Influence factors of flow distribution and a feeder tube compensation method in multi-circuit evaporators

- Four influence factors of flow distribution in multi-circuit evaporators are investigated.
- A feeder tube compensation method for optimizing mass flow distribution is presented.
- Superheat uniformity was improved and up to 35% evaporator cooling capacity could be enhanced in uneven airflow condition.

This study investigates four influence factors of flow distribution in multi-circuit evaporators with distributor, including distributor inlet tube length, inclination angle, uneven airflow, and feeder tube length. Experimental tests and numerical simulations were carried out to evaluate the effect of these factors on superheat uniformity and refrigerant distribution performance. Additionally, a feeder tube compensation method for optimizing refrigerant distribution is presented that involves pressure drop fine-tuning of the feeder tube in each circuit coupled with a main expansion device to obtain more uniform superheat performance at all circuit outlets. To adopt this method, a model was developed to predict the best feeder tube length for each circuit. Experimental results show that when using feeder tubes with predicted lengths in condition of uneven airflow, the superheat uniformity was improved significantly, and up to 35% evaporator cooling capacity could be enhanced when airflow non-uniformity coefficient (Fair) was 0.6.