Project 001 · Afterburning turbojet
Project Jotun
An engine named for a force larger than ourselves. Designed from first principles. Built by students.
Explore the system ↓
I · THE OBJECTIVE
What is Jotun?
A complete gas turbine.
From a blank page.
Jotun is Jet NTNU’s first engine programme: a compact turbojet with an afterburner, conceived as a six-station system spanning inlet, compression, combustion, turbine, reheat, and exhaust. The project connects thermodynamics, aerodynamics, combustion, structures, manufacturing, controls, and testing in one machine.
The figures below are preliminary point-design targets from the current concept deck. They will evolve as analysis and testing mature.
The flowpath
Six stations.
One system.
Inlet
Delivers controlled airflow to the compressor.
Compressor
Adds stagnation enthalpy and raises total pressure.
Combustor
Adds heat through four parallel flame cans.
Turbine
Extracts the work required to drive compression.
Afterburner
Reheats the exhaust stream for additional velocity.
Nozzle
Converts the remaining pressure and heat into thrust.
02 · Compression
Making pressure
from motion.
The compressor converts shaft work into pressure. Jotun’s design study considers both centrifugal and multistage axial architectures, using Euler work, velocity triangles, loading, flow coefficient, reaction, diffusion limits, and slip to connect blade speed to real pressure rise.
- Nominal pressure-ratio target: 3:1
- Centrifugal study: slip and real exit swirl
- Axial study: stage loading, reaction, de Haller limit, and stage stacking
03 · Combustion
Four flames.
One purpose.
Four can combustors operate in parallel. Each can receives approximately one quarter of the core flow and divides it between primary, secondary, and dilution zones to establish a stable flame, complete combustion, and shape the turbine inlet temperature.
- Target turbine inlet temperature: 1000 K
- Preliminary fuel–air ratio: approximately 0.013
- Lean overall equivalence ratio: approximately 0.20
- Pressure loss and liner durability remain central design constraints
04 · Turbine
The critical
balance.
The turbine must extract exactly enough work to drive the compressor while surviving the engine’s most demanding combination of temperature, rotational speed, and centrifugal load. Work matching ties both machines to the same shaft.
- Uncooled hot-section concept
- Blade-root stress governed by material, geometry, and speed
- Reaction, loading, and flow coefficient shape the stage
- Static-test duty cycle prioritises thermal-fatigue management
05–06 · Reheat and exhaust
Extra heat.
Useful velocity.
Afterburner target
Heating the turbine exhaust toward 1300 K is estimated in the concept deck to increase exhaust velocity by roughly 23%. The duct must remain at low Mach number before reheat because Rayleigh heating drives the flow toward thermal choking.
Critical pressure ratio
The nozzle study uses a critical pressure ratio near 1.85 as its choking threshold. The final throat area and operating state must be matched to the verified cycle and compressor map before the nozzle geometry is closed.
How we build
Design what matters.
Buy what must work.
Static first
Controlled spool-up, approximately one minute at operating condition, and spool-down create a disciplined first test envelope.
Thermal realism
An uncooled hot section keeps turbine inlet temperature near 1000 K. Thermal-barrier-coated Inconel is considered for the 1300 K afterburner liner.
Budget discipline
The preliminary NOK 100,000 plan favours student-designed components and selectively purchases parts where reliability demands it.
The work continues