Temperature control for a vehicle climate chamber using chilled water system

Dynamic Modeling and Full-Process Simulation of the Core Engine Test Rig Main Test System

“…By using Fluent 15.0 to conduct steady-state computation for the triple eccentric butterfly valve, Sun et al [18] discovered that the surface roughness may result in a big difference between the flow coefficient obtained by simulation without friction and the actual flow coefficient. The second type of research [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] focuses on the whole system rather than the valve, and thus generally uses the traditional 0D throttling flow-rate equation instead of the momentum equation to describe the dynamic throttling effect of the valve spool. In order to accurately describe the throttling effect, this simplified modeling method must take flow-rate equation, flow coefficient calculation, and valve-spool opening and closing rule into full consideration.…”

“…Firstly, as the core of the throttling model, the valve-spool or orifice throttling flow-rate equation is a semi-theoretical and semi-empirical formula. By the form of relationship between the flow rate and the upstream and downstream pressures, it can be roughly divided into the pressure ratio-based form [15,24,25] and the pressure difference-based form [15,[27][28][29][30][31][32][33][34][35][40][41][42]. The former generally applies to the condition of gas flow medium while the latter usually applies to the condition of liquid flow medium.…”

“…For example, in [15], the pressure ratio-based injector orifice model uses the first type of method, while the pressure difference-based orifice model uses the second type of method. Liang et al [42] investigated the temperature control of a vehicle climate chamber, and the flow coefficient of adjusting valves in the chilled water system also adopted the second type of method. As for the third type of method, Karimi et al [26] used a nozzle model with variable area for the modeling of the pressure reducer valve when simulating the liquid propellant engine pressurization systems, where the flow area is function of the opening and the flow coefficient is constant; the same treating method also occurred in the modeling of the first and second throttling orifices of a class of three-way pressure reducing valve by Gad [27].…”

“…The second type of simulation research covers both the information-known valves [15,25,[27][28][29][30][31][32][33][34][35][36] and the information-unknown valves [25,37,38,42], as well as the throttling devices, such as some orifices [39] or Venturi tube [40], and can be divided into the following three cases by the valve opening in the experimental process:…”

Entrainment performance enhancement of HVAC systems with active chilled beams

“…When 50mm < L N < 60mm, the ER can reach up to 3.35. Under other working conditions, ER also increases with nozzles to a maximum and then decreases.Table 5.17 shows corresponding L N under different working condition that gives maximum ER.The results inTable 5 16. show that despite of nozzles with various length, the primary volume flow rate fluctuates little.…”