Particle Image Velocimetry (PIV) experiment of the buoyant flow field of a thermal chimney model designed for geothermal power plants

Figures & data

Figure 1. Geothermal application of thermal chimney

Figure 2. Diagram of PIV experiment setup

Figure 3. PIV laser illuminating and seeding photos

Figure 4. Averaged local velocity magnitude above single-row cylinders of 100°C including (a) PIV map – velocity magnitude contours and velocity vectors (b) data of |V| extracted at several distances from the heaters

Figure 5. Turbulent kinetic energy at different downstream distance above single-row cylinders of 100°C

Figure 6. Averaged air velocity (|V|) above double-row cylinders as the upper row heated to (a)~(c)60°C~140°C with row distance of 2D (d)~(f) 60°C~140°C with row distance of 5D (g)~(i) 140°Cwith row distance of 8D

Table 1. Averaged air velocity above double-row cylinders (m/s)

	Tuc = 60°C				Tuc = 100°C				Tuc = 140°C
	Height 5D	Height 10D	Height 15D	Height 20D	Height 5D	Height 10D	Height 15D	Height 20D	Height 5D	Height 10D	Height 15D	Height 20D
Row Distance 2D	0.268	0.256	0.272	0.295	0.295	0.266	0.283	0.316	0.319	0.336	0.350	0.376
Row Distance 5D	0.270	0.279	0.301	0.322	0.297	0.300	0.328	0.346	0.320	0.338	0.366	0.385
Row Distance 8D	0.276	0.280	0.308	-	0.311	0.316	0.346	-	0.357	0.347	0.381	-

Figure 7. Comparison of averaged air velocity above double-row and single-row cylinders

Table 2. TKE above double-row cylinders (1e-3) (m²/s²)

	Tuc = 60°C				Tuc = 100°C					Tuc = 140°C
	Height 5D	Height 10D	Height 15D	Height 20D		Height 5D	Height 10D	Height 15D	Height 20D		Height 5D	Height 10D	Height 15D	Height 20D
Row Distance 2D	5.7	2.5	1.4	1		8	3.4	1.7	1.1		9	3.6	1.9	1.4
Row Distance 5D	3.5	1	0.6	0.4		4	1.3	0.8	0.5		5	1.3	0.8	0.5
Row Distance 8D	3.2	0.8	0.6			3.8	1.1	0.8			4.8	1.2	0.8

Figure 8. Turbulent kinetic energy (TKE) above double-row cylinders as the upper row heated to (a)~(c)60°C~140°C with row distance of 2D (d)~(f) 60°C~140°C with row distance of 5D (g)~(i) 140°Cwith row distance of 8D

Figure 9. Vorticity field above double-row and single-row cylinders

Table

Abbreviation	Full Name
PIV	Particle image velocimetry
PID	Proportional integral derivative
TKE	Turbulent kinetic energy
Tc	Cylinder surface temperature in the single-row case (°C)
Tuc	Surface temperature of upper row cylinder (°C)
Tlc	Surface temperature of lower row cylinder (°C)
|V|	Local velocity magnitude (m/s)
$v_x$ and $v_y$	Root-mean-square (RMS) of x- and y- velocity component (m/s)