  A new vertical water tunnel with global temperature control and the
possibility for bubble and local heat & mass injection has been designed and
constructed. The new facility offers the possibility to accurately study heat
and mass transfer in turbulent multiphase flow (gas volume fraction up to
$8\%$) with a Reynolds-number range from $1.5 \times 10^4$ to $3 \times 10^5$
in the case of water at room temperature. The tunnel is made of high-grade
stainless steel permitting the use of salt solutions in excess of 15$\%$ mass
fraction. The tunnel has a volume of 300 liters. The tunnel has three
interchangeable measurement sections of $1$ m height but with different cross
sections ($0.3 \times 0.04 m^2$, $0.3 \times 0.06 m^2$, $0.3 \times 0.08 m^2$).
The glass vertical measurement sections allow for optical access to the flow,
enabling techniques such as laser Doppler anemometry, particle image
velocimetry, particle tracking velocimetry, and laser-induced fluorescent
imaging. Local sensors can be introduced from the top and can be traversed
using a built-in traverse system, allowing for e.g. local temperature,
hot-wire, or local phase measurements. Combined with simultaneous velocity
measurements, the local heat flux in single phase and two phase turbulent flows
can thus be studied quantitatvely and precisely.
