Introduction

In many automotive and industrial applications, the performance of pressure swirl atomizers can significantly affect efficiency, lubrication, combustion, or cooling. Yet many engineers are forced to make design choices based on assumptions or trial-and-error testing. Even small design changes—like modifying the outlet geometry of a nozzle—can lead to unpredictable changes in spray patterns.

Could a small geometric change to the nozzle lead to more optimal spray distribution?

To find out, we used Ansys Fluent’s Volume of Fluid (VOF) model to simulate and compare the spray characteristics of two nozzle designs under identical operating conditions in our upcoming webinar.

Comparing Two Nozzle Geometries Under Identical Conditions

Case 1: Straight Nozzle Design

This nozzle features a purely cylindrical exit with sharp edges, causing the fluid to exit in a tight jet. The nozzle bore has minimal transition, encouraging high-velocity discharge directly along the axial direction.

🔹Fluid Behavior

• • The sharp edge promotes shear-layer instabilities near the exit, initiating breakup after a short distance.

  • The flow remains cohesive longer, resulting in a more focused spray cone.

  • Atomization begins slightly downstream of the nozzle tip due to minimal upstream disturbance.

🔹Spray Pattern Outcome

• • The spray cone angle is narrower, forming a dense liquid core.

  • Ideal for applications where deep penetration or targeted impact is needed.

  • Less droplet dispersion observed on the bottom-plane slice, indicating a more centralized impact area.

Case 2: Rounded Nozzle Design

This variant features a rounded transition from the internal chamber to the outlet, smoothing the path for liquid flow. The curvature reduces flow separation and pressure drop spikes.

🔹Fluid Behavior

• • Flow accelerates more smoothly, reducing boundary-layer detachment and encouraging early primary breakup.
  • A more uniform pressure gradient along the nozzle wall leads to earlier destabilization of the jet.
  • Promotes a swirling, cone-like spray with a broader radius of influence.

🔹Spray Pattern Outcome

• • The resulting cone angle is wider, creating more surface area coverage.
  • Bottom-plane visualization shows increased droplet spread and more uniform impact pattern.
  • Better suited for applications like spray cooling, coating, or air-fuel mixing, where broad coverage is beneficial.

Key Takeaways from Geometry Comparison

• Straight Outlet (Case 1): Best for focused applications with concentrated spray delivery, such as fuel injection or targeted lubrication.

• Rounded Outlet (Case 2): More effective for applications requiring spray uniformity and wider coverage, such as surface treatment, cooling sprays, or environmental misting.

• Conclusion: Even small changes in geometry—like edge rounding—can dramatically alter the spray footprint, making CFD modeling an essential design step.

Want to see how these geometries behave in real time?
Join Dr. Ted Sperry’s webinar for a walkthrough of these simulation results in Ansys Fluent, and learn best practices for modeling pressure swirl atomizers.
Register now for the webinar

Introduction

From the smartphone in your pocket to satellites orbiting Earth, optics and photonics are transforming the way we live, communicate, and innovate. As devices become increasingly complex—combining nano- to micro-scale components, selecting the right optical simulation software is critical.

Ansys offers three powerful and complementary tools in its optics portfolio: SPEOS, Lumerical, and Zemax. While they all serve the optical design space, each is built for different levels of simulation, from chip to system to human perception. Understanding their differences will help ensure your team is using the most effective solution for your goals.

Ansys SPEOS: Real-World Light Simulation

Primary Focus: 3D lighting systems, human vision, and environmental interaction.

Best For: Engineers designing lighting systems, sensors, and displays that need to function correctly in real-world conditions.

Why Use It:

• Simulates how light behaves in real environments.
• Evaluates visibility, glare, and human eye perception.
• Ensures compliance with industry regulations (e.g., automotive lighting).
• Perfect for full 3D scene analysis, including camera and sensor packaging.

Example Use Case: Ensuring a car’s heads-up display (HUD) remains legible in all lighting conditions or verifying that a drone’s sensor accurately interprets glare in outdoor environments.

Ansys Lumerical: Photonics at the Nanoscale

Primary Focus: Photonic components, integrated circuits (PICs), and light-matter interaction at the nanoscale.

Best For: Designers of photonic communication systems, metamaterials, or CMOS sensors.

Why Use It:

• Multiphysics solvers for electromagnetic, thermal, and electronic effects.
• Models waveguides, gratings, quantum devices, and more.
• Ideal for datacom, optical interconnects, and pixel-level design.
• Enables chip-to-system simulations with full interoperability.

Example Use Case: Developing a photonic integrated circuit (PIC) for high-speed optical data transmission in datacenter equipment or optimizing nanostructures on an OLED display.

Ansys Zemax: Precision Optical System Design

Primary Focus: Imaging systems, lens design, and optical tolerancing.

Best For: Optical engineers building AR/VR systems, microscopes, telescopes, or consumer electronics lenses.

Why Use It:

• Combines sequential and non-sequential ray tracing in one UI.
• Offers comprehensive tolerancing and STOP (Structural, Thermal, Optical Performance) analysis.
• Integrates optical and mechanical design, reducing cross-team errors.
• Allows for precise manufacturability assessments from concept to production.

Example Use Case: Designing and optimizing the optical path of a VR headset lens, accounting for structural and thermal effects on image quality.

How They Compare

Want to see these tools in action?

Check out our upcoming webinars, including:

• Camera Development – Leveraging Zemax for lens design, Lumerical for image sensor optimization, and SPEOS for vision analysis.
• Photonic Integrated Circuits – Deep-dive into chip-level simulation with Lumerical, including packaging, yield analysis, and thermal stabilization.

Introduction

In the fast-paced world of engineering simulations, Ansys Rocky stands out as a game-changer for particle dynamics. Whether you’re working in mining, pharmaceuticals, agriculture, or any industry that deals with bulk materials, Ansys Rocky provides unmatched accuracy, speed, and scalability in Discrete Element Method (DEM) simulations.

As industries push the boundaries of digital engineering, integrating Ansys Rocky with CFD (Computational Fluid Dynamics), FEA (Finite Element Analysis), and Multiphysics solutions ensures a comprehensive approach to real-world problem-solving. In this blog, we’ll explore how Ansys Rocky is reshaping engineering design and how you can leverage it for optimized results.

What Makes Ansys Rocky Stand Out?

1. Advanced Particle Shapes and Breakage Modeling

Unlike traditional DEM tools that rely on spherical approximations, Ansys Rocky allows for realistic particle shapes, including clusters, fibers, and shells. This results in highly accurate predictions of bulk material behavior, leading to more reliable product designs and operational insights.

2. Seamless Multiphysics Integration

By integrating with Ansys Fluent and Ansys Mechanical, Ansys Rocky enables users to study:

• Fluid-particle interactions (ideal for industries like pharmaceuticals and food processing)
• Structural loads due to bulk materials (important in conveyor and mining applications)
• Thermal effects on particle flow This synergy provides engineers with a holistic understanding of how materials behave under various conditions.

3. GPU Acceleration for Faster Simulations

Time is money, and Ansys Rocky ensures maximum efficiency with its GPU-accelerated solver. Users experience up to 50x faster computation speeds compared to traditional CPU-based solvers, significantly reducing simulation time and enabling rapid design iterations.

4. Realistic Conveyor and Comminution Analysis

For industries dealing with bulk material transport, Ansys Rocky provides detailed conveyor belt wear analysis and crusher/grinder efficiency predictions. These insights help manufacturers optimize equipment lifespan, reduce downtime, and improve overall productivity.

Our exclusive webinar will walk through real-world case studies, demonstrate simulation workflows, and show how Rocky integrates with other Ansys tools effectively. 

Industry Applications

1. Mining and Material Handling

• Predict and mitigate conveyor belt wear and tear
• Optimize grinding and crushing efficiency
• Reduce maintenance costs and improve operational reliability

2. Pharmaceuticals and Food Processing

• Model tablet coating and powder mixing
• Improve granulation and capsule filling processes
• Enhance product uniformity and reduce waste

3. Agriculture and Fertilizer Production

• Simulate grain flow and storage behavior
• Optimize fertilizer blending and application processes
• Reduce handling losses and ensure product consistence

How to Get Started with Ansys Rocky

Step 1: Define Your Simulation Objectives

Identify what you want to achieve—whether it’s reducing equipment wear, optimizing material flow, or improving product consistency.

Step 2: Import and Set Up Geometry

Ansys Rocky allows direct CAD imports, making it easy to create accurate simulations with real-world geometries.

Step 3: Select the Right Particle Model

Choose from a variety of particle shapes and material properties to best represent your system.

Step 4: Run GPU-Accelerated Simulations

Leverage parallel processing for faster and more detailed results.

Step 5: Analyze and Optimize

Use Ansys Rocky’s visualization tools to interpret results and refine designs for maximum efficiency.

Conclusion: Why Ansys Rocky is a Must-Have for Engineers

Ansys Rocky is more than just a DEM tool—it’s a simulation powerhouse that bridges the gap between physics-based modeling and real-world applications. With advanced particle modeling, seamless multiphysics integration, and high-speed processing, it is a must-have solution for industries looking to innovate and optimize their bulk material handling processes.

If you’re ready to take your simulations to the next level, contact us today for a demo or trial of Ansys Rocky and see how it can transform your engineering workflow! Our upcoming webinar showcases the advanced simulation tool designed for modeling granular and discontinuous materials across industries like pharmaceuticals, mining, food processing, and manufacturing.

ANsIntroduction

In modern electrical engineering, circuit simulation tools play a crucial role in designing and verifying circuits before physical implementation. LTspice and Ansys Nexxim Circuit are two widely used simulation tools, each offering unique advantages for engineers. This blog explores their features, compares their performance, and highlights the best use cases for each.

Background: The Importance of Circuit Simulation

SPICE (Simulation Program with Integrated Circuit Emphasis) has been a cornerstone in circuit analysis since its inception. Over the years, multiple variations of SPICE have emerged, including ISPICE, HSPICE, PSPICE, and LTspice, each catering to different needs. Almost all electrical engineers have used SPICE-based tools for verifying circuit designs, debugging performance issues, and optimizing circuit parameters.

Project Overview: Comparing LTspice and Ansys Nexxim Circuit

For this study, a two-stage operational amplifier (op-amp) was simulated using both LTspice and Ansys Nexxim Circuit. The key design specifications included:

• Gain @ 1kHz > 40dB
• Unity Gain Frequency > 50kHz
• Phase Margin > 45˚
• Gain Margin > 10dB
• Quiescent Current ≅ 100µA
• Compensation Capacitor < 30pF
• Compensation Resistor < 1000kΩ
• MOSFET Model: 0.18µm CMOS

The primary goal was to determine how each tool handled the circuit simulation process, from defining models and parameters to analyzing compensated and uncompensated results.

LTspice: Strengths and Workflow

LTspice is a widely used, free circuit simulation tool developed by Analog Devices. It allows engineers to:

• Define subcircuits using .model for MOSFETs
• Assign design parameters (W/L ratios, bias voltages) using .param definitions
• Use hierarchical subcircuits for modular design
• Perform transient and frequency-domain analysis
• Visualize circuit behavior with node plotting

LTspice is known for its simplicity and efficiency, making it an excellent choice for small-to-medium-sized analog circuit designs.

Ansys Nexxim Circuit: Advanced Features and Workflow

Nexxim Circuit, a part of Ansys’ circuit simulation suite, offers all the capabilities of LTspice with additional advanced analysis features. Key capabilities include:

• Defining model blocks for MOSFETs
• Using project variables for W/L ratios and bias voltages
• Performing transient, frequency-domain, and DC sweep analysis
• Conducting signal integrity, resonant, and time-varying noise analysis
• Using structure blocks for trace and via modeling
• Co-simulating with FEM (Finite Element Method) analysis
• Parameterizing and optimizing circuit designs

Results: LTspice vs. Nexxim Circuit Performance

The two tools were used to simulate both uncompensated and compensated versions of the op-amp. The results showed that both LTspice and Nexxim Circuit provided comparable basic simulation accuracy. However, Nexxim’s Optimetrics feature allowed advanced optimization of the circuit parameters, leading to an improved design with minimized component values while maintaining target performance.

Conclusion: Which Tool Should You Use?

• Use LTspice if you need a free, straightforward SPICE simulation tool for basic analog circuit design and debugging.
• Use Ansys Nexxim Circuit if you require advanced analysis, signal integrity testing, co-simulation with FEM, and automated circuit optimization for high-performance applications.

For engineers working on high-speed digital circuits, RF applications, or signal integrity-focused designs, Nexxim Circuit is the superior choice due to its extended analysis capabilities and optimization features. However, LTspice remains a go-to tool for quick, effective circuit verification in analog and power electronics design. Want to see LTspice and Nexxim Circuit in action? Watch our detailed breakdown and simulation walkthrough on YouTube! If you’re interested in learning more about circuit simulation techniques and best practices, don’t miss our upcoming webinar on LTspice vs. Ansys Nexxim Circuit: Advanced Simulation Techniques.

Introduction

Torque is a fundamental aspect of fastening technology, ensuring that components remain securely connected under various loads and operating conditions. In threaded fastener assemblies, torque application must be carefully analyzed and controlled to prevent issues such as joint loosening, fatigue failure, or excessive stress on the materials involved. Engineers rely on torque analysis to optimize design, improve reliability, and enhance performance in mechanical assemblies ranging from automotive applications to aerospace and heavy machinery.

Understanding how torque is absorbed and distributed within a threaded assembly is essential for accurate predictions of joint behavior. This blog explores the three primary areas where torque is absorbed, introduces different simulation techniques available in Ansys Mechanical, and explains methods for validating torque using both traditional analytical approaches and modern computational tools. By leveraging these methodologies, engineers can make informed decisions that enhance the efficiency and safety of fastener assemblies.

Torque Distribution in Fastener Assemblies

Torque applied to a threaded fastener assembly is primarily absorbed in three main areas:

1. Underhead Friction
2. Thread Friction
3. Developing Clamping Force that holds components together

The net distribution of torque among these areas plays a crucial role in fastening integrity and performance.

Torque-Angle Relationship

The torque-angle of turn relationship is a valuable method for determining torque using traditional techniques, such as hand calculations. This approach helps engineers estimate torque with reasonable accuracy, ensuring secure fastener connections.

The net distribution of the torque in these 3 main areas is given as below:

Method 1: Helical Thread Trajectory Simulation

There are several techniques to simulate geometric interference from torque. One approach involves driving the parts in Ansys Discovery along the helical thread trajectory. This method simulates both rotational and axial movement due to torque, creating geometric overlap. To achieve accurate results, the contact offset is set to zero, allowing the actual geometric interference to represent torque application.

Method 2: Contact-Based Interference Simulation

Second method involves simulating applied torque through contact-based interference. This technique models torque effects by defining contact conditions where the original geometry shows parts merely touching. The simulation then resolves the resulting interference forces.

There are couple of different ways to validate torque; one is using traditional method such as hand calculations and second method is to use CAE, in this case, using Ansys.

Traditional Methods to determine torque:

Method 1 is to use the torque-angle of turn relationship as shown below.

Method 2 is to take the contact element data and output via ETABLE, and the contact pressure is multiplied with contact elements to contact normal force which is then multiplied by friction coefficient to get shear force on each contact element. The shear force is then multiplied with distance of contact element (Centroid) from axis to get torque on contact element and then it’s summed from all contact elements to get overall torque.

Methods to Validate Torque

The Ansys methodology also offers several options. One way is to output solution result tracker as shown illustrated below:

Second way would be to use an MAPDL macro that will deliver the results automatically.

Summary

The difference in the two ways demonstrated here; using the result tracker, Ansys is assuming unity friction coefficient, so user would need to scale the results with appropriate friction coefficient as demonstrated here. For the MAPDL macro, it’s fully automated, the user plugs in the friction coefficient and the total torque is delivered.

The techniques presented here provide ample options for the user to determine total torque; the automated ways using Ansys are accurate and the traditional methods provide quick and dirty answer that gives us a ballpark estimate for a good sanity check. One can use this technique to not only validate torque, but also calibrate the torque if actual angle of turn is unknown through couple of design iteration runs.

The techniques discussed provide engineers with multiple options for torque validation:

• Ansys-based automated methods offer high accuracy and efficiency.
• Traditional hand calculations serve as quick, approximate checks.

Beyond torque validation, these approaches can also help calibrate torque in cases where the actual angle of turn is unknown. By performing multiple design iterations, engineers can refine torque estimates and optimize fastener performance in real-world applications.

Additional Resources

For more insights, check out the following resources:

• Watch a detailed video on torque analysis on YouTube
• Watch full webinar on evaluating torque values on threaded fasterners 

Recently I had an amazing reunion with my friends and mentors, Dwight Yoder and Steve Jordan, in Sanibel Island, FL. Our wives, Carolyn, Donna, and Anne joined us in this remarkable event. Steve and Dwight have been my friends and mentors my entire professional life.

In 1977 Steve and his business partners, Mike Apostal and Chuck Ritter, founded Jordan, Apostal, Ritter Associates Engineering Mechanics Consultants in Davisville, RI.  JAR began to do engineering mechanics consulting for the AMOCO Research Center in Tulsa, OK. JAR and AMOCO were two of the first companies to utilize the finite element method to model the lower part of the drill string, called the bottom hole assembly, to predict directional drilling for the oil and gas industry. JAR’s work with AMOCO led to Steve, Mike and Chuck creating Drilling Resources Development Corporation in Tulsa, now DRD Technology, to work with AMOCO to develop a drilling simulator to model the entire drilling process in real time. Steve hired Dwight and me in 1981 to join DRD, and our work with AMOCO led to software development for other oil and gas companies. Ultimately DRD developed its own commercial suite of software tools for the oil and gas industry, Wellplan™, which we sold worldwide.

Because of a relationship with John Swanson, founder of Ansys, JAR and Drilling Resources Development Corporation became Ansys Support Distributors in 1984. JAR later became Ansys East in the 1990’s. Steve, Mike and Chuck also founded Concurrent Engineering Corporation in Minneapolis, MN in the 1990’s, which later became Ansys Minneapolis. Earlier in his career Steve worked with several of the pioneers of the early finite element industry including Richard Gallagher of Bell Aerosystems, Cornell University and University of AZ; Richard MacNeal of MSC (NASTRAN); Pedro Marcal and Bob Melosh of MARC Analysis; and David Hibbitt of Hibbitt, Karlsson, and Sorenson, developer of ABAQUS. Steve offered me the opportunity to have a career in the field of engineering simulation, and he mentored me closely my first two decades at DRD.

Dwight has also been my friend and mentor my entire career. In 1995 DRD sold Wellplan to Landmark Graphics, a division of Halliburton. Dwight and I were colleagues at DRD until 1995 when Dwight left DRD to become a Vice President at Landmark Graphics. Dwight later returned to work at DRD before leaving DRD a second time to pursue other interests. Dwight remains a minority owner of DRD. Dwight and Carolyn are god parents to Anne’s and my daughters, Renee and Morgan.

This Sanibel reunion was the first in-person one for Dwight, Steve, and me in 26 years, and the experience was as if we had never been apart.  What a reunion!