Dynamic solutions for a fluid world™


AFT to Present at Prestigious Pressure Surges Conference

Applied Flow Technology will present AFT Impulse Technical Papers at the 2018 Pressure Surges Conference in Bordeaux, France


COLORADO SPRINGS, Colo., USA, October 12, 2018 -- Applied Flow Technology's (AFT) very own Trey Walters, P.E. and Purple Mountain Technical Group's (PMTG), Dylan Witte, will join approximately one-hundred of the world's leaders in Bordeaux, France this November for the 2018 Pressure Surges Conference

According to the BHR Group, The Pressure Surges conference series has been running since 1972, with forerunners in 1971 and 1970. It is the leading conference in the world which aims to bring together practical engineers and theoretical academics, young and old, inexperienced and specialist, from all over the world. It provides updates on the latest developments in modeling, simulating and validating pressure surges and focuses on the topics of Big Transient Data and Small Smart Sensors. 

The 13th conference will embrace both traditional and novel subjects. Industrial papers will present case studies, each telling its own story. Research papers will give updates on the latest developments in modeling, simulating and validating pressure surges. Dedicated Forum papers will stimulate audience interaction with presenters and will complement other discussion and debate sessions dedicated to interactive participation.

The five papers AFT and PMTG will present showcase AFT's partnerships with world-renowned companies as well as a specialized software analysis tool used by these companies called AFT Impulse™. 

Over 20 years ago when Applied Flow Technology created AFT Impulse ™, they knew it would be a leader in the tools researchers and industries around the world would use to provide advanced solutions and solve waterhammer / surge issues. AFT Impulse brings confidence to the table. It has been matched against several other pieces of software and methods. Time and time again it provides reliable analysis data and helps engineers troubleshoot events and proactively build safe piping systems.

In addition to being used and trusted by thousands of engineers who specialize in transient events, the majority of AFT products are validated and verified for nuclear engineering use. Because of this verification and validation, AFT Impulse has been utilized in nuclear plants around the world. 

Applied Flow Technology will present four papers and Purple Mountain Technical Group will present one paper. Papers include: 


Making the world a safer and better place – a plea for more data, validation cases and guidelines for waterhammer simulation

T W Walters, Applied Flow Technology, USA | G G Orieux, Q Li, L Thomson, Enbridge Pipelines Inc, Canada

Engineers tend to overdesign systems when uncertainty exists. Overdesign is an important part of the engineering process, but unnecessary overdesign will only increase the cost of systems without enhancing safety. An experience between a major pipeline company,  their engineering design firm, and the waterhammer simulation software products used by both is described. A disagreement between software package results and ultimately the two companies developed into an issue that could significantly increase costs. More and better validation cases would have helped everyone navigate this situation more quickly, easily and inexpensively. More and better application guidelines may have helped the engineering design firm achieve higher certainty in their recommendations with potentially less overdesign.


Unappreciated challenges in applying four quadrant pump data to waterhammer simulation

T W Walters, S A Lang, D O Miller, Applied Flow Technology, USA

Part 1: Fundamentals
The transient analysis of reverse flow and rotation in pumps has evolved over the years into modern four quadrant pump waterhammer simulation. Exact characteristics for a given pump for reverse flow and/or reverse rotation are normally unavailable, and manufacturer curves are often mapped to previously published four quadrant data sets for similar pumps. Assumptions made in this mapping process can cause extreme differences in the simulation. If these assumptions are unaddressed, critically incorrect conclusions about the system’s transient behavior may be made, impacting both design and operation.
The available choices to the waterhammer analyst and the consequences of those choices are thoroughly detailed in Part 1 of this paper.

Part 2: Application Examples
Transient analysis of reverse flow and rotation in pumps requires the use of four quadrant data. This data is normally unavailable for a given pump, and existing dimensionless four quadrant data is selected based on specific speed. There are different methods for dimensionalizing the four quadrant data, which can result in significant differences in transient predictions. This study examines four examples with three exhibiting reverse flow. The two most convenient methods of dimensionalizing four quadrant data are used, and significant differences in transient predictions are demonstrated and discussed.


Surge transients due to check valve closure in a municipal water pumping station

D Lozano Solé 1, R Bosch Segarra 1, and T W Walters 2  | (1) Aquatec Proyectos para el Sector del Agua SAU (SUEZ Group), Spain  | (2) Applied Flow Technology, USA

The present study highlights the importance of proper check valve selection to mitigate waterhammer and its associated problems. Two different check valves were installed in a pumping station in a municipal water transfer system: a swing check valve and a nozzle check valve. Measurements were taken of pipeline pressures after a pump trip and resulting check valve closure. The field data was compared to predictions from a model using a commercial waterhammer tool. Commonly accepted methods for estimating reverse liquid velocity at check valve closure were utilized. Results were also compared to previous experimental test from other authors. The calibrated model results matched the field data quite well. Comparisons of inferred valve characteristics to previously published results for swing and nozzle valves were not in close agreement for either tested valve.


Surge mitigation in a marine fuel oil terminal

D Witte 1; D Jackson 2; T W Walters 3  | (1) Purple Mountain Technology Group, USA | (2) Sealaska, USA | (3) Applied Flow Technology, USA

Surge modeling of complex systems such as marine fuel oil terminals requires the use of accurate computer modeling techniques to help insure the best possible response to surge events. Various surge mitigation techniques can be pursued that often require information that manufactures rarely provide and have behavior that is problematic to replicate in a computer model. This paper provides guidance with one such device, the surge relief valve, and offers a case study in how they were used in conjunction with valve stroking to mitigate significant surge events at a terminal in the gulf coast region of the United States.


Print the Pressure Surges Papers Abstract Summary 




AFT Will Be in the Flow at the 2018 Turbomachinery & Pump Symposia

TPS Logo

Colorado Springs, CO, USA - Applied Flow Technology (AFT) will be at the 2018 Turbomachinery and Pump Symposia being held in Houston, Texas on September 18 - 20, 2018. 

Applied Flow Technology has had a presence at the international show for many years and is excited to return again in 2018. During the show they will have information about their flagship products:

  • AFT Fathom: used to calculate pressure drop and flow distribution in liquid and low velocity gas piping and ducting systems
  • AFT Arrow: used to calculate pressure drop and flow distribution in gas piping and ducting systems
  • AFT Impulse:  used to calculate pressure surge transients in liquid piping systems caused by waterhammer

AFT's Reinaldo Pinto and Scott Lang will also be on hand in booth 1335 to educate attendees about AFT's newest product: the Pulsation Frequency Analysis (PFA) Add-on Module which extends the already powerful capabilities of AFT Impulse so engineers can more readily analyze and model pulsation in piping systems. Engineers around the world can use PFA if their system has pulsation issues. Pulsation is a common problem in systems if the frequencies it excites are at or near the system’s acoustic resonant frequencies - often leading to system weakening and frequent maintenance outages.

The PFA add-on module automates most of the pulsation analysis process using a series of steps. Engineers can use the module to avoid system weakening, damage and/or failure; Reduce operating and maintenance costs; Minimize disruptions in production processes; Understand and predict resonant frequencies; Create scenarios to evaluate how large pressure pulsations are when operating at the resonant frequencies; and Compare the pressure pulsation magnitudes to API Standard 674 to check compliance.

To learn more about the TPS show: click here

AFT's President Teaching Short Course at Turbomachinery and Pump Symposia

Presented by: AFT President Trey Walters, P.E. and Peter Gaydon, Director of Technical Affairs, Hydraulic Institute

Topic:  "Optimizing Pumping Systems with Proven Engineering Assessment Processes and Methodologies"  

Date / Time / Location: Monday, September 18 from 8:30 a.m. - 5:00 p.m. in room 372c

Short Course Description: When pump systems are not optimized for best efficiency, they drain corporate profits with higher energy and maintenance costs, shorten mean time between repairs and increase CO2 emissions. Optimized pump systems are more energy efficient and reliable overall. Using information gained from this course, pump users can learn how to run their systems more efficiently and conduct a pump system assessment that identifies problematic areas where the greatest opportunities for improvement exist. This course/workshop can benefit companies in various industries including: wastewater, power generation, oil & gas, building services, steel, chemical processing, pulp & paper, food & beverage as well as mining.

Click here for more information about this and other short courses.

Welcome Rafael Hoyer

COLORADO SPRINGS, Colo., USA, September 4, 2018 - Applied Flow Technology would like to welcome Rafael Hoyer to our team of experts. Rafael will serve as an Applications Engineer with AFT’s Technical Support team as well as support AFT’s consulting service, Purple Mountain Technology Group.

Rafael comes to AFT from Caracas, Venezuela where he earned degrees in Mechanical Engineering (B.S.) from Central University of Venezuela; M.Eng. Project Management from Andres Bello Catholic University; and M.Eng. Designing of Piping Systems from Central University of Venezuela.

In his previous experience, Rafael served as a Project Engineer and an Operational Engineer. During his career, Rafael utilized AFT software to design fire protection systems, HVAC, and piping systems for refineries, and industrial complexes; as well as maintenance, inspection and mitigation planning of fixed equipment, such as atmospheric storage tanks, heat exchangers, boilers, pipes, etc… based on API, ASTM, ASME, AWS international standards.

Additionally, he was an Assistant Professor at Andres Bello Catholic University where he helped students develop an understanding of the principles related to thermodynamic laws as they pertain to properties, systems and thermodynamic processes.

Applied Flow Technology is proud to welcome Rafael, his wife (Alexandra) and his two children to the AFT family.

AFT Donates Software to Bright Engineering Minds at the University of Delaware

COLORADO SPRINGS, Colo., USA, August 8, 2018 --  Engineering students at the University of Delaware's Department of Electrical and Computer Engineering have a vision and they used the power of AFT Fathom to investigate. 

In April 2018, Applied Flow Technology (AFT) donated AFT Fathom to Josh Dubey and Keith Goossen to investigate an energy efficient pump speed control algorithm for controlling sump level. AFT Fathom is fluid dynamic simulation software for engineers, used to calculate pressure drop and flow distribution in liquid and low velocity gas piping and ducting systems. AFT is honored to assist students who are working on research projects so we  donate full licenses to assist with their education.

As an industry leading modeling, simulation and analysis software, engineers around the world have continuously utilized AFT Fathom since 1996. The software models piping and ducting systems for hydraulic engineering projects ranging from expansion verification to troubleshooting production issues. It is a popular tool that can be found in any successful engineer's toolbox as it's known for it's ease of use and highly accurate results.

Engineers appreciate the intuitive interface and can confidently make sustainable models they can pass on to future project engineers. 

In their paper, Dubey and Goossen say, "In general, savings in pump energy can be achieved in two main ways. One is by designing more efficient pumps. Another, discussed and presented here, is improving pump performance with effective control strategies." In this paper, the duo reports a new control algorithm for sump pumping systems, for example in wastewater treatment plants, that results in up to 4 % savings compared to the currently used control algorithms.

Applied Flow Technology values young engineers' ingenuity and this dynamic duo is no exception. This project is ongoing and we look forward to seeing how these bright minds use AFT Fathom to contribute to future energy reduction. 


Paper Title: Investigation of an Energy Efficient Pump Speed Control Algorithm For Controlling Sump Level

Abstract: This paper explores a new nonlinear control algorithm for variable speed centrifugal pumps at water/wastewater pump stations that leads to specific energy savings over the conventional linear one. The algorithm is useful for facilities where pump speed is a linear function of liquid level in order to transport fluid and smooth inflow peaks. A non-linearity in the form of a quadratic term is added to the conventional linear one in order to produce efficiency gains, with a single parameter, curvature, varied to optimize energy savings. Results obtained by implementing the new algorithm on a pilot-scale pump station show significant energy savings for fixed pump flow, with a parabolic correlation of specific energy savings versus curvature of the nonlinear quadratic determined. In addition, the cost of implementing this algorithm is minimal to none, so the work presented has major industrial potential.


Read the full paper here

AFT Arrow 7 Now Available

COLORADO SPRINGS, Colo., USA, July 31, 2018 -- AFT Arrow 7 has been released and it incorporates several new features Engineers and Managers have been asking for. If you engineer gas systems, AFT Arrow can help you work smarter. It's an awesome software tool that models, simulates, and analyzes pressure calculations and flow distribution in gas piping and/or ducting systems.

A few new features you might find interesting include:

  • Import piping layouts from CAESAR II® Neutral files
  • Import Piping Component Files(*.pcf) from SmartPlant®CADWorx®AutoCAD Plant 3D, and others.
  • EPANET import / export
  • Enhanced Excel integration including the new Excel Export Manager
  • Utilize 2D or isometric user interface
  • Clearer data entry for centrifugal compressor, reciprocating compressor and fans in the Compressor/Fan Property window
  • Updated Relief Valve specification with opening and closing profiles
  • Enhanced heat transfer including external convection coefficient calculation, buried pipe heat transfer, and heat tracing


Click HERE to view all of the new AFT Arrow 7 features.


Where did the name AFT Arrow Come From?

AFT Founder and President, Trey Walters, wrote a blog about the name a few years ago., It goes something like this:

When AFT Fathom was released in early 1994 we received many requests for a version which performed compressible flow modeling in pipe networks. When I started Applied Flow Technology in 1993 I knew AFT would develop a product for compressible pipe flow. So work on AFT Arrow began in 1994 soon after AFT Fathom 1.0 was released. However, he found out first hand what all fluid flow engineers already know - gas flow calculations are much harder than liquid flow. Especially in pipe networks.

But what should AFT's second software product be called?

I remember coming up with twenty different names to choose from. I can't remember hardly any of them but I do remember one of them being "Stratus". So AFT Arrow might have become AFT Stratus if I had made that rather misguided choice in 1995.

But then a moment of fate intervened.

I was working heavy hours in those days and my wife decided to take our young children to visit grandparents and I took them to the airport to send them on their way. On the way back home - AFT's office was in the basement of our home in those days - I was driving on the highway and passed an RV (a "recreatioanl vehicle" for international readers - it is like a mobile vacation home).

The brand name for the RV displayed in large letters on its back was "Arrow". And like an arrow which pierced me from out of the blue, I immediately realized AFT's second product would be called "AFT Arrow".

As challenging as it was to find a name for AFT Arrow, developing the product was even more challenging. I did not want to settle for a simplified ideal-gas, adiabatic-type of solution methodology to which other software companies have resorted. I wanted the whole thing - heat transfer, real gas modeling and fully capable sonically choked modeling capability. This took considerable effort and research, including the development of many highly innovative and proprietary solution techniques. In the end AFT Arrow was commercially released in October, 1995. Orders surged immediately because of the market awareness already created by AFT Fathom.

Today we are proud to offer AFT Arrow as the most accurate and capable compressible pipe flow software available on the market.


How can you learn more?

We have several options for you to try or inspect the capabilities of our software products including the product pages, features page, view an Introduction to AFT Arrow webinar, or even download a limited demo. The best of these options is a free evaluation license so you can see the full extent of this powerful software. Contact us at This email address is being protected from spambots. You need JavaScript enabled to view it. to request a license.