geometrical, manufacturing, and material requirements.

Multidisciplinary Optimization of Turbocharger Turbine with Non-Radial Blades for Two Operating Points

by Dr. Nicholas C. Baines and Oleg Dubitsky on May 25, 2017 6:02:28 PM

The turbine of an automotive turbocharger is subject to a wide and demanding range of requirements and constraints. High efficiency is required to reduce the pumping work of the engine that can make a small but desirable improvement in fuel economy. The automotive application also requires a good transient response, and a low rotating inertia of the turbine is necessary for this. Durability and the ability to operate for a guaranteed lifetime are required – but such performance is not easy to achieve, given the hot gas environment and the way the turbine is subject to frequent changes in condition. The market is very competitive, and so manufacturing cost is very important. These various factors are in competition with each other, and a successful turbine is one that achieves the right balance between them, rather than one that excels in one particular area.

A Cross-Over SCO2 System Application

by Francis A. Di Bella, P.E. on May 18, 2017 3:12:23 PM

The 2015 Paris Climate Talks (COP21) were successful in achieving consensus from 196 countries that climate change must be given significant attention. There was a particular focus on the release of carbon, in the form of carbon dioxide and carbon monoxide, as something that must be curtailed.

Using FINE™/Turbo for CFD Analysis in AxCent®

by Daryl L. Bonhaus on May 11, 2017 9:24:38 PM

In May of 2016, Concepts NREC and NUMECA International announced a strategic partnership to combine their products to provide a comprehensive turbomachinery design and analysis system. In November of 2016, Concepts NREC released version 8.5 of its Agile Engineering Design System, the first version to integrate NUMECA's FINE/Turbo product for CFD analysis. Geometry and boundary-condition data specified in AxCent are automatically passed to FINE/Turbo to set up the CFD calculation. Many of the FINE/Turbo grid generation parameters and solver settings are provided in the AxCent interface to allow a CFD calculation to be set up and run without leaving the AxCent application.

Advantages of an Integrated, Turbomachinery Specific FEA  System

by John Keeling on May 3, 2017 1:01:37 PM

The biggest reason to use an integrated turbomachinery design and analysis environment is speed. Basically, having everything you need in one place makes a big difference!

Improving the Efficiency of Supercritical CO2 Power Systems

by Francis A. Di Bella, P.E. on Apr 27, 2017 8:35:39 AM

The contemporary gas turbine engine, developed in the 1940’s by Sir Frank Whittle (pictured), is still considered to be among the most efficient, external combustion engines. Today, there is a resurgent interest in power generation technology driven by humankind’s insatiable need for more power. A popular focus is to extend the Brayton Cycle, the thermodynamic basis for a gas turbine engine, to using CO2 in a closed Brayton Cycle. This is commonly referred to as a Supercritical CO2 (sCO2) system. As the name implies, the CO2 is at pressures above the critical point of CO2 or 1,070 psia. The highest pressure in the cycle can often be designed to be 4 times this pressure and operate at temperatures as high as 700°C at the inlet to the turbine. 

Turbocharger Market – Is There Room for Growth?

by Dr. Nicholas C. Baines on Apr 20, 2017 1:19:51 PM

The recent announcement that Bosch Mahle Turbosystems is up for sale demonstrates just how difficult it is to succeed in the mainstream turbo market that is already served by very well established OEMs. It’s hard to see that they did anything wrong. They were funded by two very large companies, they had a very large lead customer, a realistic timescale to profitability, and an early presence in China.

Topics: Turbochargers
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