板式换热器(PHE)用于广泛的应用,因此,利用新的和独特的热源是至关重要的。R744的临界温度低,这使得其热物理性质的变化比其他超临界流体更平滑。因此,它可以用作PHE的可靠热流,特别是在高温下。通过与真实气体的NIST数据库集成的MATLAB构建了本地设计方法。最近生产的HFOs(R1234yf,R1234ze(E),R1234ze(Z),和R1233zd(E))用作流过三相的冷流体:液相,两相,和气相。进行了两步研究以检查以下参数:传热系数,压降,和有效性。第一步,用可变数量的板分析这些参数以确定下一步的合适数量。然后,用可变的冷通道质量通量研究了热流压力和冷流过热差的影响。第一步,结果表明,对于高于40的板数,所研究的参数差异不显著。同时,第二步表明,将热流压力从10兆帕增加到12兆帕,两相对流系数增加了17%,23%,75%,R1234yf为50%,R1234ze(E),R1234ze(Z),和R1233zd(E),分别。相比之下,将冷流过热温差从5K增加到20,使两相对流系数降低了14%,16%,53%,R1234yf为26%,R1234ze(E),R1234ze(Z),和R1233zd(E),分别。因此,R744适用于PHE作为驱动热源,特别是在较高的R744入口压力和低冷流过热差。
Plate heat exchangers (PHE) are used for a wide range of applications, thus utilizing new and unique heat sources is of crucial importance. R744 has a low critical temperature, which makes its thermophysical properties variation smoother than other supercritical fluids. As a result, it can be used as a reliable hot stream for PHE, particularly at high temperatures. The local design approach was constructed via MATLAB integrated with the NIST database for real gases. Recently produced HFOs (R1234yf, R1234ze(E), R1234ze(Z), and R1233zd(E)) were utilized as cold fluids flowing through three phases: Liquid-phase, two-phase, and gas-phase. A two-step study was performed to examine the following parameters: Heat transfer coefficients, pressure drop, and effectiveness. In the first step, these parameters were analyzed with a variable number of plates to determine a suitable number for the next step. Then, the effects of hot stream pressure and cold stream superheating difference were investigated with variable cold channel mass fluxes. For the first step, the results showed insignificant differences in the investigated parameters for the number of plates higher than 40. Meanwhile, the second step showed that increasing the hot stream pressure from 10 to 12 MPa enhanced the two-phase convection coefficients by 17%, 23%, 75%, and 50% for R1234yf, R1234ze(E), R1234ze(Z), and R1233zd(E), respectively. In contrast, increasing the cold stream superheating temperature difference from 5 K to 20 reduced the two-phase convection coefficients by 14%, 16%, 53%, and 26% for R1234yf, R1234ze(E), R1234ze(Z), and R1233zd(E), respectively. Therefore, the R744 is suitable for PHE as a driving heat source, particularly at higher R744 inlet pressure and low cold stream superheating difference.