radiation issues in electronic cooling with SW flow simulation

Hello together,

first let me say sorry for my englisch. I`m a German student and I`m working on a projekt for my Thesis.

The task is to simulate the thermal situation of an industrial camera with flow simulation 2018. At the moment I´m not really sure if i need radiation in my simulation. In most of the turorial they say if the temperature is not realy high I can ignore the radiation. My first simple calculation and simulations are showing someting different.

The camera casing is made of anodized aluminium (silver and black). It`s size about 30x30 mm. The temperature of the camera is abaut 70 °C and 50 °C environment temperature. The power consumption is 2,5W. It`s n external study and ther`s only natural convection (and radiation).

So here are my questions:

1. Could it be possible that radiation is about 40 % of the over all heat transfer?

2. Should I use wall or wall to ambient or for the inner part wall and the outside of the housing wall to ambient?

3. I`m not really sure about the emissivity of my surface. the literature values have a high range between 0.5 and 0.95.

Thanks a lot

Greetings

SolidworksFlow Simulation