How do you maintain a constant load on the cpu?

I am looking at my phone with a thermal camera to watch the external heat distribution as I attempt to hold it at a constant high load.

What I need to do is hold the CPU at a constant load over the span of about 30 mins, I have achieved this with relative success using the two "burner" apps available on google play. I paired this with SetCPU to max out the allowable core frequencies.

I have used HWMonitor PRO to view the temp sensor values and record them on my PC.

Does anyone know if there is an app available that applies a repeatably constant load or how one would begin to do so through programming? The main issue I am finding is that the burner apps will shut down after a certain time (or temperature) and don't feel very consistent.

Any help is greatly appreciated!