Service overview
Fluid flow, heat transfer, multiphase, aerodynamic and turbulence simulation. This service is part of that division and is scoped individually around what you need to learn, decide or publish.
Heat transfer problems are often decisive for reliability: an electronic component that runs too hot ages quickly, a battery with a temperature gradient wears unevenly, a heat treatment with poor uniformity gives variable properties. Thermal simulation predicts temperature fields and heat flows so that designs can be checked and improved before hardware is built.
Heat moves by conduction, convection and radiation, and in many real systems all three act together and interact with fluid flow and material properties. The simulation approach must reflect which mechanisms dominate. Simple resistance networks provide quick checks and intuition, while conjugate heat transfer models resolve the coupling between solid conduction and fluid convection. Good practice uses both and uses measured data to calibrate and validate.
If you plan to publish the outcome, see manuscript & publication support, for example computational & simulation manuscripts or original research article writing.
What this service covers
Problems this service can address
- Hot spots whose cause is not obvious
- Uncertain heat-transfer coefficients and contact resistances
- Transient behaviour that steady-state estimates miss
Methods and analytical approaches
- Steady and transient conduction analysis
- Conjugate heat transfer modelling
- Radiation and natural or forced convection treatment
- Thermal-resistance network cross-checks
Applications
- Electronics and battery cooling
- Heat exchangers and thermal storage
- Thermal processing of materials
Relevant engineering disciplines
Scope, inputs and deliverables
Scope of work
- Definition of the physics, geometry and quantities of interest
- Model set-up with verification and, where data allow, validation
- Parametric or sensitivity studies agreed at scoping
- Results and documentation suitable for reports or publication
- Feasibility check on: geometry and materials with thermal properties
Typical inputs required from you
- Geometry and materials with thermal properties
- Heat loads and ambient conditions
- Temperature measurements for validation
Deliverables
- Temperature and heat-flux fields
- Thermal bottleneck identification
- Report with stated assumptions
Highly specialised requests are first checked for feasibility from this information. Please do not send confidential data through the public form; describe it first and agree secure transfer afterwards.
Project workflow and method
- 01Enquiry and requirement assessment
- 02Technical scoping and proposal
- 03Execution
- 04Quality review and delivery, with an agreed round of revisions
Read the full project workflow.
In depth: how the work is done
Conduction analysis
Conduction in solids is governed by Fourier's law and the heat equation. Steady analyses reveal temperature distributions and hot spots; transient analyses show heating and cooling behaviour and the time to reach steady operation. Temperature-dependent conductivity, anisotropy in composites and contact resistance between components are significant in practice and must be represented or bounded. Interface thermal resistance is often the largest uncertainty, so we discuss how to characterise it and test sensitivity.
Convection: natural and forced
Convective heat transfer coefficients are not material constants. They depend on flow regime, geometry and orientation. For simple geometries, correlations in terms of Nusselt, Reynolds and Rayleigh numbers provide good estimates. For complex geometries, CFD computes the flow and heat transfer directly. In natural convection, buoyancy-driven flow can be sensitive to boundary conditions and to the turbulence treatment, and transient behaviour can be important. We choose between prescribed coefficients and resolved flow according to the accuracy needed.
Radiation
Radiative exchange becomes important at high temperatures and in enclosures with low convective transfer. Surface emissivity, view factors and participating media determine the heat exchanged. Surface-to-surface and more detailed models are chosen according to the geometry and the importance of radiation. Emissivity values vary with surface finish and ageing, so sources are documented and sensitivity tested.
Conjugate heat transfer and thermal management
Conjugate heat transfer simulates the solid and fluid regions together, so the heat flux at the interface follows from the solution instead of being assumed. This is essential for heat sinks, heat exchangers and cooled components. Thermal management studies compare design options such as fin geometry, spreader materials or airflow paths against temperature limits, and consider operating scenarios including worst-case ambient and transient loads.
Cross-checks with resistance networks and measurements
Thermal resistance networks give a simple independent check on detailed results: total resistance from heat source to ambient should be similar to what the simulation implies. Measurements from thermocouples or infrared imaging provide validation, with attention to sensor placement, contact errors and emissivity assumptions for infrared. Differences between model and measurement are traced to specific assumptions and the model is updated accordingly.
Quality control and good practice
Quality-control approach
- Verification: mesh, time-step and solver sensitivity are examined before results are reported.
- Validation: results are compared with measurements or reference solutions where these exist, and the absence of such data is stated.
- Boundary conditions and material or fluid properties are recorded with their sources.
- Sensitivity to the least certain inputs is shown or explained.
Common pitfalls this service helps avoid
- Assuming a fixed convection coefficient. Coefficients depend on the local flow and temperature and can differ greatly from textbook values.
- Neglecting contact resistance. Interfaces between parts can dominate the thermal path and are poorly known without measurement.
- Ignoring temperature-dependent properties. Conductivity, viscosity and specific heat can change enough to affect results over wide temperature ranges.
- Wrong emissivity assumptions. Surface condition changes radiative exchange and infrared temperature readings.
What good reporting looks like
A thermal report states the heat sources and loads, material properties with sources, boundary conditions including ambient and cooling assumptions, the model type and mesh, steady or transient results, temperature distributions and critical locations against limits, validation or cross-check results and the sensitivity to uncertain inputs. It gives margins relative to the limits supplied by the client and identifies the uncertainties that most threaten those margins.
An illustrative scenario
Hypothetical example written for explanation. It is not a client case, a result or a testimonial.
Suppose a researcher wants to reduce the peak temperature of a power module on a finned heat sink. A resistance network suggests that the interface material between module and sink is the biggest contributor to the temperature rise. A conjugate heat transfer model confirms this and shows that the fin spacing is nearly optimal for the available airflow. The study recommends measuring the interface resistance, since its uncertainty is larger than the benefit of any fin change, and reports the peak temperature as a range reflecting that uncertainty.
Questions to settle before you begin
- What is the maximum acceptable temperature, and where?
- Which heat transfer mechanisms dominate?
- How well do I know heat generation and interface resistances?
- Is the load steady or transient?
- What temperature measurements can I use for validation?
Key terms
- Conjugate heat transfer
- Simultaneous solution of heat conduction in solids and convection in fluids.
- Nusselt number
- A dimensionless measure of convective heat transfer relative to conduction.
- Emissivity
- The effectiveness of a surface in emitting thermal radiation.
- Contact resistance
- Resistance to heat flow across an interface between two bodies.
- View factor
- The fraction of radiation leaving one surface that reaches another.
Working together on Computational Fluid Dynamics (CFD) projects
CFD engagements start with a flow-physics review: expected regime, quantities of interest, available geometry and the measurements that could validate results. A coarse pilot simulation can check set-up and cost before the full study. We ask for geometry in a standard exchange format or dimensioned drawings, fluid properties, boundary conditions and any test data. Reports include mesh and model sensitivity so that you can see how much the answer depends on numerical choices. Results are presented as engineering quantities with units, and limits of validity are stated explicitly.
Frequently asked questions
How reliable are thermal results without measurements?
They rely on assumed coefficients and properties, so we label them clearly and run sensitivity checks. Measured data improve credibility considerably.
Can you model battery or electronics cooling?
Yes, from the information you can provide about heat generation, geometry and cooling. Accuracy depends on how well heat generation and interface resistances are known.
Do you need detailed internal geometry?
Not always. Simplified internal representations can be used when justified, and the effect of simplification should be assessed.
Can you include phase change?
Phase-change problems such as melting and solidification can be modelled using appropriate methods when material data are available.
How is experimental validation handled?
Test data you supply are compared with the model. If none exist, we can recommend a measurement plan.
How is this service scoped and priced?
After your enquiry we review what you need, ask for missing information and send a written scope and quotation. Price depends on complexity, deliverables and timeline. See the project workflow.