After about 30 days with high-fouling potential water, the fouling resistance of BPHE A1 was about 9.
Suspended particles interfered with the water channel flow within the inlet and outlet regions of the plates, that is, between the BPHE water connecting ports and the central sections of the corrugated plates.
The refrigerant circulating in the BPHE A1 with a soft chevron angle of 30[degrees] was subjected to practically no subcooling at the outlet refrigerant port, suggesting that refrigerant exits the BPHE A1 in two-phase liquid and vapor mixture form if the heat flux is close to nominal design value.
The hydraulic performance of the BPHE is presented in the form of pressure drop penalty factors (PDPF) in Figure 5.
The pressure is taken at the inlet of the test BPHE while temperature sensors are installed before and after the test BPHE.
As summarized in Table 1, three BPHEs (A2, A3, and A4) had the same corrugation angle but different aspect ratios, while the fourth BPHE (A1) consisted of the same aspect ratio of A2 but with a different corrugation angle.
Then the water was circulated in the test BPHE and in the cooling tower installed in series in the experimental apparatus.
The LMTD accounts for neither the degree of superheat nor the degree of sub-cooling on the refrigerant side in the BPHE.
Due to the similarity in geometries and configurations on the cold and hot channels of a BPHE, the flow regimes and the Reynolds number exponents on both sides can be assumed identical in certain ranges of Reynolds numbers.
onepass] = single smallest cross sectional area of flow within channel in BPHE, [mm.
To be able to formulate two-phase flow in the BPHEs, comprehensive single-phase flow experimentation is first required to establish single-phase formulation.
While heat transfer coefficients and pressure drops have been studied extensively in the single-phase realm in PHEs, as documented by Ayub (2003), two-phase vaporization and condensation have not received as much attention, let alone in BPHEs.