Figures & data
Figure 2. Different wire structure heat exchangers with high aspect ratio tested for thermal–hydraulic performance: (a) continuous wire structure; (b) pin fin structure; and (c) woven wire structure (adopted from [Citation18,Citation21,Citation22]).
![Figure 2. Different wire structure heat exchangers with high aspect ratio tested for thermal–hydraulic performance: (a) continuous wire structure; (b) pin fin structure; and (c) woven wire structure (adopted from [Citation18,Citation21,Citation22]).](/cms/asset/a95c6636-2817-4614-83f0-4a88e8ee50d5/unht_a_1562741_f0002_c.jpg)
Figure 4. Boundary conditions of the in-line (a) and staggered (b) cross-section model [Citation18].
![Figure 4. Boundary conditions of the in-line (a) and staggered (b) cross-section model [Citation18].](/cms/asset/27dfb765-e7b6-4146-8d2c-ca2b46f0cba1/unht_a_1562741_f0004_c.jpg)
Table 1. Definition of nondimensional input parameters to simulation model with minimal and maximal values in parametric study.
Table 2. Grid Convergence Index (GCI) based on Richardson method [Citation27] for Nusselt number and friction factor.
Figure 6. Pressure difference, velocity, and temperature of a 2D in-line wire structure simulation with = 10,
= 3,
= 20, and
. Contour lines for pressure difference are equally distributed. Velocity streamlines are colored based on the temperature scale.
![Figure 6. Pressure difference, velocity, and temperature of a 2D in-line wire structure simulation with a = 10, b = 3, Rest = 20, and nwires=20. Contour lines for pressure difference are equally distributed. Velocity streamlines are colored based on the temperature scale.](/cms/asset/9059f500-f254-428c-884f-be4d2aaeaeef/unht_a_1562741_f0006_c.jpg)
Figure 7. Nusselt number and Fanning friction factor of an in-line wire structure for a developed flow as a function of Reynolds number and geometry parameters and
.
![Figure 7. Nusselt number and Fanning friction factor of an in-line wire structure for a developed flow as a function of Reynolds number and geometry parameters a and b.](/cms/asset/4e928c72-15cf-4145-b086-34577c81a15e/unht_a_1562741_f0007_b.jpg)
Figure 8. Correlated global (solid line) and local (dashed line) Nusselt number, and
, respectively, for an in-line wire arrangement, as a function of the number of wires based on the simulated global data points (squares) for
and fixed values for
. Downstream of the thermal entrance length (dotted line), the flow is declared as thermally developed.
![Figure 8. Correlated global (solid line) and local (dashed line) Nusselt number, Nust and Nust,local, respectively, for an in-line wire arrangement, as a function of the number of wires based on the simulated global data points (squares) for Nust and fixed values for a=10,b=3,Rest=20. Downstream of the thermal entrance length (dotted line), the flow is declared as thermally developed.](/cms/asset/44ccd122-46db-4d58-9e88-4f93d4ac4708/unht_a_1562741_f0008_b.jpg)
Figure 9. Correlated global (solid line) and local (dashed line) friction factor, and
, respectively, for an in-line wire arrangement as a function of the number of wires based on the simulated global data points (squares) for
and fixed values for
. Downstream of hydraulic entrance length (dotted line), the flow is declared as hydraulically developed; in-line arrangement.
![Figure 9. Correlated global (solid line) and local (dashed line) friction factor, fst and fst,local, respectively, for an in-line wire arrangement as a function of the number of wires based on the simulated global data points (squares) for fst and fixed values for a=10,b=3,Rest=20. Downstream of hydraulic entrance length (dotted line), the flow is declared as hydraulically developed; in-line arrangement.](/cms/asset/ea011353-5333-4762-bf2d-6c3c2be9064c/unht_a_1562741_f0009_b.jpg)
Figure 10. Predicted (correlated) values versus simulated values for (a) the Nusselt number and (b) the Fanning friction factor
. Data are based on EquationEqs. (13)
(13)
(13) and Equation(19)
(19)
(19) . The predicted values are correlated via the number of wires
(see ) for specific Reynolds numbers
and geometry parameters
and
for an in-line arrangement.
![Figure 10. Predicted (correlated) values versus simulated values for (a) the Nusselt number Nust,y* and (b) the Fanning friction factor fst,y*. Data are based on EquationEqs. (13)(13) Nust,y*=Nust,∞+C1,NuC2,Nu(y*−1)1−y*−C2,Nu (13) and Equation(19)(19) fst,y*=fst,∞+C1,fC2,f(y*−1)1−y*−C2,f (19) . The predicted values are correlated via the number of wires nwires (see Table 1) for specific Reynolds numbers Rest and geometry parameters a and b for an in-line arrangement.](/cms/asset/81a7d72c-868a-4599-87c7-076332540d04/unht_a_1562741_f0010_c.jpg)
Table 3. Derived correlations for and
for an in-line wire structure.
Table 4. Derived correlations for coefficients of and
for in-line wire structure based on the EquationEqs. (13)
(13)
(13) and Equation(19)
(19)
(19) .
Figure 11. Auxiliary coefficients(a),
(b),
(c), and
(d) needed for calculation of correlated Nusselt number and friction factor based on for in-line arrangement. Geometry parameter
is shown on the contour lines.
![Figure 11. Auxiliary coefficients A˜Nu (a), B˜Nu (b), A˜f (c), and B˜f (d) needed for calculation of correlated Nusselt number and friction factor based on Table 3 for in-line arrangement. Geometry parameter a is shown on the contour lines.](/cms/asset/78146781-18f6-40e6-8c35-bbfa7562becb/unht_a_1562741_f0011_c.jpg)
Figure 12. Nondimensional entrance lengths and
for an in-line arrangement based on the Reynolds number
and geometry parameters
and
. Entrances lengths below 0.1 are not shown.
![Figure 12. Nondimensional entrance lengths Lth* and Lhy* for an in-line arrangement based on the Reynolds number Rest and geometry parameters a and b. Entrances lengths below 0.1 are not shown.](/cms/asset/840682ab-693b-4e84-840c-6468a4b847a5/unht_a_1562741_f0012_b.jpg)
Figure 13. Predicted (correlated) values versus simulated values for (a) the Nusselt number and (b) the Fanning friction factor
for a developed flow. Data are based on . The predicted values are correlated via the Reynolds number
and geometry parameters
and
for an in-line wire arrangement.
![Figure 13. Predicted (correlated) values versus simulated values for (a) the Nusselt number Nust,∞ and (b) the Fanning friction factor fst,∞ for a developed flow. Data are based on Table 3. The predicted values are correlated via the Reynolds number Rest and geometry parameters a and b for an in-line wire arrangement.](/cms/asset/9c6da055-5f27-4214-ba9d-84c68175df65/unht_a_1562741_f0013_c.jpg)
Figure 14. Predicted (correlated) values versus simulated values for (a) the Nusselt number and (b) the Fanning friction factor
. Data are based on EquationEqs. (13)
(13)
(13) and Equation(19)
(19)
(19) ( and ). The predicted values are correlated via the Reynolds number
, geometry parameters
and
, and the number of wires for an in-line wire arrangement.
![Figure 14. Predicted (correlated) values versus simulated values for (a) the Nusselt number Nust,y* and (b) the Fanning friction factor fst,y*. Data are based on EquationEqs. (13)(13) Nust,y*=Nust,∞+C1,NuC2,Nu(y*−1)1−y*−C2,Nu (13) and Equation(19)(19) fst,y*=fst,∞+C1,fC2,f(y*−1)1−y*−C2,f (19) (Tables 3 and 4). The predicted values are correlated via the Reynolds number Rest, geometry parameters a and b, and the number of wires for an in-line wire arrangement.](/cms/asset/8974c0e4-e3dc-4f4b-b36c-a40aabaef888/unht_a_1562741_f0014_c.jpg)
Table 5. Percentage of correlated data which satisfy a relative residual error below 5% and 10% for ,
,
, and
.
Table B1. Predicted correlation for coefficients of and
for staggered wire structure based on the EquationEqs. (13)
(13)
(13) and Equation(19)
(19)
(19) .
Table B2. Percentage of correlated data which satisfy a relative residual error below 5% and 10% for ,
,
, and
in staggered wire arrangement.