Press Release: PADT Awarded U.S. Army Phase I SBIR Grant for Combustor Geometry Research Using 3D Printing, Simulation, and Product Development

We are pleased to announce that the US Army has awarded PADT a Phase I SBIR Grant to explore novel geometries for combustor cooling holes. This is our 15th SBIR/STTR win.

We are excited about this win because it is a project that combines Additive Manufacturing, CFD and Thermal Simulation, and Design in one project. And to make it even better, the work is being done in conjunction with our largest customer, Honeywell Aerospace.

We look forward to getting started on this first phase where we will explore options and then applying for a larger Phase II grant to conduct more thorough simulation then build and test the options we uncover in this phase.

Read more below. The official press release is here for HTML and here for PDF.

If you have any needs to explore new solutions or new geometries using Additive Manufacturing or applying advanced simulation to drive new and unique designs, please contact us at 480.813.4884 or

PADT Awarded U.S. Army Phase I SBIR Grant for Combustor Geometry Research Using 3D Printing, Simulation, and Product Development

The Project Involves the Development of Sand-Plugging Resistant Metallic Combustor Liners

TEMPE, Ariz., August 15, 2019 ─ In recognition of its continued excellence and expertise in 3D printing, simulation, and product development, PADT announced today it has been awarded a $107,750 U.S. Army Phase I Small Business Innovation Research (SBIR) grant. With the support of Honeywell Aerospace, PADT’s research will focus on the development of gas turbine engine combustor liners that are resistant to being clogged with sand.  The purpose of this research is to reduce downtime and improve the readiness of the U.S. Army’s critical helicopters operating in remote locations where dirt and sand can enter their engines.  

“PADT has supported advanced research in a wide variety of fields which have centered around various applications of our services,” said Eric Miller, co-founder and principal, PADT. “We’re especially proud of this award because it requires the use of our three main areas of expertise, 3D printing, simulation and product development. Our team is uniquely capable of combining these three disciplines to develop a novel solution to a problem that impacts the readiness of our armed forces.”

The challenge PADT will be solving is when helicopters are exposed to environments with high concentrations of dust, they can accumulate micro-particles in the engine that clog the metal liner of the engine’s combustor. Combustors are where fuel is burned to produce heat that powers the gas turbine engine. To cool the combustor, thousands of small holes are drilled in the wall, or liner, and cooling air is forced through them. If these holes become blocked, the combustor overheats and can be damaged.  Blockage can only be remedied by taking the engine apart to replace the combustor. These repairs cause long-term downtime and significantly reduce readiness of the Army’s fleets.

PADT will design various cooling hole geometries and simulate how susceptible they are to clogging using advanced computational fluid dynamics (CFD) simulation tools. Once the most-promising designs have been identified through simulation, sample coupons will be metal 3D printed and sent to a test facility to verify their effectiveness.  Additionally, PADT will experiment with ceramic coating processes on the test coupons to determine the best way to thermally protect the 3D printed geometries.

“When we developed new shapes for holes in the past, we had no way to make them using traditional manufacturing,” said Sina Ghods, principal investigator, PADT. “The application of metal additive manufacturing gives PADT an opportunity to create shapes we could never consider to solve a complex challenge for the U.S. Army. It also gives us a chance to demonstrate the innovation and growth of the 3D printing industry and its applications for harsh, real-world environments.”

Honeywell joined PADT to support this research because it is well aligned with the company’s Gas Turbine Engine products. The outcome of this research has the potential to significantly improve the performance of the company’s engines operating in regions with high dust concentrations.

This will be PADT’s 15th SBIR/Small Business Technology Transfer (STTR) award since the company was founded in 1994. In August 2018, the company, in partnership with Arizona State University, was awarded a $127,000 STTR Phase I Grant from NASA to accelerate biomimicry research, the study of 3D printing objects that resemble strong and light structures found in nature such as honeycombs or bamboo.

To learn more about PADT and its advanced capabilities, please visit

About Phoenix Analysis and Design Technologies

Phoenix Analysis and Design Technologies, Inc. (PADT) is an engineering product and services company that focuses on helping customers who develop physical products by providing Numerical Simulation, Product Development, and 3D Printing solutions. PADT’s worldwide reputation for technical excellence and experienced staff is based on its proven record of building long-term win-win partnerships with vendors and customers. Since its establishment in 1994, companies have relied on PADT because “We Make Innovation Work.” With over 80 employees, PADT services customers from its headquarters at the Arizona State University Research Park in Tempe, Arizona, and from offices in Torrance, California, Littleton, Colorado, Albuquerque, New Mexico, Austin, Texas, and Murray, Utah, as well as through staff members located around the country. More information on PADT can be found at

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All Things ANSYS 020 – Modeling Flow & Heat Transfer with Flownex


Published on: September 10th, 2018
With: Eric Miller, Luke Davidson, Vincent Britz, and Farai Hetze
Description: In this episode your host and Co-Founder of PADT, Eric Miller is joined by Luke Davidson and Vincent Britz of M-Tech, and Farai Hetze from CFX-Berlin, for an interview on the what Flownex is, it’s capabilities for modeling flow and heat transfer, and how it works with ANSYS products. All that, followed by an update on news and events in the respective worlds of ANSYS and PADT.

If you have any questions, comments, or would like to suggest a topic for the next episode, shoot us an email at we would love to hear from you!



Making Thermal Contact Conductance a Parameter in ANSYS Mechanical 18.0 and Earlier with an APDL Command Object

A support request from one of our customers recently was for the ability to make Thermal Contact Conductance, which is sort of a reciprocal of thermal resistance at the contact interface, a parameter so it can be varied in a parametric study.  Unfortunately, this property of contact regions is not exposed as a parameter in the ANSYS Mechanical window like many other quantities are.

Fortunately, with ANSYS there is almost always a way……in this case we use the capability of an APDL (ANSYS Parametric Design Language) command object within ANSYS Mechanical.  This allows us to access additional functionality that isn’t exposed in the Mechanical menus.  This is a rare occurrence in the recent versions of ANSYS, but I thought this was a good example to explain how it is done including verifying that it works.

A key capability is that user-defined parameters within a command object have a ‘magic’ set of parameter names.  These names are ARG1, ARG2, ARG3, etc.  Eric Miller of PADT explained their use in a good PADT Focus blog posting back in 2013

In this application, we want to be able to vary the value of thermal contact conductance.  A low value means less heat will flow across the boundary between parts, while a high value means more heat will flow.  The default value is a calculated high value of conductance, meaning there is little to no resistance to heat flow across the contact boundary.

In order to make this work, we need to know how the thermal contact conductance is applied.  In fact, it is a property of the contact elements.  A quick look at the ANSYS Help for the CONTA174 or similar contact elements shows that the 14th field in the Real Constants is the defined value of TCC, the thermal contact conductance.  Real Constants are properties of elements that may need to be defined or may be optional values that can be defined.  Knowing that TCC is the 14th field in the real constant set, we can now build our APDL command object.

This is what the command object looks like, including some explanatory comments.  Everything after a “!” is a comment:

! Command object to parameterize thermal contact conductance
! by Ted Harris, PADT, Inc., 3/31/2017
! Note: This is just an example. It is up to the user to create and verify
! the concept for their own application.

! From the ANSYS help, we can see that real constant TCC is the 14th real constant for
! the 17X contact elements. Therefore, we can define an APDL parameter with the desired
! TCC value and then assign that parameter to the 14th real constant value.
! We use ARG1 in the Details view for this command snippet to define and enable the
! parameter to be used for TCC.

r,cid ! tells ANSYS we are defining real constants for this contact pair
! any values left blank will not be overwritten from defaults or those
! assigned by Mechanical. R command is used for values 1-6 of the real constants
rmore,,,,,, ! values 7-12 for this real constant set
rmore,,arg1 ! This assigned value of arg1 to 14th field of real constant

! Now repeat for target side to cover symmetric contact case
r,tid ! tells ANSYS we are defining real constants for this contact pair
! any values left blank will not be overwritten from defaults or those
! assigned by Mechanical. R command is used for values 1-6 of the real constants
rmore,,,,,, ! values 7-12 for this real constant set
rmore,,arg1 ! This assigned value of arg1 to 14th field of real constant

You may have noticed the ‘cid’ and ‘tid’ labels in the command object.  These identify the integer ‘pointers’ for the contact and target element types, respectively.  They also identify the contact and target real constant set number and material property number.  So how do we know what values of integers are used by ‘cid’ and ‘tid’ for a given contact region?  That’s part of the beauty of the command object: you don’t know the values of the cid and tid variables, but you alsp don’t need to know them.  ANSYS automatically plugs in the correct integer values for each contact pair simply by us putting the magic ‘cid’ and ‘tid’ labels in the command snippet.  The top of a command object within the contact branch will automatically contain these comments at the top, which explain it:

!   Commands inserted into this file will be executed just after the contact region definition.
!   The type number for the contact type is equal to the parameter “cid”.
!   The type number for the target type is equal to the parameter “tid”.
!   The real and mat number for the asymmetric contact pair is equal to the parameter “cid”.
!   The real and mat number for the symmetric contact pair(if it exists)
! is equal to the parameter “tid”.

Next, we need to know how to implement this in ANSYS Mechanical.  We start with a model of a ball valve assembly, using some simple geometry from one of our training classes.  The idea is that hot water passes through the valve represented by a constant temperature of 125 F.  There is a heat sink represented at the OD of the ends of the valve at a constant 74 degrees.  There is also some convection on most of the outer surfaces carrying some heat away.

The ball valve and the valve housing are separate parts and contact is used to allow heat to flow from the hotter ball valve into the cooler valve assembly:

Here is the command snippet associated with that contact region.  The ‘magic’ is the ARG1 parameter which is given an initial value in the Details view, BEFORE the P box is checked to make it a parameter.  Wherever we need to define the value of TCC in the command object, we use the ARG1 parameter name, as shown here:

Next, we verify that it actually works as expected.  Here I have setup a table of design points, with increasing values of TCC (ARG1).  The output parameter that is tracked is the minimum temperature on the inner surface of the valve housing, where it makes contact with the ball.  If conductance is low, little heat should flow so the housing remains cool.  If the conductance is high, more heat should flow into the housing making it hotter.  After solving all the design points in the Workbench window, we see that indeed that’s what happens:

And here is a log scale plot showing temperature rise with increasing TCC:

So, excluding the comments our command object is 6 lines long.  With those six lines of text as well as knowledge of how to use the ARG1 parameter, we now have thermal contact conductance which varies as a parameter.  This is a simple case and you will certainly want to test and verify for your own use.  Hopefully this helps with explaining the process and how it is done, including verification.